In chip cleaning agents, the function of film-forming agents is to enhance cleaning effectiveness and prevent secondary contamination by forming a uniform protective film on the chip surface. The following are its core functions and technical principles:
01
Core Functions of Film Agents in Chip Cleaners
(1) Anti-corrosion Protection
Metal Layer Protection: After cleaning, metals on the chip surface (such as Al, Cu) may be exposed to air and undergo oxidation or corrosion. Film-forming agents (e.g., silane coupling agents, benzotriazole) can form an inert thin film that isolates oxygen and moisture, suppressing metal corrosion.
Example: BTA (benzotriazole) is used for anti-discoloration treatment of copper interconnect structures, forming a dense organic film.
(2) Anti-particle Adhesion
Surface Energy Reduction: Film-forming agents alter the surface properties of the chip through chemical bonding (e.g., silane reacting with Si-OH) or physical adsorption, changing it from hydrophilic to hydrophobic, thereby reducing the adhesion of particles (e.g., SiO₂, photoresist residues).
Example: Fluorosilanes (e.g., FDTS) form a low surface energy film after hydrofluoric acid cleaning to prevent particle redeposition.
(3) Enhanced Lubricity
Friction Damage Reduction: After chemical mechanical polishing (CMP), film-forming agents can repair microscopic surface scratches and reduce the risk of mechanical wear during subsequent processes (e.g., testing, packaging).
Example: Long-chain silanes (e.g., octadecyltrichlorosilane) form a molecular-level lubricating layer.
(4) Stabilized Cleaning Effect
Extended Cleanliness Duration: Film-forming agents can delay secondary adsorption of contaminants after cleaning. For instance, after RCA cleaning, silane films can maintain surface cleanliness for several hours, preventing contamination during storage.
02
Technical Principles of Film Agents
Chemical Bonding Mechanism:
Silane-based film-forming agents: Undergo hydrolysis to generate Si-OH, which condenses with hydroxyl groups (Si-OH) on the chip surface to form covalent Si-O-Si bonds, achieving chemical adsorption.
Reaction:
Si-CH₂CH₂CH₂Si(OH)₃ → Si-O-Si (on chip surface) + H₂O
Phosphate-based film-forming agents: Form stable chelate films by coordinating with metal oxides (e.g., Al₂O₃).
Physical Barrier Mechanism:
Polymer film-forming agents (e.g., polydimethylsiloxane): Spread into continuous films via van der Waals forces, filling surface microvoids to block contaminant penetration.
03
Application Scenarios
Post-wet cleaning treatment: After SC1/SC2 cleaning, silane film-forming agents (e.g., HMDS) are used to prevent oxidation caused by residual moisture.
Etching/Polishing protection: After CMP, fluorosilane films are sprayed to prevent contamination from dicing fluids.
Temporary storage protection: During wafer transport or testing, film-forming agents provide short-term (several hours to days) anti-contamination protection.
04
Precautions
Compatibility: Must not react adversely with cleaning agents (e.g., hydrofluoric acid, ozone water). For example, avoid silane hydrolysis failure under alkaline conditions.
Thickness Control: Film thickness is typically at the nanometer scale (e.g., 1–5 nm); excessive thickness may cause photolithography alignment errors or degrade electrical performance.
Removability: Must be easily removable before subsequent processes (e.g., bonding, metal deposition), typically via UV decomposition or solvent cleaning.
Disclaimer:
- This channel does not make any representations or warranties regarding the availability, accuracy, timeliness, effectiveness, or completeness of any information posted. It hereby disclaims any liability or consequences arising from the use of the information.
- This channel is non-commercial and non-profit. The re-posted content does not signify endorsement of its views or responsibility for its authenticity. It does not intend to constitute any other guidance. This channel is not liable for any inaccuracies or errors in the re-posted or published information, directly or indirectly.
- Some data, materials, text, images, etc., used in this channel are sourced from the internet, and all reposts are duly credited to their sources. If you discover any work that infringes on your intellectual property rights or personal legal interests, please contact us, and we will promptly modify or remove it.
