CN110729239A

CN110729239A - Wafer cutting method

Info

Publication number: CN110729239A
Application number: CN201910706706.2A
Authority: CN
Inventors: 刘欢
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-08-01
Filing date: 2019-08-01
Publication date: 2020-01-24

Abstract

The invention discloses a wafer cutting method, which belongs to the technical field of semiconductor wafer cutting and comprises the following steps: s1, cutting the front side of a wafer to form a plurality of transverse cutting grooves and a plurality of longitudinal cutting grooves which do not penetrate through the wafer; s2, cutting the wafer along two different transverse cutting grooves by using two blades respectively, and cutting off the wafer; s3, cutting the wafer along two different longitudinal cutting grooves by using the two blades respectively, and cutting off the wafer; steps S2 and S3 are not in order. The cutting of the wafer surface and the cutting of the silicon layer are respectively carried out, and the two blades are used for cutting off simultaneously, so that the wafer cutting speed is greatly improved, the wafer cutting period is shortened, and the efficiency is greatly improved compared with the traditional cutting mode. Under the condition of cutting the same number of wafers, the number of required machines is reduced, and the production cost is greatly saved.

Description

Wafer cutting method

Technical Field

The invention belongs to the technical field of semiconductor wafer cutting, and particularly relates to a wafer cutting method.

Background

Currently, semiconductor wafers are diced by a dicing saw, which is equipped with two spindles, each of which can be mounted with a cutting blade, respectively a knife one and a knife two. The cutting process mainly comprises two types, wherein the first type is a step-by-step cutting method: the first cutter and the second cutter are different in model, the first cutter is thicker than the second cutter, after the two blades are arranged in front of each other, the first cutter cuts into a part of the front surface of the wafer but does not cut through, the front surface of the wafer is the surface for manufacturing a circuit element on the wafer, and then the second cutter cuts into the wafer from the cutting mark of the first cutter to cut through the silicon layer at the bottom of the wafer, as shown in figure 1; the second is a synchronous cutting method: the first cutter and the second cutter have the same model, and the two cutters simultaneously cut the wafer and completely cut the wafer at one time.

The first process is the most popular process in the wafer cutting industry, and has high cutting quality but a slow speed, because the cutting action is advanced by a worktable adsorbing the wafer, that is, the cutting speeds of the first knife and the second knife must be consistent, and in the actual cutting process, because the material on the surface of the wafer is more complex, the cutting speed of the first knife is required to be slow to ensure the cutting quality, so the speed of the second knife is limited. In addition, a certain safety distance must be reserved between the first knife and the second knife to avoid collision, so that the two knives have the time of waiting for each other when working. The second process is only applied to the cutting of a wafer with a single material, the cutting speed is higher than that of the first process, but the second process causes the load of the blade to be large, and quality defects of chip chipping are easily caused.

Disclosure of Invention

The invention aims to provide a wafer cutting method, which can improve the wafer cutting speed and improve the production efficiency. So as to solve the problem of low efficiency of the first process of the current mainstream.

In order to realize the purpose of the invention, the technical scheme is as follows: a wafer cutting method comprises the following steps:

s1, cutting the front side of a wafer to form a plurality of transverse cutting grooves and a plurality of longitudinal cutting grooves which do not penetrate through the wafer;

s2, cutting the wafer along two different transverse cutting grooves by using two blades respectively, and cutting off the wafer;

s3, cutting the wafer along two different longitudinal cutting grooves by using the two blades respectively, and cutting off the wafer; steps S2 and S3 are not in order.

As a further alternative, in step S1, laser cutting or knife cutting is used.

As a further alternative, when the cutter is used for cutting in step S1, the method further includes the following steps:

s11, respectively and transversely cutting the front surface of the wafer at two different positions by using a first blade and a second blade to form the transverse cutting groove;

s12, respectively and longitudinally cutting the front surface of the wafer to form a longitudinal cutting groove at two different positions by using the first blade and the second blade; steps S11 and S12 are not in order.

As a further alternative, the cutting start of the first and second blades in step S11 may be the same as or different from the cutting start of the first and second blades in step S12.

In steps S11 and/or S12, the first blade and the second blade respectively perform a transverse cutting or a longitudinal cutting with the two sides of the wafer as the cutting start points, and step toward the inside of the wafer to form a plurality of transverse cutting grooves or longitudinal cutting grooves.

As a further alternative, the two blades in steps S2 and S3 are a third blade and a fourth blade, and the cutting speed of the third blade and the fourth blade is greater than the cutting speed of the first blade and the second blade.

As a further alternative, the wafer is rotated between steps S11 and S12.

As a further alternative, the steps S1-S3 may be performed on one cutting apparatus, or on two cutting apparatuses.

As a further alternative, when steps S1-S3 are performed on one cutting apparatus, the cutting tool required for cutting in step S1 and the two blades in steps S2 and S3 are provided on one cutting apparatus and are individually drive-controlled.

As a further alternative, when steps S1-S3 are performed on two cutting implements, step S1 is performed on the first cutting implement and then steps S2 and S3 are performed on the second cutting implement.

As a further alternative, the cutting start of the two blades in step S2 may be the same or different from the cutting start of the two blades in step S3.

In steps S2 and/or S3, the two blades respectively start cutting with the transverse cutting groove or the longitudinal cutting groove near the edge of the two sides of the wafer, and step-cut towards the inside of the wafer.

The invention has the beneficial effects that: through at first cutting the wafer openly once, form a plurality of vertically and horizontally staggered's cutting groove, use two blades to cut the remaining silicon layer simultaneously from the cutting groove of different positions fast after the cutting is accomplished, be about to the wafer cut through, carry out the cutting on wafer surface and to the cutting of silicon layer respectively to cut off simultaneously through two blades, promoted wafer cutting's speed by a wide margin, shortened wafer cutting's cycle, compare efficiency with traditional cutting mode and have very big promotion. Under the condition of cutting the same number of wafers, the number of required machines is reduced, and the production cost is greatly saved.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, it should be understood that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic diagram of a prior art cutting process;

fig. 2 is a schematic diagram illustrating a principle of cutting by a blade in step S1 of the wafer cutting method according to the embodiment of the present invention;

FIG. 3 is a schematic diagram illustrating the dicing in steps S2 and S3 according to the wafer dicing method of the present invention;

reference numerals: 1. a first blade; 2. a second blade; 3. a third blade; 4. and a fourth blade.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without any inventive step, are within the scope of the present invention. It is to be understood that the drawings are provided solely for the purposes of reference and illustration and are not intended as a definition of the limits of the invention. The connection relationships shown in the drawings are for clarity of description only and do not limit the manner of connection.

It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

The invention is further described with reference to the following figures and specific embodiments.

The wafer cutting method provided by the embodiment of the invention comprises the following steps:

The plurality of transverse cutting grooves and the plurality of longitudinal cutting grooves are perpendicular to each other and crisscross. The two-blade cutting start in step S2 may be the same as or different from the two-blade cutting start in step S3.

The cutting start of the two blades in step S2 is the same as or different from the cutting start of the two blades in step S3.

In steps S2 and/or S3, the two blades respectively start cutting with the transverse cutting groove or the longitudinal cutting groove near the edge of the two sides of the wafer, and step-cut towards the inside of the wafer. In other words, in both steps S2 and S3, the two blades respectively use the transverse cutting groove or the longitudinal cutting groove at the edge near the two sides of the wafer as the cutting start point, and cut the wafer step by step towards the inside of the wafer; or one of the steps S2 and S3, the two blades respectively start cutting with the transverse cutting groove or the longitudinal cutting groove near the edge of the two sides of the wafer, and cut step by step towards the inside of the wafer. And the step is performed towards the inside of the wafer, namely, the step is performed towards the central area of the wafer so as to complete a plurality of transverse/longitudinal cutting grooves in sequence, the step directions are opposite, the efficiency is high, and the realization equipment is simple. Other locations may be used as the beginning of the cut, so long as the two blades cut simultaneously along two different transverse/longitudinal cutting grooves. The cutting start position and the stepping direction can be adjusted according to the process requirements.

Between steps S2 and S3, the wafer is rotated by a corresponding angle, such as 90 °, according to the actual shape of the chip, so as to change the longitudinal direction and the transverse direction, or two blades are rotated and moved. The two blades are respectively a third blade 3 and a fourth blade 4, and the cutting speeds of the two blades are the same.

In step S1, laser cutting or knife cutting may be utilized. Laser cutting can be achieved by existing laser cutting tools. When the cutter is used for cutting, the method also comprises the following steps:

s11, respectively and transversely cutting the front surface of the wafer to form the transverse cutting groove at two different positions by using the first blade 1 and the second blade 2;

s12, respectively cutting the front surface of the wafer at two different positions by using the first blade 1 and the second blade 2 to form a longitudinal cutting groove; steps S11 and S12 are not in order.

Thus, when the front surface of the wafer is partially cut, the wafer is simultaneously cut by the first blade 1 and the second blade 2, see fig. 2, and then the wafer is completely cut by the third blade 3 and the fourth blade 4, see fig. 3, so that the wafer is separated into independent chips, four blades are totally adopted for cutting the wafer, the cutting speed of the prior art can be kept when the first blade 1 and the second blade 2 cut the front surface of the wafer, good cutting quality is ensured, the speed can be increased when the third blade 3 and the fourth blade 4 cut the silicon layer at the bottom of the wafer, the speed is higher than that of the step S1, and particularly, the speed can be increased to 2-3 times or even higher than that of the step S1. The speed of wafer cutting is greatly improved, the cycle of the wafer cutting process is shortened, and time waste caused by mutual waiting of blades is avoided.

The cutting start of the first blade and the second blade in step S11 is the same as or different from the cutting start of the first blade and the second blade in step S12.

In steps S11 and/or S12, the first blade 1 and the second blade 2 respectively perform a transverse cutting or a longitudinal cutting with the two sides of the wafer as the cutting start points, and step toward the inside of the wafer to form a plurality of transverse cutting grooves or longitudinal cutting grooves. That is, in both steps S11 and S12, the first blade 1 and the second blade 2 respectively cut transversely or longitudinally with the two sides of the wafer as the cutting start points, and step toward the inside of the wafer; or one of the steps S2 and S3 is to cut the wafer laterally or longitudinally with the first blade 1 and the second blade 2 as the starting points of the cut, respectively, on both sides of the wafer, and step toward the inside of the wafer. The cutting starting position and the stepping direction of the first blade and the second blade can be adjusted according to the process requirements.

Between the steps S11 and S12, the wafer is rotated by a corresponding angle, such as 90 °, according to the actual shape of the chip, so as to change the longitudinal and transverse directions, or the first blade 1 and the second blade 2 are rotated, moved, and the like.

The steps S1-S3 may be performed on one cutting apparatus, or on two cutting apparatuses. The method is realized through different equipment forming modes, the cutting tool required by each step can be installed on one piece of equipment by using one piece of cutting equipment, the step can be split into two pieces of equipment by using two pieces of cutting equipment, and the two pieces of equipment can adopt the existing wafer cutting equipment.

When steps S1 to S3 are performed on one cutting apparatus, the cutting tool required for cutting in step S1 and the two blades in steps S2 and S3 are each provided on one cutting apparatus, and are individually drive-controlled. The cutting tool required for cutting in step S1 may be a laser cutting tool or a cutter, or the like. When steps S1-S3 are performed on two cutting apparatuses, step S1 is performed on the first cutting apparatus, and then steps S2 and S3 are performed on the second cutting apparatus.

The invention is not limited to the above alternative embodiments, and any other various forms of products can be obtained by anyone in the light of the present invention, but any changes in shape or structure thereof, which fall within the scope of the present invention as defined in the claims, fall within the scope of the present invention.

Claims

1. A wafer cutting method is characterized by comprising the following steps:

2. The wafer dicing method according to claim 1, wherein in step S1, the wafer is diced by laser or knife.

3. The wafer dicing method according to claim 2, wherein the dicing with the cutter in step S1 further includes:

4. The wafer dicing method according to claim 3, wherein the dicing start locations of the first blade and the second blade in the step S11 are the same as or different from the dicing start locations of the first blade and the second blade in the step S12.

5. The wafer cutting method as claimed in claim 3, wherein the two blades in steps S2 and S3 are a third blade and a fourth blade, and the cutting speed of the third blade and the fourth blade is greater than that of the first blade and the second blade.

6. The wafer dicing method of claim 3, wherein between steps S11 and S12, the wafer is rotated.

7. The wafer dicing method according to claim 1, 3 or 5, wherein the steps S1-S3 are performed on one dicing apparatus or on two dicing apparatuses.

8. The wafer dicing method according to claim 7, wherein when the steps S1-S3 are performed on one dicing apparatus, the dicing tool required for the dicing in the step S1 and the two blades in the steps S2 and S3 are provided on one dicing apparatus and are individually drive-controlled.

9. The wafer dicing method according to claim 7, wherein the steps S1-S3 are performed on two dicing apparatuses, and the step S1 is performed on a first dicing apparatus, and then the steps S2 and S3 are performed on a second dicing apparatus.

10. The method as claimed in claim 1, wherein the cutting start of the two blades in step S2 is the same as or different from the cutting start of the two blades in step S3.