What are the advantages of welding and bending parts of resin materials in semiconductor field?
The application advantages of resin welded and bent parts in the semiconductor field need to be comprehensively analyzed from the aspects of material characteristics, processing technology and special requirements of the semiconductor industry (such as cleanliness, corrosion resistance, electrical insulation, etc.). The following are specific advantages and application scenarios:
First, the material characteristics adapt to the requirements of semiconductor environment
1. High cleanliness and low ion precipitation
Advantages:
It is necessary to control particle (≤0.1μm) and ion pollution (such as Na and Cl) in SEMIconductor manufacturing. Resin materials (such as PTFE and PEEK) are of high purity, and there is no metal ion residue on the surface after processing, which meets the semi standard (ion content ≤10ppm).
Application:
Cassette)：PEEK carrier is resistant to etching solution (such as HF), and friction does not produce metal chips, thus avoiding wafer scratch.
Clean room pipeline: PTFE pipeline has smooth inner wall (Ra≤0.2μm) and does not absorb pollutants, which is suitable for conveying ultra-pure water (resistivity ≥ 18m Ω cm).
2. Excellent chemical corrosion resistance
Advantages:
Resin materials have strong tolerance to strong acids (such as H₂SO₄), strong bases (such as KOH) and organic solvents (such as isopropanol IPA) in semiconductor technology, so as to avoid particle shedding or ion release caused by corrosion of metal materials.
Application:
Parts and components of etching equipment: fluororubber seal is not easy to age in NF plasma environment, and its service life is 3-5 times longer than that of metal seal.
Cleaning tank lining: PVDF (polyvinylidene fluoride) lining can withstand the cleaning process of aqua regia (HNO₃+HCL), and there is no corrosion trace on the surface.
3. Electrical insulation and low dielectric loss
Advantages:
The dielectric constant (ε≤4) and dielectric loss tangent (tanδ≤0.001) of the resin material are low, which avoids signal transmission interference, and at the same time, the insulation can prevent electrostatic discharge (ESD) from damaging the wafer.
Application:
Semiconductor package board: Epoxy resin-based copper clad laminate (FR-4) is used as IC package board, with low dielectric loss and suitable for high-frequency signal transmission.
Electrostatic protection tray: conductive resin tray with carbon nanotubes (surface resistance of 10-10 Ω), which can discharge static electricity and is not conductive to short circuit.
Second, the advantages of welding and bending process
1. Precision Forming and Complex Structure Processing
Advantages:
Resin materials can be formed with micron precision by hot welding (such as laser welding and hot plate welding) and cold bending (such as normal temperature molding) to avoid cutting burr or stress deformation in metal processing.
Application:
Microfluidic chip channel: PMMA (acrylic) forms micron-sized channel (width 50-100μm) by hot bending, which is used to distribute semiconductor cleaning solution, and the precision error is ≤ 5 μ m..
Multi-layer carrier bracket: PEI (polyetherimide) is used to splice multi-layer structures by ultrasonic welding, and the flatness is ≤0.02mm/100mm, which is suitable for wafer inspection equipment.
2. Metal-free connection process
Advantages:
Resin welding does not need flux (such as rosin in metal welding), which avoids residual pollution, and the welding heat affected zone is small (≤0.1mm) and does not change the molecular structure of the material.
Application:
Gas transmission pipeline joint: PFA (soluble polytetrafluoroethylene) is welded by hot melt to form seamless joint, and the leakage rate is ≤ 1× 10 PAM/s, which is suitable for conveying high-purity gases (such as N and Ar).
Insulating bracket of probe card: epoxy resin is bonded by UV glue, and the curing temperature is ≤80℃, which will not damage the electrical properties of probes (spacing ≤50μm).
3. Lightweight and fatigue resistance
Advantages:
The density of resin (1-2g/cm) is only 1/2-1/3 of that of metal (such as Al: 2.7g/cm), and the bending fatigue life (≥ 10 times) is higher than that of metal plate (such as stainless steel: 10 times), so it is suitable for high-frequency moving parts.
Application:
Wafer handling manipulator joint: POM (Polyoxymethylene) is a joint part formed by bending, which is 40% lighter than aluminum alloy, and the repeated positioning accuracy is ≤0.01mm, which is suitable for high-speed handling (speed ≥1m/s).
Radiator bracket: LCP (liquid crystal polymer) forms a hollow structure by hot bending, with heat dissipation efficiency 15% higher than that of metal bracket, and is resistant to cold and hot cycles (-40℃~125℃) without cracking.
Third, the advantages of scene in semiconductor technology
1. Wafer manufacturing process
Lithography process:
Resin light shielding plate: SU-8 photoresist forms micron-scale light shielding pattern (line width ≤1μm) through UV curing, and its accuracy is 30% higher than that of metal mask plate, which is suitable for advanced process (≤14nm).
Etching process:
Resin spray head: the spray hole (diameter 0.5-1mm) formed by bending PPS is resistant to Cl plasma corrosion, and the spray uniformity deviation is ≤ 3%.
2. Packaging test link
Flip Chip:
Resin substrate: BT resin (brominated epoxy resin) is laminated and bent to form a multilayer wiring substrate, and the thermal expansion coefficient (CTE≤15ppm/℃) is highly matched with the silicon chip (CTE=3ppm/℃), thus reducing thermal stress cracking.
Reliability test:
Resin test fixture: PC (polycarbonate) bending fixture slot, when the chip is pressed (≤5N), the deformation is ≤0.05mm to avoid test damage.
3. Equipment maintenance link
Corrosion resistant fittings:
Resin valve plate: ETFE (ethylene-tetrafluoroethylene copolymer) is made into valve sealing plate by thermal welding. After soaking in concentrated nitric acid at 150℃ for 1000 hours, the weight loss is ≤0.1%, which replaces metal valve plate to reduce maintenance cost (replacement frequency is reduced from once a month to once a year).
Fourth, the comparative advantages with metal materials
Comparative dimension resin material (such as peek) metal material (such as 316L stainless steel).
Cleanliness ion precipitation is less than or equal to 5 ppm, and no metal particles need electroplating for rust prevention after processing, and Cr⁶⁺ may remain.
Corrosion resistance Strong acid and alkali (such as aqua regia) have limited corrosion resistance and are easy to corrode in HF.
Machining accuracy: thermal welding accuracy: 5 μ m; bending fillet R ≥ 0.1 mm; cutting accuracy: 50 μ m; bending R ≥ 1 mm.
The cost of materials is high, but there are few processing procedures (such as no surface treatment). The cost of materials is low, but electroplating, polishing and other procedures are needed.
Weight density is 1.3g/cm³ and density is 7.9g/cm³.
V. Industry Standards and Certification Requirements
SEMI standard:
Resin parts shall be certified by SEMI F20 (Material Evaluation of Semiconductor Manufacturing Equipment), with particle release ≤100/ft (≥ 0.5 μ m) and ion content ≤ 1 ppm (Na, Cl, etc.).
Clean room grade:
When it is used in ISO 1 clean room (Class 1), the resin surface needs plasma treatment (such as O plasma etching), and the roughness Ra is less than 0.1 μ m to reduce particle adsorption.
Summary: the core advantage logic of resin materials
The application advantages of resin materials in the semiconductor field are essentially the triple matching of "material characteristics-process accuracy-environmental adaptation": the material characteristics with high purity and low ion precipitation meet the cleaning requirements, the precision molding and metal-free processing are realized by welding and bending process, and finally the metal materials are replaced in lithography, etching, packaging and other scenes to solve the problems of corrosion, pollution and accuracy. In the future, with the development of semiconductor manufacturing process to 3nm and below, the low dielectric and low thermal expansion characteristics of resin materials will further expand the application space (such as advanced packaging substrates and extreme ultraviolet lithography (EUV) equipment components).
