CN110587835A - A kind of cutting method of grating silicon wafer - Google Patents

Abstract

The invention discloses a method for cutting a grating silicon wafer, comprising: providing a circular grating silicon wafer, and determining the coordinates of four points evenly distributed along the circumference on the edge position of the surface of the grating silicon wafer; Four marks corresponding to the coordinates of the points are formed on the edge positions of the surface of the grating silicon wafer; the positions of the four marks on the grating silicon wafer are detected by using the visual image positioning function on the dicing machine; The connection between the marks defines a square cutting area on the grating silicon wafer; according to the cutting area, the cutting starting point and the cutting path stroke are determined; using the dicing machine, the grating silicon is An effective grating corresponding to the area of the cut area is cut out on the chip. The invention can realize cutting out the maximum effective grating area of the grating silicon wafer simply, accurately and efficiently.

Description

A kind of cutting method of grating silicon wafer

technical field

The invention relates to the technical field of integrated circuit manufacturing, in particular to a precision cutting method capable of cutting a plane grating silicon wafer to obtain the largest effective grating.

Background technique

When using semiconductor cutting equipment (such as a dicing machine) to cut a grating silicon wafer (wafer), it is easy to destroy many effective gratings during cutting because the starting point of cutting cannot be accurately positioned and the effective grating with the largest area cannot be drawn. , the actual cutting area shown by the rectangular box in Figure 1. This reduces the grating utilization.

In the current field of semiconductor cutting, when cutting a planar grating silicon wafer, only wafer alignment is performed through an alignment mark on the silicon wafer, and each chip in the silicon wafer is cut out. However, there is no good positioning solution for the effective grating pattern to be cut out with the largest area; and the existing cutting method, due to the lack of travel limit marks, will destroy many effective gratings during the cutting process. Therefore, problems such as large cutting error and low utilization rate of effective area have always existed.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the above-mentioned defects in the prior art, and to provide a method for cutting a grating silicon wafer, so as to simply and efficiently cut out the maximum effective grating area of the grating silicon wafer.

For achieving the above object, technical scheme of the present invention is as follows:

A method for cutting a grating silicon wafer, comprising:

A circular grating silicon wafer is provided, and coordinates of four points evenly distributed along the circumference are determined on the edge position of the surface of the grating silicon wafer;

forming four marks corresponding to the coordinates of the point on the edge position of the surface of the grating silicon wafer;

Using the visual image positioning function on the dicing machine, the positions of the four marks on the grating silicon wafer are detected; according to the connection between the four marks, a square cut is determined on the grating silicon wafer area; according to the cutting area, determine the starting point of cutting and the stroke of the cutting path;

Using the dicing machine, an effective grating corresponding to the area of the cut area is cut out on the grating silicon wafer.

Further, determining the coordinates of four uniformly distributed points on the edge positions of the surface of the grating silicon wafer specifically includes:

Taking the center of the grating silicon wafer as the coordinate origin, a rectangular coordinate system is established on the grating silicon wafer;

The coordinates of the four points that are equidistant from the coordinate origin are determined on the X-axis and the Y-axis of the rectangular coordinate system, and the coordinates of the points are located at the edge of the grating silicon wafer surface and the X-axis where it intersects the Y axis.

Further, forming four marks corresponding to the coordinates of the point on the edge position of the surface of the grating silicon wafer specifically includes:

Using a photomask, according to the coordinates of the points, four exposure marks corresponding to the coordinates of the points are formed on the edge positions of the surface of the grating silicon wafer.

Further, the exposure marks are cross-shaped, and the connecting lines connect intersections of the cross-shaped marks.

Further, one side of the cross shape of every two adjacent exposure marks is aligned.

Further, the dicing machine establishes the connection line according to one side aligned in the cross shape of every two adjacent exposure marks.

Further, the dicing machine establishes cutting coordinates in the horizontal and vertical directions in the coordinate system of the dicing machine according to the corresponding sides in the crosses of each two adjacent exposure marks.

Further, it is determined that one of the four marks is used as the cutting start point and the cutting end point.

Further, the cutting path stroke is determined by the cutting starting point and the cutting end point and the four connecting lines connecting the marks in sequence between the cutting starting point and the cutting end point.

Further, according to the cutting path, an effective grating with the largest area is drawn.

The present invention has the following remarkable features:

(1) In the form of special marking on the grating silicon wafer, through the visual image positioning system of the dicing machine, the dicing position can be directly detected, and the effective grating with the largest area can be accurately marked, which is simple and efficient to realize.

(2) Compared with the conventional cutting technology in which only two alignment marks are used for wafer alignment, and the center position of the chip needs to be marked for positioning, the present invention exposes four marks through an exposure machine. The accuracy can reach within 1 micron, and the starting point and path stroke of the scribing can be determined.

Description of drawings

FIG. 1 is a schematic diagram of an existing grating cutting method.

2-6 are schematic diagrams of application of a method for cutting a grating silicon wafer according to a preferred embodiment of the present invention.

Detailed ways

The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

It should be noted that, in the following specific embodiments, when describing the embodiments of the present invention in detail, in order to clearly represent the structure of the present invention for the convenience of description, the structure in the accompanying drawings is not drawn according to the general scale, and the Partial enlargement, deformation and simplification of processing are shown, therefore, it should be avoided to interpret this as a limitation of the present invention.

In the following specific embodiments of the present invention, please refer to FIGS. 2-6 , which are schematic diagrams of application of a method for cutting a grating silicon wafer according to a preferred embodiment of the present invention. As shown in FIG. 2-FIG. 6, a method for cutting a grating silicon wafer of the present invention includes:

In the first step, a circular grating silicon wafer is provided, and a grating pattern is fabricated on the grating silicon wafer. The coordinates of four points evenly distributed along the circumference are determined on the edge positions of the grating silicon wafer surface.

The grating silicon wafer can be put into the exposure machine, and a rectangular coordinate system can be established on the grating silicon wafer with the center of the grating silicon wafer as the coordinate origin using the positioning system that comes with the exposure machine. The present invention is not limited to this. Then, the coordinates of four points equidistant from the coordinate origin are determined on the X-axis and the Y-axis of the Cartesian coordinate system. The coordinates of the four points are located where the edge of the grating silicon surface intersects the X and Y axes.

For example, as shown in Fig. 2, the Y direction in the rectangular coordinate system can be determined on the grating silicon wafer first, and the vertical direction passing through the center of the grating silicon wafer can be drawn along the bottom-up vertical direction of the grating silicon wafer shown in the figure. Line Y (Y-axis).

Next, as shown in Fig. 3, the X direction in the rectangular coordinate system is determined on the grating silicon wafer, and along the horizontal direction from left to right of the grating silicon wafer shown in the figure, the center of the circle (center point) of the grating silicon wafer is drawn. Horizontal line X (X axis).

Then, the four points where the horizontal line X and the vertical line Y intersect with the edge of the surface of the grating silicon wafer are used as the point coordinates for subsequent marking, that is, the coordinates of the points are located on the X axis and the Y axis position, and the four points The coordinates are on the same circumference.

The position of the coordinates of the point on the edge of the grating silicon wafer can be determined on the grating silicon wafer by using the imaging system of the exposure machine.

Connect the horizontal line X (X axis) and the vertical line Y (Y axis) to the four points where the edge of the grating silicon chip intersects, and a square with the largest area surrounded by four connecting lines is obtained, as shown in the square line in Figure 4 box shown. This square is the subsequently determined grating cut area.

In the second step, four marks corresponding to the coordinates of the points are formed on the edge positions of the surface of the grating silicon wafer.

For example, according to the coordinates of the formed dots, input the coordinates of the dots into the exposure machine, and use a mask to expose four exposure marks corresponding to the coordinates of the dots on the edge position of the surface of the grating silicon wafer.

As a preferred embodiment, the exposure mark can be in the shape of a cross, and the intersection of the cross-shaped mark corresponds to the coordinates of the point. That is, when connecting the lines, the intersection of the cross-shaped mark is used as the connection point. Using the exposure technique, the precision of the formed four exposure marks can be within 1 micron.

In order to facilitate the horizontal and vertical drawing of the dicing machine, when making exposure marks, one side of the cross shape of every two adjacent exposure marks can be aligned, that is, located on the same straight line. The four corners of the square (the dotted frame shown in the figure) are the positions of the four exposure marks mark1 to mark4 , and the exposure marks mark1 to mark4 have a cross shape, as shown in FIG. 5 .

The third step is to input the grating silicon wafer with the exposure marks into the dicing machine, and use the visual image positioning system that comes with the dicing machine to directly detect the positions of the four exposure marks on the grating silicon wafer, and accurately mark the largest area of the silicon wafer. Effective grating, simple and efficient to implement.

In the fourth step, a square cutting area is determined on the grating silicon wafer according to the connection between the four exposure marks. The dicing machine establishes a connection line according to one edge aligned in the cross shape of every two adjacent exposure marks. The 4 corners of the square are the positions of the 4 exposure marks, as shown in Figure 5.

The fifth step is to further determine the starting point of cutting and the stroke of the cutting path according to the determined cutting area.

One of the four exposure marks is used as the cutting start point and the cutting end point at the same time, and the four connecting lines connecting each mark in turn between the cutting start point and the cutting end point are used to determine the cutting path stroke. For example, according to the connection line of mark1→mark2→mark3→mark4→mark1 shown in FIG. 6 , the cutting path stroke is determined.

The dicing machine establishes cutting coordinates in the horizontal and vertical directions in the coordinate system of the dicing machine according to the corresponding sides in the cross shape of every two adjacent exposure marks.

In the sixth step, a dicing machine is used to cut an effective grating corresponding to the area of the cut area on the grating silicon wafer.

That is, according to the mark1→mark2→mark3→mark4→mark1 cutting path shown in FIG. 6 , the effective grating with the largest area is drawn.

The above are only the preferred embodiments of the present invention, and the embodiments are not intended to limit the protection scope of the present invention. Therefore, any equivalent structural changes made by using the contents of the description and drawings of the present invention shall be included in the protection of the present invention. within the range.

Claims (10)

1. a method for cutting a grating silicon wafer, comprising: A circular grating silicon wafer is provided, and coordinates of four points evenly distributed along the circumference are determined on the edge position of the surface of the grating silicon wafer; forming four marks corresponding to the coordinates of the point on the edge position of the surface of the grating silicon wafer; Using the visual image positioning function on the dicing machine, the positions of the four marks on the grating silicon wafer are detected; according to the connection between the four marks, a square cut is determined on the grating silicon wafer area; according to the cutting area, determine the starting point of cutting and the stroke of the cutting path; Using the dicing machine, an effective grating corresponding to the area of the cut area is cut out on the grating silicon wafer. 2 . The method for cutting a grating silicon wafer according to claim 1 , wherein the coordinates of four uniformly distributed points are determined on the edge positions of the surface of the grating silicon wafer, and the method specifically includes: 3 . Taking the center of the grating silicon wafer as the coordinate origin, a rectangular coordinate system is established on the grating silicon wafer; The coordinates of the four points that are equidistant from the coordinate origin are determined on the X-axis and the Y-axis of the rectangular coordinate system, and the coordinates of the points are located at the edge of the grating silicon wafer surface and the X-axis where it intersects the Y axis. 3 . The method for cutting a grating silicon wafer according to claim 1 , wherein the forming four marks corresponding to the coordinates of the points on the edge position of the surface of the grating silicon wafer, specifically comprising: 4 . : Using a photomask, according to the coordinates of the points, four exposure marks corresponding to the coordinates of the points are formed on the edge positions of the surface of the grating silicon wafer. 4 . The method for cutting a grating silicon wafer according to claim 3 , wherein the exposure marks are cross-shaped, and the connecting lines connect intersections of the cross-shaped marks. 5 . 5 . The method for cutting a grating silicon wafer according to claim 4 , wherein one side of the cross shape of every two adjacent exposure marks is aligned. 6 . 6 . The method for cutting a grating silicon wafer according to claim 5 , wherein the dicing machine establishes the connection according to one edge aligned in the cross shape of every two adjacent exposure marks. 7 . Wire. 7 . The method for cutting a grating silicon wafer according to claim 5 , wherein the dicing machine cuts the dicing machine on the dicing machine according to the corresponding sides in the cross shape of every two adjacent exposure marks. 8 . The cutting coordinates in the horizontal and vertical directions are established in the coordinate system of . 8. The method for cutting a grating silicon wafer according to claim 1 or 4, wherein one of the four marks is determined as the cutting start point and the cutting end point. 9 . The method for cutting a grating silicon wafer according to claim 8 , wherein the cutting path is determined by the cutting starting point and the cutting end point and the four connecting lines connecting the marks in sequence therebetween. 10 . journey. 10 . The method for cutting a grating silicon wafer according to claim 9 , wherein the effective grating with the largest area is drawn according to the cutting path. 11 .