CN-116313752-B - Method for depositing carbon film on groove-type device and groove-type device

Abstract

The invention relates to the field of semiconductor manufacturing, and discloses a method for depositing a carbon film on a groove-shaped device and the groove-shaped device, wherein the method comprises the steps of spin-coating a photoresist layer on the surface of a wafer of the groove-shaped device to form a first wafer, depositing the first carbon film with the thickness of T 1 on the first wafer to form a second wafer, removing the photoresist layer and the carbon film layer deposited on the surface of the second wafer to form a third wafer, depositing the second carbon film with the thickness of T 2 on the third wafer to form a target wafer, C is the step coverage rate of the groove type device. Through the twice carbon film deposition, the thicknesses of the carbon films on the wafer surface, the side wall and the bottom of the groove type device are the same, the same carbon protection capability is provided, and the consistency of the carbon film on the carbon protection capability of different positions of the groove type device is ensured.

Inventors

• ZHANG DONGHUA
• ZHU QIWEI
• LIU QIN
• WANG ZHICHENG
• CHENG YINHUA
• ZHAO YANLI
• PAN ZHAOHAI

Assignees

• 株洲中车时代半导体有限公司

Dates

Publication Date

20260505

Application Date

20230214

Claims (6)

1. 1. A method of depositing a carbon film for a trench device, the wafer of the trench device comprising a surface, trench sidewalls, and a trench bottom, comprising: Spin-coating a photoresist layer on the wafer surface of the groove type device to form a first wafer; Performing first carbon film deposition with the thickness of T 1 on the first wafer to form a second wafer; Removing the photoresist layer and the carbon film layer deposited on the surface of the second wafer to form a third wafer; And performing second carbon film deposition with the thickness of T 2 on the third wafer to form a target wafer, wherein, C is the step coverage rate of the groove type device.
2. 2. A method of depositing a carbon film in a trench device as defined in claim 1, wherein spin coating a photoresist layer on the wafer surface of the trench device comprises: Spin coating a layer of photoresist on the wafer surface of the groove type device; And processing the photoresist by using an exposure and development technology, and forming a chamfer photoresist layer on the wafer surface of the groove type device.
3. 3. The method of depositing a carbon film in a trench device of claim 2, wherein prior to the first carbon film deposition, the method further comprises: and stripping off the photoresist in the side wall and the bottom of the groove of the first wafer by adopting a Lift-off process.
4. 4. The method for depositing a carbon film in a trench device of claim 1, wherein the photoresist layer and the carbon film layer deposited on the surface of the second wafer are stripped and removed by a Lift-off process.
5. 5. The method of depositing a carbon film in a trench device of claim 1, wherein the first carbon film deposition and the second carbon film deposition are both performed by a normal temperature PVD carbon film sputtering technique.
6. 6. A trench device, comprising: A wafer substrate, a wafer surface, a trench sidewall and a trench bottom formed on the wafer surface by an etching process, and a carbon film deposited on the wafer surface, the trench sidewall and the trench bottom, wherein the carbon film is prepared by a method for depositing a carbon film by a trench device according to any one of claims 1 to 5.

Description

Method for depositing carbon film on groove-type device and groove-type device Technical Field The present invention relates to the field of semiconductor manufacturing, and more particularly, to a method for depositing a carbon film on a trench device and a trench device. Background SiC materials, as third generation semiconductor materials, have many advantageous properties such as high temperature, high pressure and radiation resistance, making SiC devices a distinct advantage over conventional devices, and are consistently considered to be the most potential semiconductor devices. But some unique properties of SiC materials also place new demands on their process manufacturing technology. Because the impurity diffusion coefficient of the SiC material is low, the ion implantation becomes the optimal method for the selective area doping of the SiC device. However, the impurity ions implanted into the SiC material are substantially at lattice gap positions, and in order to replace these impurity ions at lattice point positions, it is necessary to perform high-temperature activation annealing on the SiC material after ion implantation, where the annealing temperature is generally higher than 1400 ℃ for N-type impurities, and the P-type is 1600 ℃ to 1800 ℃. At such high annealing temperatures, silicon in the SiC may volatilize and redeposit, resulting in step clusters on the annealed wafer surface, resulting in poor wafer surface morphology, and thus severely affecting device performance. In order to solve the problem, a protective layer is covered on the surface of the SiC wafer during high-temperature activation annealing to inhibit volatilization and deposition of silicon. The carbon protective film is the most widely used at present, because carbon and SiC do not react at high temperature, and furthermore, the carbon protective film has certain hardness, can effectively inhibit silicon precipitation in SiC, and can be effectively removed by oxidation and other methods after high-temperature activation annealing, so that the performance of the device is not affected. In the prior art, the carbon film adopting PVD magnetron sputtering has effective protection on a planar SiC device, but for a SiC groove device, as the step coverage rate of the PVD sputtering carbon film on the groove is about 30%, the thickness difference of the carbon film on the side wall and the bottom of the groove and the SiC surface is larger, and the protection capability is greatly different (the protection capability of the carbon film is in a descending trend along with the thickness increase), as shown in figure 1. Therefore, how to ensure that the side wall, the bottom and the surface of the SiC trench device have the same carbon protection capability has become a technical problem to be solved. Disclosure of Invention The invention aims to provide a method for depositing a carbon film on a groove-shaped device, which ensures that the thickness of the carbon film deposited on the side wall, the bottom and the surface of the groove-shaped device is the same by performing carbon film deposition on the groove-shaped device twice, thereby having the same carbon protection capability and ensuring the consistency of the protection capability of the carbon film on different positions of the groove-shaped device. The aim of the invention is mainly achieved by the following technical scheme: In a first aspect, a method of depositing a carbon film for a trench device, a wafer of the trench device comprising a surface, trench sidewalls, and a trench bottom, the method comprising: Step 1, spin coating a photoresist layer on the surface of a wafer of the groove type device to form a first wafer; Step 2, performing first carbon film deposition with the thickness of T 1 on the first wafer to form a second wafer, wherein a photoresist layer and a first carbon film layer with the thickness of T 1 are deposited on the surface of the second wafer, and a second carbon film layer and a third carbon film layer with the thickness of T 1 x c are respectively deposited on the side wall and the bottom of a groove of the second wafer, wherein c is the step coverage rate of the groove type device; step 3, removing the photoresist layer and the first carbon film layer deposited on the surface of the second wafer to form a third wafer, wherein the third wafer is respectively deposited with a second carbon film layer and a third carbon film layer with the thickness of T 1 x c only on the side wall and the bottom of the groove; Step 4, performing second carbon film deposition with the thickness of T 2 on the third wafer to form a target wafer, wherein a fourth carbon film layer with the thickness of T 2 is deposited on the surface of the target wafer, the second carbon film layer and a fifth carbon film layer with the thickness of T 2 c are respectively deposited on the side wall of a groove of the target wafer, and the third carbon film layer and a sixth car