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CN-122003138-A - Preparation method of low-loss semiconductor power device substrate

CN122003138ACN 122003138 ACN122003138 ACN 122003138ACN-122003138-A

Abstract

The invention discloses a preparation method of a low-loss semiconductor power device substrate, which comprises the following steps of taking at least two silicon wafer bodies as a group, oxidizing at least one of the silicon wafer bodies, carrying out treatment and cleaning on the silicon wafer bodies, sequentially stacking and bonding the silicon wafer bodies into a combined silicon wafer, forming oxide layers on at least one surface, which is close to each other, of the two adjacent silicon wafer bodies, wherein the oxide layers at two ends of the combined silicon wafer are required to be removed before treatment and cleaning, removing the oxide layers on the non-bonding surface of the combined silicon wafer, carrying out deep-bonding pre-deposition and pushing treatment on the combined silicon wafer, soaking the combined silicon wafer in hydrofluoric acid, carrying out weak sand blowing treatment on the non-diffusion surface of the diffused silicon wafer, and carrying out ultrasonic cleaning and spin-drying on the diffused silicon wafer.

Inventors

  • CAO SUNGEN

Assignees

  • 安徽微半半导体科技有限公司

Dates

Publication Date
20260508
Application Date
20231228

Claims (8)

  1. 1. The preparation method of the low-loss semiconductor power device substrate is characterized by comprising the following steps of: Step one, taking at least two silicon wafer bodies as a group, and oxidizing at least one of the silicon wafer bodies; Step two, firstly, processing and cleaning each silicon wafer body, and then sequentially stacking and bonding each silicon wafer body into a combined silicon wafer; Step three, removing an oxide layer on the non-bonding surface of the bonded silicon wafer, and then treating and cleaning the bonded silicon wafer; step four, performing deep junction pre-deposition and propulsion treatment on the combined silicon wafer; step five, soaking the combined silicon wafer by hydrofluoric acid, separating the combined silicon wafer into two diffusion silicon wafers, and then flushing the diffusion silicon wafers by clean water and deionized water; and step six, carrying out weak sand blasting treatment on the non-diffusion surface of the diffusion silicon wafer, and then carrying out ultrasonic cleaning and spin-drying on the diffusion silicon wafer.
  2. 2. The method of manufacturing a low-loss semiconductor power device substrate according to claim 1, wherein in the first step, the thickness, resistivity and crystal orientation of the two silicon wafer bodies are the same.
  3. 3. A method of manufacturing a low loss semiconductor power device substrate according to claim 1, wherein in step six, the weak blowing is performed to remove a thickness of 2-5 UM.
  4. 4. The method of claim 1, wherein in the third step, the removing method of the redundant oxide layer is one of photoresist assisted wet etching, UV film assisted wet etching and sand blowing.
  5. 5. The method for manufacturing a low-loss semiconductor power device substrate according to claim 4, wherein in the third step, when the method for removing the excess oxide layer is a photoresist-assisted method combined with wet etching, the end face of the excess oxide layer of the silicon wafer body is masked with photoresist, then the oxide layer of the non-bonding surface is removed with hydrofluoric acid, then the wafer is rinsed with deionized water, then dried, and then the photoresist is removed by heating the mixture with sulfuric acid and hydrogen peroxide.
  6. 6. The method of manufacturing a low-loss semiconductor power device substrate according to claim 4, wherein in the third step, when the method of removing the excess oxide layer is a UV film-assisted method combined with wet etching, the end face of the excess oxide layer of the silicon wafer body is masked with a UV film, then the oxide layer of the non-bonding face is removed with hydrofluoric acid, then rinsed with deionized water, then spin-dried, and then irradiated with UV to lose the adhesiveness of the film, and the silicon wafer body is detached from the UV film.
  7. 7. The method for manufacturing a low-loss semiconductor power device substrate according to claim 4, wherein in the third step, when the method for removing the unnecessary oxide layer is sand blasting, the oxide layer of the non-bonding surface is blasted with 300-700 mesh powder material, then the powder material on the silicon wafer is ultrasonically cleaned with a cleaning agent, and then the silicon wafer is rinsed with ionized water and dried, wherein the powder material is one of garnet corundum powder and silicon carbide powder.
  8. 8. The method for manufacturing a low-loss semiconductor power device substrate according to claim 1, wherein in the second and third steps, the method for processing cleaning is one of a distribution method and a direct method, the distribution method is plasma etching cleaning and wet cleaning, and the direct method is wet cleaning.

Description

Preparation method of low-loss semiconductor power device substrate Technical Field The invention relates to the technical field of substrate preparation, in particular to a method for preparing a low-loss semiconductor power device substrate. Background In the prior art, a silicon wafer with higher cost and thicker thickness is generally adopted for cleaning, deep junction pre-deposition and pushing to prepare a high-concentration substrate, then the other surface of the substrate (namely, the inversion layer caused by high concentration diffusion vapor pressure) is removed by a sand blasting or lapping mode, under the condition that the air flow control of a compression process technology or a diffusion gas component is better, the inversion layer still needs to reach 2/3 or more of a diffusion junction, and the method has the other problem that the high concentration diffusion is on one surface, after the diffusion impurities fill the edge of the surface level back of the silicon wafer, the lattice extrusion causes unidirectional deformation (namely, the silicon wafer warps), and fragments in the sand blasting or lapping process are easily caused. Disclosure of Invention The invention aims to solve the problems in the prior art: The inversion layers of the silicon wafer are more in the existing method. The preparation method of the substrate of the low-loss semiconductor power device is provided. In order to achieve the above purpose, the present invention adopts the following technical scheme: A preparation method of a low-loss semiconductor power device substrate comprises the following steps: Step one, taking at least two silicon wafer bodies as a group, and oxidizing at least one of the silicon wafer bodies; Step two, firstly, processing and cleaning each silicon wafer body, and then sequentially stacking and bonding each silicon wafer body into a combined silicon wafer; Step three, removing an oxide layer on the non-bonding surface of the bonded silicon wafer, and then treating and cleaning the bonded silicon wafer; step four, performing deep junction pre-deposition and propulsion treatment on the combined silicon wafer; step five, soaking the combined silicon wafer by hydrofluoric acid, separating the combined silicon wafer into two diffusion silicon wafers, and then flushing the diffusion silicon wafers by clean water and deionized water; and step six, carrying out weak sand blasting treatment on the non-diffusion surface of the diffusion silicon wafer, and then carrying out ultrasonic cleaning and spin-drying on the diffusion silicon wafer. As a further technical scheme of the invention, in the first step, the thickness, the resistivity and the crystal orientation of the two silicon wafer bodies are the same. As a further technical scheme of the invention, in the step six, the thickness of 2-5UM is removed by weak sand blowing. As a further technical scheme of the invention, in the third step, the method for removing the redundant oxide layer is one of a photoresist auxiliary method combined with wet etching, a UV film auxiliary method combined with wet etching and sand blowing. In the third step, when the method for removing the redundant oxide layer is a photoresist auxiliary method combined with wet etching, masking the end face of the redundant oxide layer of the silicon wafer body by using photoresist, then removing the oxide layer of the non-bonding surface by using hydrofluoric acid, then washing by using deionized water, then drying, and then heating the mixed solution by using sulfuric acid and hydrogen peroxide to remove the photoresist. In the third step, when the method for removing the redundant oxide layer is a combination of a UV film auxiliary method and wet etching, the end face of the redundant oxide layer of the silicon wafer body is shielded by the UV film, then the oxide layer of the non-bonding surface is removed by hydrofluoric acid, then deionized water is used for washing, then spin-drying is carried out, and then UV is irradiated to enable the film to lose viscosity, so that the silicon wafer body is separated from the UV film. In the third step, when the method for removing the redundant oxide layer is sand blowing, the 300-700 mesh powder material is used for blowing the oxide layer of the non-bonding surface, then the cleaning agent is used for ultrasonically cleaning the powder material on the silicon wafer, then the ion water is used for flushing and spin-drying, and the powder material is one of garnet corundum powder and silicon carbide powder. As a further technical scheme of the invention, in the second and third steps, the method of treatment cleaning is one of a distribution method and a direct method, the distribution method is plasma etching cleaning and wet cleaning, and the direct method is wet cleaning. The invention has the beneficial effects that: The invention combines two silicon wafers through silicon dioxide interface bonding, no gap exists between