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Samsung Electro-Mechanics — The Invisible Infrastructure of AI Silicon. MLCC (Power Stability), FC-BGA (Chip Substrate), and Camera Modules Dissected

Fri, 15 May 2026 00:00:00 +0000

Samsung Electro-Mechanics (SEMCO, KRX 009150) crossed KRW 3 trillion in quarterly revenue for the first time. 1Q26 revenue KRW 3.21T, operating profit KRW 280.6B. Package substrate revenue grew +45% year over year, becoming the lead actor of the rerating. The stock rose from KRW 830,000 in late April to KRW 1,024,000 in mid-May — a +23% move. Sell-side target prices jumped from KRW 1.0M to KRW 1.5M within weeks. Yet few investors can clearly state what SEMCO actually makes, why it is an “AI beneficiary,” and what each of its three divisions does. This article dissects SEMCO at the division level.

Key takeaways

SEMCO is not a chip maker. It makes the power-stability components (MLCC) and the substrates that connect AI chips to motherboards (FC-BGA) that AI silicon needs to function inside a server.
Three divisions: Component (MLCC, 46% of revenue, 67% of profit), Package Solution (FC-BGA, 20% of revenue, 15% of profit), Optics (camera modules, 34% of revenue, 18% of profit).
Core shift: previously a “smartphone parts maker.” Today, the rerating thesis is AI-server / xEV high-end MLCC + AI-accelerator FC-BGA in structural supply shortage.
1Q26 results: revenue KRW 3.21T (+17% YoY), operating profit KRW 280.6B (+40% YoY). Stripping a one-off severance charge of KRW 71.4B, underlying operating profit was KRW 352.0B.
The division that matters most: Component (MLCC) defends earnings. Package Solution (FC-BGA) drives the share price. Optics is the optionality bucket.
At KRW 1.02M today: expensive on 2026 numbers, defensible only if the AI-substrate cycle keeps running through 2027–2028. A patient approach — waiting for next prints — is more reasonable than chasing the move.

1. Start here — why is SEMCO an “AI beneficiary”?

1.1 The invisible infrastructure of AI silicon

In an earlier piece on Samsung Electronics, I called HBM “the workbench of AI silicon.” But even the best workbench (memory) and the best computer (GPU) won’t work if the power supply is unstable (the system crashes) or if the chip isn’t properly wired to the motherboard (data flow breaks).

What SEMCO makes is exactly this kind of “invisible infrastructure.”

What SEMCO parts do inside an AI server:

1. MLCC — the tiny power dam
 → Stores electricity for an instant and releases it smoothly
 → AI chips spike in power draw under compute load;
 MLCCs absorb those swings
 → A single AI server uses tens of thousands of MLCCs

2. FC-BGA — the chip's foothold
 → A high-density circuit substrate that connects AI chips
 (GPUs, CPUs) to the motherboard
 → Carries both power delivery and signal between chip and board
 → As AI chips get larger and more complex,
 substrates get bigger and stack more layers

3. Camera modules — the eyes
 → Cameras for phones, cars, robots
 → Not directly AI-driven, but a real option as the franchise
 expands into automotive and robotics

1.2 Why is supply tight right now?

In the Samsung Electronics piece, I noted that HBM is “absorbing fab capacity.” A similar phenomenon is unfolding in MLCC and FC-BGA.

MLCC:
→ AI servers draw a lot of power and swing hard
→ MLCC content per server has jumped
→ At the same time, xEV demand is also exploding
→ Supply can't be added quickly — high-voltage, high-temperature,
 high-reliability parts take long qualification cycles
→ Prices are starting to rise

FC-BGA:
→ Bigger AI chips need bigger substrates
→ Bigger substrates → more layers → lower yields
 (the percentage of substrates produced without defects falls)
→ Larger panels also fit fewer units per processing line
→ Greenfield substrate fabs take 2–3 years to build
→ Demand is rising now; meaningful new supply is a 2028+ event
→ From now through 2027 is the "supply-short" window

One-line summary: SEMCO isn’t an AI chipmaker; it makes the power and connectivity parts AI chips cannot run without — and those parts are in shortage today.

2. Dissecting the three divisions

2.1 SEMCO’s structure

Division	Key products	2025 revenue	Mix	2025 profit	Profit mix	Margin
Component	MLCC, inductors, chip resistors	KRW 5.20T	46%	KRW 609.4B	67%	11.7%
Package Solution	FC-BGA package substrates	KRW 2.30T	20%	KRW 135.2B	15%	5.9%
Optics	Camera modules	KRW 3.81T	34%	KRW 168.7B	18%	4.4%
Total		KRW 11.31T	100%	KRW 913.3B	100%	8.1%

Role-split inside SEMCO:
Component (MLCC) = defends profit (67% of operating profit)
Package Solution (FCBGA) = moves the share price (+45% YoY growth)
Optics (cameras) = builds top-line scale + future optionality

3. Component (MLCC) — the profit moat

3.1 What is an MLCC?

MLCC = Multi-Layer Ceramic Capacitor. The name is technical, but the job is simple — it stores electricity for an instant and supplies it smoothly to nearby chips.

Analogy: a water tank in a plumbing system

If tap water surges and dips, the flow is unstable.
A tank stores some water and releases it evenly.

MLCC does the same with electricity:
If current surges and dips, the chip misbehaves.
The MLCC briefly stores charge and releases it smoothly.

Size: smaller than a grain of rice (0.1mm–3mm)
Count: \~1,000 in a smartphone, tens of thousands in an AI server

3.2 Why does SEMCO MLCC matter?

MLCC market structure:
#1 Murata (Japan) \~33% share
#2 Samsung Electro-Mechanics \~23%
#3 Taiyo Yuden (Japan)
#4 Yageo (Taiwan)

→ The top four control most of the market
→ High entry barrier: hundreds of micrometer-thin ceramic layers
 stacked uniformly, fired at high temperature without defects
→ SEMCO holds up to 600-layer stacking technology

Why AI-server MLCC is especially hard:
→ Higher voltage, capacitance, and thermal tolerance than phone parts
→ Long qualification cycles; field failure can crash a whole server
→ The list of qualified suppliers is narrow
→ That narrowness translates into pricing power and margin

3.3 1Q26 print and outlook

1Q26 Component revenue was KRW 1.41T (+16% YoY), with utilization at 93% (vs. 70% Package and 66% Optics — the highest in the company).

Management said high-end MLCC demand for AI servers and data centers remains strong into 2Q. Both MLCC shipments and average selling price (ASP) are expected to rise quarter on quarter.

The most important change: selected MLCC products are starting to see price increases. Murata and Taiyo Yuden reported book-to-bill ratios of 1.36 and 1.31 — the highest in five years (post-2021). “BB > 1” simply means orders exceed shipments; the gap is now wide enough to talk about real undersupply.

4. Package Solution (FC-BGA) — the body of the rerating

4.1 What is FC-BGA?

FC-BGA = Flip Chip Ball Grid Array — a high-density circuit substrate that connects AI chips (GPUs, CPUs) to the motherboard.

Analogy: the chip's foothold

AI chips are small and dense, with tens of billions of transistors.
You can't solder them straight onto the server motherboard.
You need an intermediate "foothold" that delivers power and signal
between chip and board. That foothold is the FC-BGA substrate.

Why it's hard:
→ Bigger AI chips → bigger substrates
 (server substrates are >4× the area of consumer PC substrates,
 with 20+ layers)
→ Bigger substrates warp → chips lose contact
→ More layers must align precisely → yield drops sharply
→ Fine traces must be etched at 5–10 micrometers
 (about 1/10th the width of a human hair)

SEMCO became the first Korean company to mass-produce server FC-BGA,
in October 2022. In 2025, it publicly announced a data-center
substrate supply partnership with AMD.

4.2 Why this is “the body of the rerating”

The reason SEMCO went from KRW 830,000 to KRW 1,024,000 is Package Solution.

1Q26 Package Solution:
Revenue: KRW 725B (+45% YoY, +12% QoQ)
Growth drivers: high-end FC-BGA for AI accelerators, server CPUs,
 networking

Why the market got excited:
1. Customers want more than current capacity
 → demand > supply → pricing power sits with SEMCO

2. New big-tech customer awarded an AI-data-center networking
 substrate program
 → more customers = bigger future revenue

3. Long-term agreement (LTA) discussions are underway
 → not a one-quarter spike — structural demand → multiple expansion

4. Management signaled 2026 capex could double versus 2025
 → ramping investment = a confidence signal that demand is real

4.3 What only SEMCO can do

Typical substrate maker: makes FC-BGA only
SEMCO: makes FC-BGA AND MLCC

Why this matters:

AI servers reduce power loss by placing power-delivery components
directly under the chip. That means stacking — or embedding — MLCCs
on or inside the substrate.

Because SEMCO makes both, it can develop "MLCC-in-substrate"
integration internally.

Murata (MLCC-only) and Ibiden (substrate-only) can't replicate this
in-house.

→ This dual capability is potentially SEMCO's most durable long-run moat.

4.4 What is not yet proven

Package Solution’s 2025 operating margin was just 5.9%. Revenue grew +13% YoY, but profit fell -14%. Why? Raw-material costs (CCL, prepreg) rose +19% while average selling prices rose only +4%.

The key question: in 2026, will revenue growth come with margin recovery? If only the top line grows and margins stagnate, the current price is hard to justify. Whether 2Q Package Solution margin lifts above 12% is the single biggest gate for the rerating to continue.

5. Optics (camera modules) — big revenue, not the protagonist

Optics is SEMCO’s smartphone- and automotive-camera-module business. 2025 revenue KRW 3.81T (34% of company), margin 4.4%.

State of play:
→ Revenue is large (a third of the company)
→ Margin is the lowest in the portfolio (4.4%)
→ Sensitive to the smartphone flagship cycle
→ Not the protagonist of the rerating

Future optionality:
→ ADAS cameras for EVs (number per vehicle is rising)
→ In-cabin driver-monitoring cameras
→ Vision cameras for robots and humanoids
→ Management flagged a robotaxi product ramp starting in 2Q

Current market share: \~9% (down from \~11% in 2024)
→ Real technology, but not the rerating thesis

Investor view: Optics adds revenue stability but does not move the stock. MLCC and FC-BGA do. Automotive and robotics cameras are long-dated options — not something to pay for at today’s multiple.

6. Valuation — already expensive, but for a reason

6.1 Where the stock sits

As of May 15, KRW 1,024,000 / share, market cap ~KRW 76.5T. Up +23% from late April.

Reference	PER	Reading
Trailing 12 months	~110x	Optically very expensive
2026E earnings	~58x	Once profit recovery is reflected, lower
2027E earnings	~38x	Only makes sense if the AI-substrate cycle runs into 2027

6.2 Sell-side target prices have run

Feb : Samsung Sec KRW 450,000 (on 2027 BPS)
Mar : Hana Sec KRW 550,000 (2026 EPS × 37.5x)
Early-Apr: SK Sec KRW 600,000 (global peer PER 40x)
Mid-Apr: Hana Sec KRW 810,000 (2027 EPS × 35x)
Early-May: Hana Sec KRW 1,000,000 (2027 EPS × 40x)
Mid-May: KB Sec KRW 1,400,000
 NH IB / SK Sec KRW 1,500,000

→ Target prices more than tripled in roughly three months.

Why so fast? The valuation frame itself shifted. SEMCO used to trade as a “Korean electronic-parts maker.” Today, the sell side benchmarks it against global AI-substrate and passive-component peers — Japan’s Ibiden, Taiwan’s Unimicron, Japan’s Murata. Apply those multiples and targets jump.

6.3 Scenario-based fair value

Scenario	2027E EPS	Applied PER	Fair value	vs. spot
Bear (MLCC price hike contained, FC-BGA capex weighs)	KRW 22,000	33x	KRW 730,000	-29%
Base (AI cycle persists + Package margin recovers)	KRW 26,800	43x	KRW 1,150,000	+12%
Bull (MLCC + FC-BGA price hikes together + LTA)	KRW 30,000	50x	KRW 1,500,000	+47%

Today’s KRW 1.02M offers +12% upside in the base case — and -29% downside if the bear case prints, +47% upside if the bull case prints. At this price, waiting for the next earnings confirmation is more reasonable than chasing the rally.

6.4 The key framing: not “cheap,” but “expensive without continuous earnings upgrades”

Where SEMCO sits today:
"Is it a good company?" → Yes
"Is the stock cheap?" → No
"So I shouldn't buy?" → Not necessarily — conditionally yes

Conditions:
→ 2Q operating profit above KRW 400B (vs. consensus KRW 378.8B)
→ MLCC price hike spreading from distributors to direct customers
→ Package Solution margin moving above 12%
→ LTA or customer pre-investment formalizing

Two of these = the buy thesis works at today's price.
Zero of these = waiting for a pullback is the right call.

7. What to watch from here

7.1 Earnings triggers

Trigger	Bull line	Bear line	When
2Q operating profit	above KRW 400B	below KRW 360B	Late July
MLCC price hike	Spreads to direct AI customers	Stays at cost pass-through	2Q
FC-BGA utilization	Full utilization in 2H	New-customer ramp delays	3Q
Package Solution margin	12%+ in 2Q	Below 10%	Late July
MLCC channel inventory	~4 weeks (tight)	6+ weeks (loosening)	Quarterly

7.2 Multiple triggers

Trigger	Why it matters
Sustained AI infrastructure capex	The end demand for both FC-BGA and MLCC
Customer long-term agreements (LTAs)	Proves “not one-off” — structural demand
Murata / Taiyo Yuden BB ratio	Leading indicator of MLCC cycle (5-year high today)
Global substrate capacity plans	How long the supply shortage lasts
Glass Core substrate JV	A next-generation packaging option (2027+)

7.3 Risks to keep in view

Risk	Description
Already expensive	2027 PER ~38x. If earnings estimates roll over, the stock falls hard
FC-BGA capex burden	Doubling capex doubles depreciation; revenue must follow or margin compresses
Pass-through failure	If CCL, gold, copper inflation can’t be passed on, margins suffer
Smartphone weakness	Camera modules and some MLCC SKUs remain phone-cycle exposed
AI capex peak	If AI server investment slows, FC-BGA + MLCC demand bases weaken

8. How this links to other posts

Samsung Electronics piece: "HBM is the workbench of the AI server"
→ SEMCO: "MLCC is the power stabilizer, FC-BGA is the chip's foothold"

Jeju Semiconductor piece: "Commodity DRAM is short because of AI"
→ SEMCO: "Power components and chip substrates are short because of AI"

Robotics value-chain piece: "Part 1 flagged SEMCO ramping a
humanoid camera in 2H"
→ SEMCO: that ramp lives inside the Optics optionality bucket

All three sit on the same logic:
AI capex → shortage of components, materials, substrates →
pricing power for the bottleneck supplier.

9. The one-line bottom line

SEMCO is the invisible infrastructure layer of AI silicon. MLCC stabilizes power; FC-BGA connects the chip to the board. Both are short of supply. MLCC prices have started to rise; FC-BGA demand has overtaken capacity. If this structure runs through 2027, SEMCO gets rerated from “smartphone parts maker” to “AI infrastructure parts platform.”

But at KRW 1.02M, much of that thesis is already in the price. On 2027 earnings, PER is ~38x — “great company” and “great entry price” are different questions. To chase the move from here, the numbers have to confirm: 2Q operating profit above KRW 400B, MLCC price hikes spreading, FC-BGA margins recovering.

One-line: this is not a cheap stock — it is a stock that is only “not expensive” if earnings upgrades keep coming. The pace of revision matters more than the headline news flow.

This article is research and commentary only and is not investment advice. Divisional revenue and profit figures are based on Samsung Electro-Mechanics’ 2025 annual report and 1Q26 earnings release. The 1Q26 operating profit of KRW 280.6B includes a one-off severance charge of KRW 71.4B. Utilization figures (Component 93%, Package 70%, Optics 66%) are 2025 full-year averages. The ~23% MLCC market share figure is the company’s own estimate. The AMD substrate partnership is per SEMCO’s official disclosure. The new big-tech customer name is not publicly disclosed. The valuation scenarios (Base KRW 1.15M, Bull KRW 1.50M, Bear KRW 730K) are the author’s estimates and may be wrong. Sell-side targets (NH / SK KRW 1.5M, KB KRW 1.4M, Hana KRW 1.0M, etc.) reflect each broker’s report and are subject to change. Glass-core JV mass production is a 2027+ plan and not confirmed. MLCC price hikes are at an early stage in select distributor channels; broader pass-through is not yet confirmed. The analysis may be wrong. Data cut-off: May 15, 2026 KST.

Disclaimer: For research and information purposes only. Not investment advice. Names cited are for analytical illustration; readers should perform their own due diligence and consult licensed advisors before any investment decision.

Two Betas of AI Back-End — Substrates Are a 'Volume Beta,' Test Sockets Are a 'Consumables Beta.' Same AI Tailwind, Completely Different Structures

Fri, 15 May 2026 00:00:00 +0000

📚 AI back-end series Previously: Samsung Electro-Mechanics MLCC and FC-BGA deep dive, Jeju Semiconductor legacy-memory thesis Read next: AI back-end — 11 stocks side by side on 2027E PER × OP growth

Who actually makes money when AI silicon sells? Nvidia (GPU) and SK hynix (HBM) are the names that come to mind first. But the “back end” of the supply chain has major winners too. We call it AI back-end. Two regions matter most: substrates and test sockets. Both are parts that an AI chip passes through before completion — but the investment structures are completely different. Substrates are a bet on “AI server units.” Test sockets are a bet on “AI chip complexity.” Margins are roughly 3x higher in test sockets, and momentum is faster in substrates. Which is the better investment depends on how long you plan to hold.

Key takeaways

Two regions in AI back-end: substrates and test sockets.
Substrate essence: a “direct CAPEX beta” on AI-server build-out. More units → more revenue; larger packages → higher ASP.
Test-socket essence: a “high-margin consumables beta” on chip complexity. More complex chips → harder testing → more / harder sockets.
Profitability gap: on 1Q26, Daeduck Electronics 14.8% vs ISC 35% vs LEENO Industrial 47.4%. Test sockets dominate.
Momentum gap: substrate earnings revisions are faster — ASP hikes, new big-tech LTAs, capacity tightness are all near-term catalysts.
Cycle risk: substrates are a CAPEX cycle (shortage → CAPEX → glut). Test sockets, being consumables, run with lower cyclicality.
Bottom line: short-term momentum trades → substrates (Daeduck Electronics, Samsung Electro-Mechanics). 1–2 year compounding → test sockets (LEENO Industrial, ISC). These are not the same “AI theme.”

1. Setup — what substrates and test sockets actually are

1.1 How AI silicon gets made

Production flow of AI silicon:

1. Design (Nvidia, AMD, Google, Meta, etc.)
2. Wafer fab (TSMC, Samsung Foundry)
3. Dicing
4. Packaging (HBM, interposer, package substrate join)
 ← "substrates" used here
5. Test (performance / reliability / burn-in)
 ← "test sockets" used here
6. Shipment

Substrate = "the pedestal the chip sits on"
Test socket = "the slot a chip plugs into briefly for testing"

Both are parts AI silicon passes through before completion,
but their roles and usage patterns are completely different.

1.2 Substrate — what is it

A substrate connects the microscopic circuitry inside a chip
(nanometer scale) to the outside world (millimeter scale).

What it does:
1. Electrical connection (thousands of pins → board)
2. Mechanical support (stable mounting of large packages)
3. Thermal management (heat-flow path away from the chip)
4. Signal integrity (high-speed signals without loss)

Why AI matters:
- AI chips are much larger than typical silicon
 (Nvidia H100 = 814 mm², 2–3x a typical CPU)
- Thousands to tens of thousands of pins
- High-speed data movement
- Heavy heat budget (700W+)

→ Specialized substrates (FC-BGA) are required
→ Harder to make and more expensive than ordinary substrates
→ Korean players: Samsung Electro-Mechanics, Daeduck Electronics,
 Isu Petasys.

1.3 Test socket — what is it

A test socket is a slot used briefly to test a finished chip.

What it does:
1. Electrically connects every chip pin to the tester
2. Verifies the chip works under signal / power / temperature stress
3. Filters out failing units
4. Reliability validation (long-duration testing)

Analogy:
Chip = car
Test socket = the diagnostic port at the inspection bay
→ Connected briefly during inspection, then disconnected
→ The same port is used for many different cars
→ Ports wear out over time and have to be replaced

Why AI matters:
- AI chips are expensive (\~USD 30k for an H100)
- A single bad unit costs a lot → test intensity rises
- High-current / high-speed / high-temperature environments
 → tougher socket spec
- Each chip generation needs new sockets → recurring revenue

Korean players: LEENO Industrial, ISC, TSE.

1.4 Why they are not the same “AI theme”

Substrate:
- Made once, shipped with the chip (capital-good character)
- Roughly one substrate per AI server
- Revenue = volume × ASP
- Adding capacity = CAPEX burden

Test socket:
- Reused many times, then replaced (consumable character)
- Roughly 50–200 sockets to test 10,000 chips
- Revenue = chip output × test intensity × socket replacement
- Capacity additions are smaller

Margin structure:
Substrate: OPM \~10–15% (CAPEX, depreciation drag)
Test socket: OPM \~30–50% (custom design, consumable economics)

→ Both benefit from AI,
→ but revenue mix, margin profile, and cycle sensitivity differ.

2. The substrate side — “AI server volume beta”

2.1 What 1Q26 showed

Samsung Electro-Mechanics (009150) — Package Solution segment
(FC-BGA-led):
1Q26 revenue: KRW 725B
YoY: +45%
QoQ: +12%

Daeduck Electronics (353200):
1Q26 revenue: KRW 346.3B (YoY +61%)
1Q26 OP: KRW 51.3B (turn-around to black)
OPM: 14.8%

Product mix:
- FCCSP (mobile-grade package substrate): 39%
- FCBGA (PC / server-grade): 23%
- CSP (memory): 22%
- MLB (multilayer board, AI server): 16%

YoY growth:
- Package substrates: +65%
- MLB: +43%

→ AI-server package substrates + network boards growing together
→ A direct beta on AI infrastructure.

2.2 Why substrates are short

Characteristics of AI-server FC-BGA:
- Surface area 2–3x a PC FC-BGA
- Multilayer (20–30 layers)
- High-speed signaling (PCIe 5.0 / 6.0)
- Strict thermal management

Companies that can make these:
- Korea: Samsung Electro-Mechanics, Daeduck, LG Innotek, Isu Petasys
- Taiwan: Unimicron, Nan Ya PCB
- Japan: Ibiden, Shinko Denki

The problem: capacity (CAPA) can't keep up with demand
- Big-tech AI-server orders have exploded
- Greenfield substrate fabs take 2–3 years to build
- Short supply → ASP hikes

Press cited:
"Samsung Electro-Mechanics FC-BGA demand exceeds capacity by \~50%;
 price-hike negotiations under way."

→ This is why substrate stocks have been strong.

2.3 Substrate cycle risk

Substrate is a classic CAPEX-cycle industry:

Up-cycle (today):
shortage → ASP hike → margin expansion → stock strength
→ companies announce sizable CAPEX

Build phase (2026–2027):
fabs under construction → revenue rising, CAPEX burden rising
→ stocks still trending strong

Build complete (2027–2028):
new fabs come online → supply surges
→ if demand doesn't keep up, prices fall
→ margins squeeze → stocks weaken

Historical patterns:
2017–2018 memory cycle: same shape
2021–2022 MLCC cycle: same shape

→ For substrate investing, "where in the CAPEX cycle" is the key
→ Today: early- to mid-stage of an up-cycle
→ Until build-out completes, upside is intact.

3. The test-socket side — “chip-complexity beta”

3.1 What 1Q26 showed

ISC (095340):
1Q26 revenue: KRW 68.3B
1Q26 OP: KRW 23.6B
OPM: 35%
Math: 23.6 / 68.3 = 34.55%

Revenue mix:
- AI revenue: KRW 55.3B (81% of total)
- Data-center revenue: KRW 54.2B (79% of total)
→ Already an "AI data-center company."

LEENO Industrial (058470):
1Q26 revenue: KRW 99.77B
1Q26 OP: KRW 47.30B
OPM: 47.4%
Math: 47.30 / 99.77 = 47.41%

Revenue mix:
- IC test sockets: 64.10%
- LEENO pins (pogo): 24.65%
- Medical components: 10.46%

→ Custom-designed sockets + vertically integrated pin manufacturing
→ 47% OPM is at the top of Korean manufacturing.

3.2 Why margins are this high

Structural features of the test-socket industry:

1. Customer-specific designs
 → pin layout, size, signal conditions vary by chip
 → hard to standardize → pricing power

2. High qualification cost
 → each new chip requires socket design / test / qualification
 → once qualified, locked in until end-of-life of that chip
 → reliability competition, not price competition

3. Consumable nature
 → sockets wear out / degrade and need periodic replacement
 → recurring revenue

4. Refresh with every chip generation
 → new chip = new socket
 → faster chip cadence = faster revenue cadence

5. Small TAM (a few tens of USD billion)
 → too small for mega-cap entrants
 → oligopoly of specialist players

All five conditions together enable 30–50% OPM.

3.3 Why AI made test sockets more important

AI chip characteristics:

1. Expensive (USD 10k–30k per unit)
 → cost of a single bad unit is high
 → test intensity ↑

2. High pin count (thousands–tens of thousands)
 → more complex sockets
 → ASP ↑

3. High current / temperature / speed
 → tougher socket durability requirements
 → shorter replacement cycle

4. SLT (System-Level Test) share rising
 → from simple functional test → full system test
 → longer test times
 → more socket usage

5. New modules: HBM, SOCAMM2, etc.
 → new socket categories
 → fresh revenue lines

→ In the AI era, test-socket demand grows
 faster than chip output.

3.4 ISC vs LEENO Industrial

Both are "test-socket companies," but their structures differ.

ISC (rubber-socket strength):
- Core tech: silicone rubber sockets
- Strength: AI data-center mass-production testing, SLT
- Customers: global GPU / ASIC majors
- Exposure: AI data center 81%
- Profile: direct AI beta (volatility higher)
- 1Q26 OPM: 35%

LEENO Industrial (pogo-pin strength):
- Core tech: pogo pins, in-house pin manufacturing
- Strength: R&D, mobile AP, RF, ASIC development
- Customers: diversified (hundreds of accounts)
- Exposure: many chip categories (lower AI share than ISC)
- Profile: quality compounder (more stable)
- 1Q26 OPM: 47.4%

→ Don't lump them as "the same test-socket stock."
→ ISC = AI data-center beta
→ LEENO = diversified high-margin platform

They are complements, not substitutes.

4. Head-to-head

4.1 1Q26 operating margins

Same "AI back-end beneficiaries," different margin profiles:

Daeduck Electronics (substrate): 14.8% ████
Samsung E-M Package Solutions: \~12% ███
ISC (test socket): 35.0% █████████
LEENO Industrial (socket): 47.4% ████████████

KRW 100 of revenue → OP:
Daeduck: KRW 14.8
ISC: KRW 35.0
LEENO: KRW 47.4

→ Roughly 3x spread on the same revenue
→ The result of structural industry differences.

4.2 Growth pace vs margin stability

Metric	Substrate (Daeduck)	Test socket (ISC)	Test socket (LEENO)
1Q26 revenue YoY	+61%	Strong YoY	+18%
1Q26 OP YoY	turnaround	Strong YoY	+35%
OPM	14.8%	35.0%	47.4%
AI exposure	Mid–high	Very high (81%)	Mid
Volatility	High	Mid	Low
Cycle sensitivity	High	Mid	Low

Summary:
- Revenue growth: substrate (Daeduck) > test socket
- Margin level: test socket > substrate
- Margin stability: LEENO > ISC > substrate
- Direct AI beta: ISC > Daeduck > LEENO.

4.3 Cycle risk

Substrate cycle risk (high):
- Shortage → CAPEX → glut, in repeat
- 2–3 year build lead time
- When the cycle rolls, utilization and ASP fall together
- Depreciation pressures margin

Test-socket cycle risk (low):
- Consumable economics dampens revenue volatility
- Customer-specific design keeps pricing stable
- New chips keep being released
- Quarterly volatility still exists

Long-hold perspective:
→ Test sockets are far more stable
→ avoids the substrate CAPEX cycle

Short-momentum perspective:
→ Substrate momentum is stronger
→ ASP-hike / capacity-tight headlines are more frequent.

5. Investment priority — different answers for different horizons

5.1 Short-term momentum (3–6 months) — substrates win

Why:
- Earnings-revision pace is faster
- Steady stream of ASP-hike headlines
- Probability of new big-tech LTA
- AI-server shipments accelerating

Order of preference:
1. Daeduck Electronics: turnaround + AI MLB / FC-BGA beta
2. Samsung Electro-Mechanics: AI FC-BGA + MLCC combo
3. Isu Petasys (complement): ultra-high-layer MLB strength

Caveats:
- Substrates have already moved a lot
- Check the CAPEX-cycle position
- Wait for the macro gate to clear (see earlier post).

5.2 Hold 1–2 years (quality growth) — test sockets win

Why:
- Margin structure is structurally superior
- Smaller cycle risk
- AI chip diversification = more socket categories = revenue diversification
- Active capacity expansion (new fabs)

Order of preference:
1. LEENO Industrial: highest quality, but the multiple is rich
2. ISC: direct AI data-center beta
3. TSE (complement): growth at a more reasonable price

Caveats:
- LEENO faces margin-impact risk during the new-fab move
- ISC has quarterly volatility (1Q26 QoQ -6%)
- Both trade at 30–45x PER.

5.3 A combined AI back-end portfolio

Aggressive (momentum tilt):
- Daeduck Electronics 40%
- ISC 30%
- Samsung Electro-Mechanics 20%
- LEENO Industrial 10%

Balanced (growth + stability):
- LEENO Industrial 30%
- Samsung Electro-Mechanics 25%
- ISC 25%
- Daeduck Electronics 20%

Defensive (quality tilt):
- LEENO Industrial 40%
- Samsung Electro-Mechanics 30%
- ISC 20%
- Daeduck Electronics 10%

→ If you must pick one, by horizon and volatility tolerance:
→ 1y+ hold: LEENO Industrial
→ 3–6 months: Daeduck Electronics
→ Direct AI data-center beta: ISC.

6. Four common misconceptions

6.1 #1: “Both are AI plays, so they’re the same”

As shown:
- OPM differs by 3x
- Cycle sensitivity differs
- Revenue mix differs

Grouping them as one bucket weakens diversification.
→ Volatility moves together
→ Pairing with another sector is more effective.

6.2 #2: “Pogo sockets are being replaced by rubber sockets”

Only partially true:

Where the shift happens:
- AI GPU / ASIC large-die chips
- High-current / high-speed signal testing
- SLT (System-Level Test)
→ Rubber-socket penetration rises (ISC strength)

Where it doesn't:
- High-precision R&D testing
- Mobile APs, RF chips
- Small-batch / many-SKU production
→ Pogo retains share (LEENO strength)

→ Not "the whole market converts" — it is "market segmentation"
→ Therefore ISC and LEENO are complements
→ It is rare for only one of them to do well.

6.3 #3: “Substrate stocks have run too much”

The right question is not the absolute level,
it is "where in the CAPEX cycle are we."

Now:
- Shortage still in progress
- ASP-hike negotiations under way
- LTAs with big-tech under discussion
- CAPEX announcements have started, but ramps are 2–3 years away

→ Early- to mid-stage of an up-cycle
→ Price moved, but the cycle has not topped.

That said, from these levels:
- Scaled entries recommended
- Wait for the macro gate to clear
- Chasing is inefficient.

6.4 #4: “The test-socket TAM is too small”

True on the headline number, but the read is wrong:

Test-socket TAM:
- \~USD 3–4 billion
- Less than 2% of the memory market (\~USD 200B)
- Small in absolute terms

Why that's actually a feature:
- Too small for mega-cap entrants
- Sustains the specialist oligopoly
- Price competition stays mild
- 30–50% OPM achievable

Compare:
A USD 200B business at 5% OPM vs
a USD 4B business at 45% OPM
→ Comparable absolute OPDollars
→ The second is more stable and more predictable.

This is the structure LEENO and ISC benefit from.

7. The next six months — checklist

7.1 Substrates (cycle-intact confirmation)

Positive signals:
□ FC-BGA ASP hikes continue
□ Samsung E-M / Daeduck add new big-tech customers
□ Large-die / high-layer mix lifts in revenue
□ MLB demand persists at 800G / 1.6T networking
□ Utilization stays above 90% even with CAPEX rising

Negative signals:
□ ASP hike negotiations delayed / fail
□ Big-tech AI server orders decelerate
□ Pace of new CAPEX announcements accelerates (glut concern)
□ Utilization drops below 80%

Frequency: quarterly earnings + mid-quarter IR commentary.

7.2 Test sockets (growth-intact confirmation)

ISC:
□ 3Q26 revenue re-acceleration (2Q may be a ramp-prep quarter)
□ New data-center infrastructure customer first-volume ramp
□ SOCAMM2 mass-production testing revenue begins
□ SLT mix stays above 70%
□ AI revenue mix stays above 80%

LEENO Industrial:
□ Progress on the new-fab move
□ No margin damage during the move (OPM 45%+ holds)
□ Customer diversification (Apple / TI / HPC / ASIC expansions)
□ Strong R&D socket demand
□ No overhang / governance issues

Frequency: quarterly earnings.

7.3 The macro backdrop

The macro gate from the earlier post:
- US 10-year below 4.45%
- Brent below 105
- USD/KRW below 1,480
- VIX below 18

These must clear for:
- Broad risk-asset recovery
- Back-end stocks to ride the trend
- Good earnings to translate into good price.

If the gate doesn't clear:
- Multiples stay pressured independent of fundamentals
- Wait for confirming close / turnover before scaling in.

8. How this connects to other posts

Samsung Electro-Mechanics piece:
→ MLCC + FC-BGA 1Q26 dual beneficiary
→ The most detailed stock covered in this article's substrate side
→ Scenario PERs for how far the multiple can stretch

Jeju Semiconductor piece:
→ "Commodity memory in shortage because of AI"
→ Another AI back-end shape (memory shortage beta)

Samsung Electronics strike piece:
→ Key variable for the memory supercycle
→ AI silicon → AI server → memory / substrate / test socket
→ Disruption in one ripples into the back end

KOSPI crash + macro-gate piece:
→ "Cycle before the stock"
→ Names in this post also rational only after the macro gate clears.

9. The one-line bottom line

When AI silicon sells, the first beneficiaries are the GPU and HBM makers. But the back end also has two big winners — substrates and test sockets.

Both are grouped as “AI back-end,” but the structures are completely different. Substrates are an “AI server volume beta.” Volumes rise, packages get bigger, ASPs lift — direct upside. Momentum is fast and operating margins expand from a ~12–15% base in 1Q26. But this is a CAPEX-cycle industry, and the build-out-complete date is the risk.

Test sockets are a “chip-complexity beta.” As chips get more complex, testing gets harder, and new sockets are needed each time. OPM sits at 35% for ISC and 47% for LEENO — roughly 3x substrate margins. Consumable economics dampen cyclicality. The downsides: the TAM is small and multiples are already rich.

Don’t lump them as one “AI theme.” For short-term momentum, substrates (Daeduck Electronics, Samsung Electro-Mechanics) lead. For 1–2 year holding, test sockets (LEENO Industrial, ISC) make more sense. The best play is to hold both as complements — when substrates shake at a cycle peak, test sockets defend; when test sockets feel multiple pressure, substrates’ momentum carries.

Same AI tailwind, completely different structures — understanding just that lifts the quality of back-end investment decisions by a full step.

This article is research and commentary only and is not investment advice. Samsung Electro-Mechanics 1Q26 figures are per the company’s official IR release. Daeduck Electronics 1Q26 (revenue KRW 346.3B, OP KRW 51.3B, OPM 14.8%) are per its IR materials. ISC 1Q26 (revenue KRW 68.3B, OP KRW 23.6B, OPM 35%, AI revenue mix 81%, data-center mix 79%) are per its IR materials. LEENO Industrial 1Q26 (revenue KRW 99.77B, OP KRW 47.30B, OPM 47.4%) is per preliminary disclosure reporting; product-mix figures (IC test sockets 64.10%, LEENO pins 24.65%, medical components 10.46%) are per the quarterly report. OPM uses operating profit divided by revenue, rounded to one decimal place. AI / data-center revenue shares are derived from company disclosures. The operating-margin comparison reflects a single quarter (1Q26); annual averages may differ. CAPEX-cycle risk, new-fab transition margin risk, and AI demand volatility are author judgments and not certainties. Global macro variables (US rates, oil, FX, VIX) can independently move the stocks. The analysis may be wrong. Data cut-off: May 15, 2026 KST.