Application of HMDS Pre-Treatment Vacuum Oven in the Semiconductor Industry

In the semiconductor manufacturing field, lithography is a key process for the precise transfer of integrated circuit patterns, and the adhesion between photoresist and silicon wafers or other substrates is crucial for lithography quality. The HMDS pre-treatment vacuum oven enhances the adhesion between photoresist and the substrate by forming an HMDS bottom film on the surface of the silicon wafer, thereby improving lithography quality. The specific process involves first evacuating the vacuum chamber and then filling it with nitrogen gas, repeating this cycle to reduce the moisture on the surface of the silicon wafer. Subsequently, the wafer is heated to further remove moisture. HMDS gas is then introduced, which reacts with the surface of the silicon wafer to produce siloxane, changing the surface from hydrophilic to hydrophobic. Finally, the chamber is evacuated and filled with nitrogen gas again to complete the pre-treatment process.

Ⅰ. Working Principle of HMDS Pre-Treatment Vacuum oven

HMDS (hexamethyldisilazane) is a chemical substance used in semiconductor manufacturing to improve the surface characteristics of substrates. Its core function is to form an HMDS bottom film on the surface of materials such as silicon wafers, thereby enhancing the adhesion between photoresist and the substrate. The working process of the HMDS pre-treatment vacuum oven is as follows:

1. Vacuum and Nitrogen Purging: The vacuum chamber is first evacuated to achieve a high vacuum level. After that, nitrogen gas is introduced. This cycle of evacuation and nitrogen purging is repeated to reduce the moisture on the surface of the silicon wafer, creating favorable conditions for the subsequent HMDS treatment.

2. Heating and Dehydration: Once the set number of nitrogen purging cycles is reached, the silicon wafer is heated within the chamber to further remove moisture.

3. Reaction and Coating:After another evacuation, HMDS gas is introduced. Within a set time, the HMDS gas reacts fully with the silicon wafer, generating siloxane on the surface of the wafer. This reaction changes the surface from hydrophilic to hydrophobic, and the hydrophobic groups can effectively bond with the photoresist.

4. Exhaust Treatment:After the reaction is complete, the chamber is evacuated and filled with nitrogen gas again to finish the entire pre-treatment process. Excess HMDS vapor is drawn out by the vacuum pump and discharged into a dedicated exhaust gas collection pipeline for treatment.

Ⅱ. Technical Features of HMDS Pre-Treatment Vacuum Oven

● -Enhanced Adhesion of Photoresist: By uniformly coating HMDS on the surface of the silicon wafer, the contact angle of the wafer after pre-treatment is significantly reduced, changing the surface from hydrophilic to hydrophobic. This greatly enhances the adhesion between the photoresist and the silicon wafer, reducing defects in the lithography process caused by poor adhesion, such as pattern drifting and floating resist. This improves the success rate of pattern transfer in lithography and, consequently, the product yield.

● Reduced Photoresist Consumption: Since the HMDS treatment improves the adhesion between the silicon wafer and the photoresist, the photoresist can be more evenly coated on the surface of the wafer. Under the premise of ensuring lithography quality, the amount of photoresist used can be reduced, thereby effectively lowering production costs.

● Automation and Precise Control: The oven is equipped with a PLC industrial control automation system and a touch screen interface, which enhances the convenience of human-machine interaction and the reliability of operation. The PLC microcomputer PID control system can automatically control temperature and timing and has an over-temperature alarm function to ensure the precise execution of process parameters. Users can also flexibly adjust the program, temperature, vacuum level, and processing time through the touch screen control system according to different process conditions to meet diverse production needs.

Ⅲ. Application Fields of HMDS Pre-Treatment Vacuum Oven in the Semiconductor Industry

● Chip R & D and Manufacturing:In the front-end processing of chip manufacturing, the HMDS pre-treatment vacuum oven is one of the key pieces of equipment. It provides high-quality surface pre-treatment for the lithography process in chip manufacturing, ensuring the precision and performance of chip manufacturing. In the chip R & D stage, it offers a controllable experimental environment for R & D personnel, which is conducive to testing and optimizing the surface treatment effects of various materials and promoting the innovation and development of chip technology.

● Compound Semiconductor Production: For compound semiconductor materials such as gallium arsenide and gallium nitride, the adhesion problem between these materials and photoresist is more prominent. The HMDS pre-treatment vacuum ovencan effectively enhance the adhesion between these special materials and photoresist, solving the difficulties in traditional processes and playing an important role in the production of compound semiconductors.

● Display Device Processing:In the processing of display products such as electrowetting display devices, surface treatment of materials like silicon-based substrates is required. The HMDS pre-treatment vacuum oven can perform hydrophobic treatment on the surface of the dielectric layer, meeting the process requirements of display device manufacturing and improving the performance and quality of display devices.

As an indispensable key piece of equipment in semiconductor manufacturing, the HMDS pre-treatment vacuum oven effectively solves the problem of poor adhesion between photoresist and silicon wafers or other substrates through its unique process and excellent performance. It significantly improves the quality and efficiency of the lithography process. In fields such as chip R & D and manufacturing, compound semiconductor production, and display device processing, the HMDS pre-treatment vacuum oven has demonstrated its irreplaceable value.