Wafer Deposition: CVD, PVD, ALD & Electroplating

Deposition adds thin films of material to the wafer surface. It is the primary layer-build operation in front-end fabrication: every patterned layer of the chip begins with a deposition step. Gate dielectrics, spacers, diffusion barriers, interconnect metals, capacitor plates, and hundreds of other structural elements are all formed by depositing a specific material in a specific thickness and then selectively removing parts of it through lithography and etching. A 3nm logic wafer passes through deposition tools 100 or more times across its fab cycle, each time adding a new layer to the growing device stack.

Deposition is the largest single category of wafer fab equipment spending, rivaled only by lithography. The tool market concentrates at four vendors: Applied Materials and Lam Research dominate CVD and PVD; ASM International leads in atomic layer deposition (ALD); Tokyo Electron holds strong positions in PECVD and batch ALD. Below that tier, Aixtron serves compound semiconductor and LED MOCVD; Veeco serves specialty epitaxy and atomic layer etch-deposition integration. Precursor chemistry supply is a separate concentration layer covered under Process Consumables — specialty molecules like TMA, HfCl₄, and WF₆ come from a small supplier base of high-purity precursor specialists.

Deposition Methods

Deposition divides into five primary methods, each optimized for specific material classes, thickness ranges, and step-coverage requirements. Most advanced-node fabs run all five. The method chosen at each layer is dictated by film properties needed, structural geometry (conformality requirements), and thermal budget constraints.

Method	Process	Primary Use
CVD (Chemical Vapor Deposition)	Gas-phase precursors react on the wafer surface to form the film; variants include LPCVD, PECVD, HDP-CVD, SACVD	Oxides, nitrides, polysilicon, tungsten fill, dielectric stacks
PVD (Physical Vapor Deposition)	Sputtering or evaporation from a solid target deposits material directly on the wafer	Metal barriers (Ti, Ta, TiN, TaN), seed layers for electroplating, aluminum interconnect in legacy processes
ALD (Atomic Layer Deposition)	Self-limiting alternating precursor pulses build film one atomic layer at a time	High-k gate dielectric (HfO₂), ultra-thin barriers, high-aspect-ratio fills, GAA nanosheet surrounds
Epitaxy	Single-crystal film grown on a crystalline substrate; silicon, SiGe, Ge, or compound semiconductors	Transistor source/drain (SiGe for PMOS, SiC for NMOS), GaN HEMT stacks, SiC power device drift layer
Electroplating (ECD)	Metal ions deposited from liquid solution onto a conductive seed layer	Copper damascene interconnect fill; cobalt fill for advanced-node contacts
Spin-on	Liquid precursor spun onto wafer and cured; simpler than vapor-phase methods	Some low-k dielectrics, spin-on glass, dopant sources, planarization materials

Film Materials

Deposition produces a wide range of films, each engineered for a specific electrical or structural role in the device. The material set has expanded substantially as scaling has pushed the industry away from simple silicon-oxide-aluminum stacks.

Material Class	Examples	Role
Dielectrics	SiO₂, Si₃N₄, SiON, low-k (SiOCH, porous SiOC)	Insulation, spacers, inter-metal dielectric, passivation
High-k dielectrics	HfO₂, HfSiO, ZrO₂, Al₂O₃	Gate dielectric in HKMG and GAA logic; DRAM capacitor dielectric
Interconnect metals	Cu (electroplated), Co (advanced nodes), W (contacts and vias)	Signal and power routing across metal levels
Barriers / liners	TiN, TaN, Ru, WN	Prevent metal diffusion into dielectrics; adhesion and wetting layers
Gate metals	TiN, TiAl, TaN, W	Work-function metals in HKMG gate stacks
Semiconducting epi	Si, SiGe, Ge, SiC, GaN, III-V	Channel and source/drain in advanced transistors; drift layers in power devices
Polysilicon	Doped and undoped poly-Si	Legacy gate electrode; dummy gates in RMG flow; 3D NAND word lines
Magnetic films (emerging)	CoFeB, MgO	MRAM stacks; embedded non-volatile memory

Equipment Vendors

Deposition equipment is dominated by four vendors, each with primary strength in one or more methods. Specialty suppliers serve niche applications (compound semiconductor MOCVD, specialty epitaxy, ultra-advanced atomic-scale tools).

Vendor	HQ	Primary Strengths
Applied Materials	United States	CVD, PVD, ALD, electroplating (Endura, Producer, Olympia platforms); broadest product line in deposition
Lam Research	United States	CVD, ALD, electroplating; strong in 3D NAND high-aspect-ratio deposition and advanced integrated etch-deposition flows
ASM International	Netherlands	ALD market leader; batch ALD and epitaxy platforms; dominant in HKMG gate dielectric and advanced GAA
Tokyo Electron (TEL)	Japan	PECVD, batch ALD, thermal CVD; integrated cluster platforms
Kokusai Electric	Japan	Batch LPCVD and batch ALD furnaces for mature and memory fabs
Aixtron	Germany	MOCVD for compound semiconductors (GaN, SiC, III-V) and micro-LED
Veeco Instruments	United States	Specialty MOCVD, ion beam deposition, advanced packaging deposition tools
NAURA	China	Chinese domestic CVD and PVD tools for mature-node capacity

Precursor Chemistry Supply

Every deposition step consumes a specialty precursor chemistry — the molecule that reacts on the wafer surface to form the film. Precursor supply is a distinct concentration layer below the equipment tier. Inorganic gas precursors (silane SiH₄, dichlorosilane SiH₂Cl₂, tungsten hexafluoride WF₆, ammonia NH₃) come from specialty gas suppliers including Resonac (formerly Showa Denko), Kanto Denka Kogyo, Central Glass, Linde, and Air Liquide. Metal-organic and specialty molecular precursors (TMA for aluminum oxide, HfCl₄ and tetrakis precursors for hafnium oxide, cobalt and ruthenium precursors, novel ALD precursors) come from a narrower supplier set: Entegris, Merck/EMD Electronics (via the absorbed Versum specialty gases line), UP Chemical, Adeka, and DNF.

Precursor qualification at a fab is chemistry-specific, tool-specific, and often process-specific. A new precursor can take six to twelve months to qualify at an advanced node. This creates structural supplier lock-in: once qualified, a precursor supplier is difficult to displace, which supports margin at the top suppliers but concentrates risk if a single supplier site has a disruption. The 2020 Entegris precursor supplier fire, for example, caused industry-wide reallocation of ALD precursor supply for several months. See Process Consumables and Critical Chemicals for the upstream view.

Why Deposition Is Growing as a Share of Fab Capex

Transistor architecture evolution has concentrated new process complexity in deposition. The transition from planar MOSFET to FinFET added roughly 10 new deposition steps per layer; the transition from FinFET to gate-all-around (GAA) at 2nm and below adds another 15 to 20, because the nanosheet channels must be surrounded by high-k and metal gate materials deposited through ALD on all sides. 3D NAND scaling from 64 layers to 232+ layers has quintupled the number of deposition passes in the memory stack. Backside power delivery (introduced at Intel 18A) adds an entirely new set of deposition steps on the wafer backside.

The net effect is that deposition's share of WFE capex has grown relative to lithography over the past decade, and ALD specifically has grown faster than any other deposition method. ASM International's revenue trajectory reflects this directly — the ALD leader has outpaced overall WFE growth multiple years running. The trend continues through the 2nm and sub-2nm generations, where ALD-dependent structures (GAA gate stacks, advanced interconnect barriers, 3D memory) continue to expand.

Related Coverage

Parent: Front-End Fabrication

Peers in front-end: Wafer Cleaning · Oxidation · Photolithography · Etching · Doping · CMP · Metallization · Metrology

Equipment & consumables: WFE Hub · Process Consumables · Critical Chemicals · Process Gases

Cross-pillar dependencies: Process Nodes & Lines · Memory & Storage · SiC & GaN Power Modules · Bottleneck Atlas