WO2018086300A1

WO2018086300A1 - Method for forming slanting face at surface of substrate

Info

Publication number: WO2018086300A1
Application number: PCT/CN2017/078831
Authority: WO
Inventors: 丁刘胜
Original assignee: 上海新微技术研发中心有限公司
Priority date: 2016-11-14
Filing date: 2017-03-30
Publication date: 2018-05-17
Also published as: CN108069388B; CN108069388A

Abstract

A method for forming a slanting face at a surface of a substrate comprises: employing a size change of a material in an oxidization process to cause a flat face to slant with respect to a surface of a substrate (200), thereby forming a slanting face (208). An angle of the slanting face (208) is controllable. The slanting face (208) has favorable flatness.

Description

Method of forming a bevel on the surface of a substrate

Technical field

The present application relates to the field of semiconductor manufacturing technology, and more particularly to a method of forming a bevel structure on a surface of a substrate.

Background technique

In the manufacturing process of microelectromechanical systems (MEMS) devices, it is sometimes necessary to form a bevel pattern to fabricate optical devices, magnetic devices, and the like. Conventional methods, for example, may be to use a slope of an etched pattern to create a bevel.

It should be noted that the above description of the technical background is only for the purpose of facilitating a clear and complete description of the technical solutions of the present application, and is convenient for understanding by those skilled in the art. The above technical solutions are not considered to be well known to those skilled in the art simply because these aspects are set forth in the background section of this application.

Application content

The inventors of the present application found that in the method of manufacturing a slope using the slope of the etched pattern, it is difficult to control the flatness of the slope and the angle of the slope.

The present application provides a method for forming a bevel on the surface of a substrate, which utilizes a change in the size of the material during oxidation to tilt the plane relative to the surface of the substrate, thereby forming a bevel having a controllable tilt angle, and having a flatness of the bevel , the problem of the prior art is well solved.

According to an aspect of an embodiment of the present application, there is provided a bevel formed on a surface of a substrate The method, the inclined surface is inclined with respect to a surface of the base body, wherein the method comprises:

Forming a first support pillar and a second support pillar on a surface of the base body, the constituent material of the first support pillar is different from the constituent material of the second support pillar;

Forming a sacrificial layer surrounding the first support pillar and the second support pillar on a surface of the base body, the first support pillar being exposed from an upper surface of the sacrificial layer, and the upper side of the first support pillar The surface is equal to or higher than the upper surface of the sacrificial layer;

Forming a buffer layer and a bevel layer region on the upper surface of the sacrificial layer and the upper surface of the first support post, the first support post and the second support post being located below the bevel layer region;

Forming a release through hole penetrating the buffer layer outside the bevel layer region, and removing all the sacrificial layers under the bevel layer region through the release through hole to be used by the first support column and the The second support post supports the bevel layer region and the buffer layer below the bevel layer region;

Oxidizing the second support column to change the height of the second support column such that the bevel layer region is inclined with respect to a surface of the substrate, wherein an upper surface of the bevel layer region forms the Beveled.

Another aspect in accordance with an embodiment of the present application:

The angle at which the bevel layer region is inclined relative to the surface of the substrate is related to the extent to which the second support post is oxidized.

Another aspect in accordance with an embodiment of the present application:

The heights of the first support column and the second support column are the same or different.

Another aspect in accordance with an embodiment of the present application:

The constituent material of the first support pillar includes silicon nitride, and the constituent material of the second support pillar includes silicon.

According to another aspect of the embodiments of the present application, forming the first support pillar and the second support pillar on the surface of the base body includes:

Forming a first support pillar material layer on the surface of the substrate;

Etching the first support pillar material layer to form the first support pillar;

Forming a second layer of support pillar material on the surface of the substrate and the surface of the first support post;

The second pillar material layer is etched to form the second pillar.

Another aspect in accordance with an embodiment of the present application:

The material of the sacrificial layer includes silicon oxide, and the sacrificial layer is removed using hydrogen fluoride.

Another aspect in accordance with an embodiment of the present application:

The material of the buffer layer includes silicon nitride.

According to another aspect of the embodiments of the present application, the method further includes:

Forming a protective layer on a surface of the bevel layer region before forming the release via;

After the second support column is oxidized, the protective layer is removed to expose the slope.

The beneficial effects of the present application are that a slope with a controllable tilt angle can be formed, and the flatness of the slope is high.

Specific embodiments of the present application are disclosed in detail with reference to the following description and accompanying drawings, in which <RTIgt; It should be understood that the embodiments of the present application are not limited in scope. The embodiments of the present application include many variations, modifications, and equivalents within the scope of the appended claims.

Features described and/or illustrated with respect to one embodiment may be the same or similar parties The formula is used in one or more other embodiments, in combination with, or in place of, features in other embodiments.

It should be emphasized that the term "comprising" or "comprises" or "comprising" or "comprising" or "comprising" or "comprising" or "comprises"

DRAWINGS

The drawings are included to provide a further understanding of the embodiments of the present application, and are intended to illustrate the embodiments of the present application Obviously, the drawings in the following description are only some of the embodiments of the present application, and those skilled in the art can obtain other drawings according to the drawings without any inventive labor. In the drawing:

1 is a schematic view showing a method of forming a slope on a surface of a substrate in the embodiment of the present application;

2 is a schematic view showing a process flow of a method of forming a slope on a surface of a substrate in the embodiment of the present application.

detailed description

The foregoing and other features of the present application will be apparent from the description, The specific embodiments of the present application are specifically disclosed in the specification and the drawings, which illustrate a part of the embodiments in which the principles of the present application may be employed, it being understood that the present application is not limited to the described embodiments, but instead The application includes all modifications, variations and equivalents falling within the scope of the appended claims.

Example 1

Embodiment 1 of the present application provides a method of forming a bevel on a surface of a substrate that is inclined with respect to a surface of the substrate.

1 is a schematic view showing a method of forming a slope on a surface of a substrate in the embodiment of the present application. As shown in FIG. 1, the method includes:

Step 101: forming a first support pillar and a second support pillar on a surface of the base body, wherein a composition material of the first support pillar is different from a constituent material of the second support pillar;

Step 102, forming a sacrificial layer surrounding the first support pillar and the second support pillar on a surface of the base body, the first support pillar is exposed from an upper surface of the sacrificial layer, and the first support The upper surface of the pillar is equal to or higher than the upper surface of the sacrificial layer;

Step 103: sequentially forming a buffer layer and a bevel layer region on an upper surface of the sacrificial layer and an upper surface of the first support post, where the first support post and the second support post are located in the bevel layer region Below

Step 104, forming a release through hole penetrating the buffer layer outside the bevel layer region, and removing all the sacrificial layers under the bevel layer region through the release through hole to be the first support a column and the second support column support the bevel layer region and the buffer layer under the bevel layer region;

Step 105, performing oxidation treatment on the second support column to change the height of the second support column, so that the bevel layer region is inclined with respect to the surface of the substrate, wherein the upper surface of the bevel layer region The slope is formed.

According to the present embodiment, the change in the size of the second support column during the oxidation can be utilized such that the plane supported by the first support post and the second support post is inclined with respect to the surface of the base body, thereby forming a slope having a predetermined inclination angle. And the flatness of the slope is higher.

In this embodiment, the substrate may be a substrate commonly used in the field of semiconductor fabrication, such as a silicon wafer, a silicon-on-insulator (SOI) wafer, a silicon germanium wafer, or gallium nitride (Gallium). Nitride, GaN) wafers, etc.; and, the wafer It may be a wafer that has not been subjected to a semiconductor process, or a wafer that has been processed, such as a wafer that has been subjected to ion implantation, etching, and/or diffusion processes, which is not limited in this embodiment. .

In this embodiment, the constituent materials of the first support pillar and the constituent materials of the second support pillar may be different. For example, the constituent material of the first support pillar may include silicon nitride; and the constituent material of the second support pillar may include silicon. For example, polysilicon, single crystal silicon or amorphous silicon.

In this embodiment, the heights of the first support column and the second support column may be the same or different.

In this embodiment, the above step 101 can be implemented by the following steps, so that the first support column and the second support column are formed on the surface of the base body:

Step 1011, forming a first support pillar material layer on the surface of the substrate;

Step 1012: etching the first support pillar material layer to form the first support pillar;

Step 1013, forming a second support pillar material layer on the surface of the substrate and the surface of the first support pillar;

Step 1014, etching the second support pillar material layer to form the second support pillar.

Of course, the above steps 1011-1014 are only examples, and the embodiment is not limited thereto, and the first support column and the second support column may be formed in other manners.

In this embodiment, the material of the sacrificial layer may include silicon oxide, and the sacrificial layer may be removed using hydrogen fluoride in step 104. The embodiment may not be limited thereto, and the sacrificial layer may be other materials, and the sacrificial layer may be removed by the core material in a manner corresponding to the material of the sacrificial layer in step 104.

In this embodiment, the material of the buffer layer may include silicon nitride, which has greater elasticity and can accommodate a greater degree of strain. In addition, other materials may be used to form the buffer layer.

In this embodiment, the material of the bevel layer region may comprise silicon. In addition, it can also be made Other materials are used to form the bevel layer region.

In the step 105 of the embodiment, the height of the first support column does not change, and the oxidation of the second support column causes the height of the second support column to change, and therefore, the inclined layer supported by the second support column One side of the region is raised such that the bevel layer region is inclined with respect to the surface of the substrate, whereby the upper surface of the bevel layer region forms the slope.

As shown in FIG. 1 , in this embodiment, the method may further include:

Step 106, forming a protective layer on a surface of the bevel layer region before forming the release via hole;

Step 107: After the second support column is oxidized, the protective layer is removed to expose the slope.

Wherein, step 106 may be before step 104 for forming a protective layer to protect the bevel layer region during the step of removing the sacrificial layer in step 104; step 107 may be after step 105 to remove the protective layer covering the bevel layer region, Thereby the slope of the bevel layer area is exposed.

With the present embodiment, it is possible to utilize the change in the size of the second support column during the oxidation process such that the plane supported by the first support post and the second support post is inclined with respect to the surface of the base body, thereby forming a slope having a predetermined inclination angle. And the flatness of the slope is higher.

Next, a method of forming a slope of the present embodiment will be described with reference to specific examples.

In this specific example, the constituent material of the first support pillar may be, for example, silicon nitride, the constituent material of the second support pillar may be, for example, silicon, the material of the sacrificial layer may be silicon oxide, and the material of the buffer layer may be, for example, nitridation. The material of the silicon, bevel layer region may for example be silicon.

2 is a schematic diagram of a process flow for forming a slope according to an embodiment of the present application. As shown in FIG. 2, the process includes:

1) depositing a layer of silicon nitride (SiN) material 201a on the substrate 200, the substrate 200 For example, it may be a base wafer.

2) The first support pillar 201 is formed by photolithography, etching, and degumming processes.

3) A silicon material 202a is deposited on the substrate 200, and polysilicon, single crystal silicon or amorphous silicon may be deposited as needed.

4) A second support pillar 202 is formed by photolithography, etching, and degumming processes.

5) depositing a sacrificial layer 203, which may be, for example, silicon oxide, and may generally cover BPSG, PSG, SOG, etc. to form the silicon oxide.

6) Polishing the surface uneven silicon oxide by chemical mechanical polishing (CMP) or the like to expose the first support pillar 201 and the second support pillar 202.

7) depositing a silicon nitride layer as a buffer layer 204 on the surfaces of the first support pillar, the second support pillar, and the sacrificial layer, and then depositing a silicon material layer as a bevel material layer 205a of a predetermined thickness, the silicon material layer For example, it may be polycrystalline silicon, single crystal silicon or amorphous silicon.

8) A bevel layer region 205 is formed in the bevel material layer 205a by photolithography, etching, and de-glue processes.

9) Depositing a layer of silicon nitride as a protective layer 206, which may cover the upper surface and sides of the bevel layer region 205.

10) In the region outside the bevel layer region 205, the position of the release via is defined by photolithography, etching and de-glue process, and the buffer layer 204 is etched to form the release via 207, and the via etching remains The base wafer 200 is on the substrate.

11) The sacrificial layer 203 is removed by etching using hydrogen fluoride HF gas.

12) Oxidation by the diffusion furnace tube causes the second support column 202 to be oxidized to 212, resulting in a change in size such that the facer layer region 205 is inclined with respect to the surface of the base wafer 200.

13) Using a dry etch, the silicon nitride protective layer 206 on the surface of the surface bevel layer region 205 is removed, exposing the surface of the bevel layer region 206, which surface becomes a bevel 208.

As shown in 13) of FIG. 2, assuming that the height of the first support column 201 is a, the original height of the second support column is also a, and the second support column 202 after the oxidation treatment is all converted into silicon oxide, and the height thereof becomes 2.27a, the distance between the first support column and the second support column is b, whereby the angle θ of the slope 208 with respect to the base silicon wafer 200 is θ=actg(1.27a/b), so that the slope can be accurately controlled with respect to The angle of inclination of the surface of the substrate.

Further, by setting a, b, and the time of the oxidation treatment, it is possible to control the inclination angle of the slope 208 with respect to the surface of the base.

In the present embodiment, the flatness of the bevel 208 is related to the process of depositing the silicon material, so that a higher flatness can be obtained.

The present invention has been described in connection with the specific embodiments thereof, but it is to be understood that the description is intended to be illustrative and not restrictive. Various modifications and alterations of the present application are possible in light of the spirit and scope of the invention, which are also within the scope of the present application.

Claims

A method of forming a bevel on a surface of a substrate, the bevel being inclined with respect to a surface of the substrate, wherein the method comprises:

Forming a first support pillar and a second support pillar on a surface of the base body, the constituent material of the first support pillar is different from the constituent material of the second support pillar;

Forming a sacrificial layer surrounding the first support pillar and the second support pillar on a surface of the base body, the first support pillar being exposed from an upper surface of the sacrificial layer, and the upper side of the first support pillar The surface is equal to or higher than the upper surface of the sacrificial layer;

Forming a buffer layer and a bevel layer region on the upper surface of the sacrificial layer and the upper surface of the first support post, the first support post and the second support post being located below the bevel layer region;

Forming a release through hole penetrating the buffer layer outside the bevel layer region, and removing all the sacrificial layers under the bevel layer region through the release through hole to be used by the first support column and the The second support post supports the bevel layer region and the buffer layer below the bevel layer region;

Oxidizing the second support column to change the height of the second support column such that the bevel layer region is inclined with respect to a surface of the substrate, wherein an upper surface of the bevel layer region forms the Beveled.
A method of forming a bevel on a surface of a substrate according to claim 1, wherein

The angle at which the bevel layer region is inclined relative to the surface of the substrate is related to the extent to which the second support post is oxidized.
A method of forming a bevel on a surface of a substrate according to claim 1, wherein

The heights of the first support column and the second support column are the same or different.
A method of forming a bevel on a surface of a substrate according to claim 1, wherein

The constituent material of the first support pillar includes silicon nitride, and the constituent material of the second support pillar includes silicon.
A method of forming a bevel on a surface of a substrate according to claim 1, wherein forming a first support post and a second support post on a surface of the substrate comprises:

Forming a first support pillar material layer on the surface of the substrate;

Etching the first support pillar material layer to form the first support pillar;

Forming a second layer of support pillar material on the surface of the substrate and the surface of the first support post;

The second pillar material layer is etched to form the second pillar.
A method of forming a bevel on a surface of a substrate according to claim 1, wherein

The material of the sacrificial layer includes silicon oxide, and the sacrificial layer is removed using hydrogen fluoride.
A method of forming a bevel on a surface of a substrate according to claim 1, wherein

The material of the buffer layer includes silicon nitride.
The method of forming a bevel on a surface of a substrate according to claim 1, wherein the method further comprises:

Forming a protective layer on a surface of the bevel layer region before forming the release via;

After the second support column is oxidized, the protective layer is removed to expose the slope.