Wet etching separation method of wafer
Through the wet etching separation method, the wafer is separated by hydrofluoric acid or sodium hydroxide solution etching solution, which solves the problems of high stress and cost in the traditional method, and achieves higher yield and lower cost.
Patent Information
- Application Number
- CN202311387785.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-10-25
- Publication Date
- 2025-04-25
AI Technical Summary
Traditional wafer separation methods such as mechanical cutting and thermal cutting have problems such as high stress, residues and cutting costs, which leads to wafer prone to cracking and low yield.
By using wet etching and separation method, the mask is formed on the wafer surface and the marks are separated, and the etching solution is used to separate, so as to avoid stress caused by mechanical cutting or thermal cutting.
Effectively control the separation edge of semiconductor wafers, reduce the stress generated by semiconductors, reduce the risk of deformation and cracking, and improve the product yield, while being simple to operate and low cost.
Abstract
Description
Technical Field
[0001] The invention relates to the field of semiconductor manufacturing, and in particular to a wet etching separation method for wafers. Background Art
[0002] With the rapid advancement of semiconductor technology, the requirements for semiconductor manufacturing and processing are getting higher and higher. Separating wafers into required units is a necessary process for wafer processing. Traditional wafer separation methods include mechanical separation, thermal cutting, etc. However, these methods have problems, such as the impact of residues on the peeling surface, residual stress, and surface quality. For example, during mechanical separation, the semiconductor will be subjected to greater stress near the cutting path, which can easily cause edge cracking and wafer breakage. Thermal cutting, such as laser cutting, focuses a high-power laser on the surface of the wafer, causing the local temperature of the wafer to rise and decompose, but laser cutting has problems such as high cutting cost and the easy generation of microcracks at the cutting mouth.
[0003] Therefore, it is urgent to provide an improved wet etching separation method for wafers to overcome the above defects. Summary of the invention
[0004] The purpose of the present invention is to provide an improved wet etching separation method for wafers, which has low cost, simple operation, and avoids the stress and poor cutting effect caused by mechanical cutting or thermal cutting, thereby reducing the possibility of semiconductor wafer cracking and improving the product yield.
[0005] To achieve the above object, the wet etching separation method of the wafer of the present invention comprises the following steps:
[0006] A mask is formed on the surface of a wafer, and separation marks are formed on the wafer, wherein the mask protects the wafer and exposes the separation marks to the outside;
[0007] forming a photoresist on the mask; and
[0008] The wafer is immersed in an etching solution to separate the wafer along the separation marks, and the etching solution is a hydrofluoric acid solution or a sodium hydroxide solution.
[0009] Compared with the prior art, the present invention adopts a separation method of wet etching, firstly, a mask is formed on the surface of the wafer, a separation notch is formed on the wafer, the mask protects the wafer and exposes the separation notch; then, a photoresist is formed on the mask; the wafer is immersed in an etching solution of a hydrofluoric acid solution or a sodium hydroxide solution to separate the wafer along the separation notch. Compared with traditional mechanical cutting or thermal cutting, the present invention can effectively control the separation edge of the semiconductor wafer, greatly reduce the stress generated by the semiconductor on the semiconductor wafer, reduce the deformation of the semiconductor, thereby reducing the possibility of the semiconductor wafer from cracking, and improving the yield rate of the product. Moreover, the method is simple to operate, low in cost, and suitable for industrial promotion and use.
[0010] Preferably, the wafer is a silicon wafer, and the etching solution is the hydrofluoric acid solution.
[0011] Preferably, the method further comprises: forming the mask on the silicon wafer, wherein the mask comprises silicon oxide.
[0012] Preferably, the concentration of the hydrofluoric acid solution is 30%-40%, the temperature of the hydrofluoric acid solution is 35-45° C., and the reaction time is 10-30 minutes.
[0013] Preferably, the wafer is a germanium wafer, and the etching solution is the sodium hydroxide solution.
[0014] Preferably, the concentration of the sodium hydroxide solution is 10%-15%, the temperature of the sodium hydroxide solution is 50-60° C., and the reaction time is 15-20 minutes. DETAILED DESCRIPTION
[0015] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with some embodiments. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.
[0016] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.
[0017] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.
[0018] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.
[0019] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.
[0020] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.
[0021] The wet etching separation method of the wafer of the present invention is further described below in conjunction with the embodiments, but the present invention is not limited thereby. The method of the present invention is intended to provide an improved wet etching separation method of the wafer, which is low in cost, simple in operation, and avoids the problems of stress and poor cutting effect caused by mechanical cutting or thermal cutting, thereby reducing the possibility of semiconductor wafer cracking and improving the yield rate of the product.
[0022] In one embodiment of the wet etching separation method of the wafer of the present invention, the following steps are included:
[0023] A mask is formed on the surface of a wafer, and separation marks are formed on the wafer, wherein the mask protects the wafer and exposes the separation marks to the outside;
[0024] forming a photoresist on the mask; and
[0025] The wafer is immersed in an etching solution to separate the wafer along the separation marks, and the etching solution is a hydrofluoric acid solution or a sodium hydroxide solution.
[0026] The present invention adopts a separation method of wet etching, firstly, a mask is formed on the surface of a wafer, a separation notch is formed on the wafer, the mask protects the wafer and exposes the separation notch; then, a photoresist is formed on the mask; the wafer is immersed in an etching solution of a hydrofluoric acid solution or a sodium hydroxide solution to separate the wafer along the separation notch. Compared with traditional mechanical cutting or thermal cutting, the present invention can effectively control the separation edge of the semiconductor wafer, greatly reduce the stress generated by the semiconductor on the semiconductor wafer, reduce the deformation of the semiconductor, thereby reducing the possibility of the semiconductor wafer from cracking, and improving the yield rate of the product. Moreover, the method is simple to operate, low in cost, and suitable for industrial promotion and use.
[0027] Specifically, firstly, the mask of the present invention can protect useful structures on the surface of the wafer to prevent them from being etched, while the separation marks need to be exposed to the outside to directly contact the etching liquid. The present invention can adopt different wet etching methods for wafers of different materials. For example, when using silicon wafers, the etching liquid can be hydrofluoric acid (HF), and when using germanium wafers, the etching liquid can be sodium hydroxide (NaOH), etc.
[0028] As an embodiment, hydrofluoric acid solution (HF) is used as an etching solution to wet etch and separate silicon wafers. Specifically, a thin silicon oxide (SiO2) mask is first formed on the wafer, and a photoresist is formed at the corresponding position of the mask. Then, the wafer is immersed in a 30%-40% HF solution at a temperature of 35-45°C for a reaction time of 10-30 minutes. When the etching is in place, the mask will be completely removed, and the wafer will be separated into independent units along the separation marks, and finally cleaned for use.
[0029] As another embodiment, a sodium hydroxide solution (NaOH) is used as an etching solution to wet etch and separate a germanium wafer. Specifically, a thin mask is first formed on the wafer, and a photoresist is formed at the corresponding position of the mask. Then, the wafer is immersed in a NaOH solution with a concentration of 10%-15%, the temperature of the NaOH solution is 50-60°C, and the reaction time is 15-20 minutes. In the etching solution, the sodium hydroxide solution reacts with germanium to generate germanate ions and water. The etching rate of the germanium wafer depends on the concentration of the germanate ions in the etching solution. When the material of the exposed separation marks on the wafer is etched away, the wafer will be etched into multiple independent units, and finally cleaned and set aside.
[0030] It can be seen that the present invention adopts a separation method of wet etching, and separates the wafer by soaking it in an etching solution of a hydrofluoric acid solution or a sodium hydroxide solution. Compared with traditional mechanical cutting or thermal cutting, the present invention can effectively control the separation edge of the semiconductor wafer, greatly reduce the stress generated by the semiconductor on the semiconductor wafer, reduce the deformation of the semiconductor, thereby reducing the possibility of semiconductor wafer cracking, and improving the yield rate of the product. Moreover, the method is simple to operate, low in cost, and suitable for industrial promotion and use.
[0031] The above disclosure is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention are still within the scope covered by the present invention.
Claims
1. A method for wet etching separation of wafers, characterized in that: The following steps are involved: Forming a mask on the surface of a wafer, forming separation marks on the wafer, wherein the mask protects the wafer and exposes the separation marks to the outside; forming a photoresist on the mask; as well as The wafer is immersed in an etching solution to separate the wafer along the separation marks, and the etching solution is a hydrofluoric acid solution or a sodium hydroxide solution.
2. The wet etching separation method of wafer according to claim 1, characterized in that: The wafer is a silicon wafer, and the etching solution is the hydrofluoric acid solution.
3. The wet etching separation method of wafer according to claim 2, characterized in that: Also includes: The mask is formed on the silicon wafer, and the mask comprises silicon oxide.
4. The wet etching separation method of wafer according to claim 3, characterized in that: The concentration of the hydrofluoric acid solution is 30%-40%, the temperature of the hydrofluoric acid solution is 35-45° C., and the reaction time is 10-30 minutes.
5. The wet etching separation method of wafer according to claim 1, characterized in that: The wafer is a germanium wafer, and the etching solution is the sodium hydroxide solution.
6. The wet etching separation method of wafer according to claim 5, characterized in that: The concentration of the sodium hydroxide solution is 10%-15%, the temperature of the sodium hydroxide solution is 50-60° C., and the reaction time is 15-20 minutes.