Wafer Manufacturing Process: From Silicon Refining to Integrated Circuits

A wafer is a silicon wafer used to manufacture silicon semiconductor integrated circuits.wafer testing It is called a wafer because of its circular shape. Various circuit element structures can be fabricated on the silicon chip, thus becoming an integrated circuit product with specific electrical performance functions.

The main raw material for semiconductor integrated circuits is silicon, so the corresponding silicon wafer. Silicon is widely available in nature in the form of silicate or silicon dioxide in rocks and gravel. The manufacture of silicon wafers can be summarized in three basic steps: silicon refining and purification, single crystal silicon growth and wafer forming.

The manufacturing process is as follows:

1. Surface Cleaning: A protective layer consisting of a mixture of approximately 2um Al2O3 and glycerin is attached to the wafer surface. Chemical etching and surface cleaning must be performed prior to fabrication.

2. Initial oxidation: A buffer layer of SiO2 is generated by thermal oxidation, which is used to be able to reduce the stress of Si3N4 on the wafer in the follow-up of the company's oxidation treatment technology.

3. Thermal CVD: This teaching method carries on the productivity high, ladder laying good (no matter how uneven,wafer probe deep holes in the surface can also produce bad reaction, the gas can reach a surface and attached film), so the enterprise application research range is very wide.

4.  Heat Treatment: Before applying photoresist, an adhesive enhancer is applied to the surface of a clean substrate or the substrate is heat-treated by placing it under an inert gas. This is done to increase the adhesion between the photoresist and the substrate, to prevent the photoresist pattern from falling off during development, and to prevent side etching during wet etching.

5. The backside of the wafer grinding process: In order to reduce the thermal resistance of the device, improve the work of heat dissipation and cooling capacity, to facilitate packaging, the need to make integrated circuits on the front side of the wafer after the production of the back side of a thinner.probe holder The back grinding process of the wafer is to put a film on the front side of the wafer to protect the integrated circuits that have been made, and then use a grinder to make it thinner.

6. Silicon Nitride Removal: Here silicon nitride is removed by dry oxidation.

7. Ion implantation:Ion implantation is the injection of boron ions (B+3) through a SiO2 film into the substrate to form a P-trap. Ion implantation is a method of accelerating impurity ions into the silicon substrate with an electric field. Ion implantation is characterized by the ability to precisely control the distribution of low concentrations of impurities that are difficult to obtain by diffusion.