JP3157751B2 - Dicing method for semiconductor substrate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of dicing a semiconductor substrate, in which a semiconductor substrate is cut along a dicing line for dividing a chip on which a plurality of semiconductor integrated circuits are formed, the semiconductor substrate is cut and divided into individual chips. .

[0002]

2. Description of the Related Art Conventionally, in this dicing method, a semiconductor substrate (hereinafter, referred to as a wafer) is observed through a monitor camera, and a wafer is placed in a detection range (a region including a part of a wiring pattern in a chip) for determining a dicing line of the wafer. And read the deviation from the position coordinates of the center position of the dicing line from the position coordinates of the center of the detection range,
The measured value of the deviation is stored in the microcomputer,
Then, the position of the dicing line is corrected and the wafer is automatically cut and divided.

[0003] However, according to this method, since the operator inputs the position dimensions, the operator often inputs a numerical value by mistake due to a human error. For this reason,
There has been a problem that a region other than the dicing line is cut.

FIG. 4 is a partially enlarged view of a wafer showing target marks formed in a dicing line. As a method for solving the above-mentioned problem, Japanese Patent Application Laid-Open No. Hei.
No. 6,086,045. In this method, as shown in FIG. 4, a dicing mark 10 is formed at an intersection of a dicing line 7 between chips 8 on a wafer, the dicing mark 10 is detected, and a dicing line passing through the center of the target mark 10 is formed. Automatically recognizes the center line 9 of
The size of each chip is sequentially added to the center line 9 for dicing.

That is, by directly recognizing the dicing mark without reading the distance from the center of the detection range to the center of the dicing line, the blade can be accurately aligned with the dicing line without human error. It is characterized by running and cutting the blade.

[0006]

The above-described method of recognizing and dicing a dicing mark can prevent the intervention of human error, and at the same time, the dicing mark is formed at the same time in the aluminum wiring process and formed at a precise position. Excellent as a mark for use.

However, the reflectivity of the surface of the formed dicing mark is not uniform, the edge is unclear, the position cannot be accurately recognized by the monitor camera, and the blade can be accurately fitted to the dicing line. There is a problem that can not be.

Also, when dicing, there is a problem that chips of aluminum dicing marks are scattered, and minute metal pieces enter between pads in the chip and remain without being removed in a subsequent cleaning step. This remaining metal piece is sealed with resin in a state of being wrapped in the subsequent resin sealing step, causing a short circuit between the pads and causing a failure of the semiconductor device.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method of dicing a semiconductor substrate capable of accurately aligning a blade with a dicing line without forming a dicing mark, cutting the semiconductor substrate, and dividing the semiconductor substrate into chips.

[0010]

A feature of the present invention is that a dicing line for dividing a plurality of chips is vertically and horizontally formed by running a blade along the dicing line of the semiconductor substrate and cutting the semiconductor substrate. In the method of dicing a semiconductor substrate, which cuts and divides each of the chips, a reference semiconductor substrate having the same number and size of the semiconductor substrates and an interval between the chips is prepared, and the reference semiconductor substrate is placed on a stage. The stage is moved in one direction from a fixed position of the stage, the first area including the dicing line of the reference semiconductor substrate is matched with the detection pattern for positioning of the recognition camera, and the matched position coordinates are stored. The reference semiconductor substrate and the semiconductor substrate are replaced from the stage returned to the home position, and then the stage is replaced. Is moved to the stored position coordinates, and it is determined whether or not the detection pattern matches the second area corresponding to the first area of the semiconductor substrate. If the stage is moved and corrected, the position of the center line of the dicing line is obtained from the corrected position coordinates, and the interval of the dicing line is sequentially added to the obtained center line to make the semiconductor substrate stepwise. A method of dicing a semiconductor substrate, wherein the semiconductor substrate is moved in the one direction, and the blade and the stage are moved in a direction perpendicular to the one direction and cut along the dicing line.

It is preferable that the position shift determination and the position shift correction are performed a plurality of times, and when the detected pattern does not match the second area, the subsequent operation is stopped.

[0012]

Next, the present invention will be described with reference to the drawings.

FIGS. 1A and 1B are diagrams showing a detection pattern for explaining a method of dicing a semiconductor substrate according to an embodiment of the present invention, and FIGS. 2A and 2B.
FIG. 1 is a perspective view showing a flow chart for explaining a semiconductor substrate dicing method and an outline of a dicing apparatus according to an embodiment of the present invention. First, a reference wafer having the same outer shape, number of chips, and dicing line width as the wafer to be cut and divided is prepared. In addition, it is desirable that the surface of the chip is coated with an aluminum film so that the edge portion of the chip can be clearly identified, and the surface of the chip is polished so as not to be contaminated.

Further, the monitor camera has a built-in reticle equivalent to the detection pattern shown in FIG. 1 so that a displacement can be recognized. That is, the reticle is drawn as a rectangular frame, and a center line 3 crossing the center of the frame and a reference line 2 corresponding to the edge 4 of the chip 6 are provided.

Next, the dicing method will be described with reference to FIG. Here, the blade 12 and the wafer 1
3 will be described only when it relatively moves in the X direction and cuts. First, in step A of FIG. 2, a reference wafer prepared in advance is placed on a stage at a fixed position.

Next, in step B, as shown in FIG. 1A, the stage 11 is moved from the home position in the Y direction to move the stage 11 to a predetermined area of the reference wafer (for example, including a dicing line closest to the home position). Area) and detection pattern 1 of the monitor camera. Next, in step C, it is determined whether or not the reference line 2 of the detection pattern 1 coincides with the edge 4 of the adjacent chip 6. If they match, the moving distance from the home position is stored in the memory. And the next step E
Move to

If the inclination is deviated, the stage 11
Is rotated and corrected, and if there is further deviation in the Y direction, the stage 11 is moved and corrected in the Y direction as shown in FIG. Then, a correction value obtained by adding the corrected distance to the moving distance from the fixed position is recorded in the memory.
Next, in step E, the dicing line 5 is determined from the moving distance or the corrected moving distance and the width of the dicing line 5.
Is calculated and stored in the memory.
Then, the stage 11 returns to the home position. This completes the preparation work.

Next, in step F, the reference wafer is removed, and the wafer 13 to be cut is placed on the stage 11. Then, in step G, the stage 11 moves by the distance stored in the memory. In step H, the monitor camera automatically recognizes whether or not the detection pattern 1 matches the predetermined area range of the wafer 13. If they match, proceed to the next step.

If they do not coincide with each other as shown in FIG. 1A, the tilt is detected by the monitor camera and the stage 11 is rotated in step I to rotate the stage 11 so that the center line of the dicing line 5 and the center line 3 of the detection pattern 1 are detected. After correcting the inclination, the deviation in the Y direction due to the inclination is corrected by moving the stage, and the correction value is stored in a memory in addition to the distance to be moved. Next, the stage 11 is returned to the original home position, and dicing is started in step J. To do this, rotate the blade 12 and move the stage 1 from the home position by the distance set in the memory.
Then, the stage is moved in the X direction to cut the first dicing line 5. Then, each time the stage 11 changes direction, the stage 11 is stepped by one pitch in the Y direction to cut the dicing line 5 sequentially.

FIG. 3 is a flowchart for explaining a method of dicing a semiconductor substrate according to another embodiment of the present invention. In the dicing method described above, the edge 4 of the chip 6 in FIG. 1 is clear under the condition that recognition is performed smoothly. However, the contrast is not always obtained so that the edges 4 of all the chips 6 can be recognized, and the edge 4 may be unclear.

In such a case, even if the monitor camera recognizes and corrects it, accurate positioning cannot be expected. Also,
Unless the wafer is accurately positioned, the wafer will cause chips to be damaged, resulting in poor yield. Therefore, in the present embodiment, this problem is solved.

This dicing method corresponds to step G in FIG.
The steps up to this point are the same as those of the above-described embodiment, and thus are omitted.
First, in step H, it is determined whether there is any displacement. Here, if there is no displacement, as described above, step J
To start dicing. If there is a displacement, the displacement is corrected in step I. Then, in step K, the number of corrections is counted, and in step H, it is checked whether there is any displacement.

In step H, if there is still a displacement, the displacement is corrected in step I, and the number of corrections is counted in step K.

As described above, when the number of corrections exceeds the number in step L, it is determined that the edge 4 of the chip 6 is unclear and cannot be recognized by the monitor camera.
Stop the operation at the same time as generating the alarm.

In such a case, the next predetermined area (for example, the area of the dicing line which is second closest to the fixed position)
Alternatively, the processing may be performed from step A by aligning the detection pattern with a region where a clear contrast can be obtained.

Although the detection pattern has been described as a strip-shaped pattern including two chips and straddling a dicing line, the present invention is not limited to this shape.

[0027]

As described above, according to the present invention, the detection pattern for positioning is built in the monitor camera, a reference wafer having the same number of chips as the wafer to be cut is prepared, and the reference wafer is previously set on the stage. The mounted detection pattern is aligned with the dicing line of the reference wafer, corrected as necessary, and the set position coordinates are stored. The wafer to be cut mounted on the stage is replaced with the position coordinates instead of the reference wafer. By moving the blade to the dicing line, the blade can be accurately aligned with the dicing line even if no identification mark is formed in the dicing line of the wafer, and the yield can be reduced without causing chip contamination or chip loss that may cause a short circuit of the pad. There is an effect that the improvement can be achieved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a detection pattern for describing a dicing method of a semiconductor substrate according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a flow chart for explaining a method of dicing a semiconductor substrate and an outline of a dicing apparatus according to an embodiment of the present invention;

FIG. 3 is a flowchart illustrating a method of dicing a semiconductor substrate according to another embodiment of the present invention.

FIG. 4 is a partially enlarged view of the wafer showing a target mark formed in a dicing line.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Detection pattern 2 Reference line 3 Center line 4 Edge 5, 7 Dicing line 6, 8 Chip 9 Center line 10 Dicing mark 11 Stage 12 Blade 13 Wafer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/301 B28D 5/02 H01L 21/02

Claims (2)

(57) [Claims] 1. A semiconductor substrate for cutting and dividing each of said chips from said semiconductor substrate by running a blade along said dicing line of said semiconductor substrate on which dicing lines for partitioning a plurality of chips are formed vertically and horizontally. In the dicing method, a reference semiconductor substrate having the same number of chips, the same size, and the same interval between the chips of the semiconductor substrate is prepared, the reference semiconductor substrate is placed on a stage, and the stage is moved from a fixed position of the stage to one stage. The first area including the dicing line of the reference semiconductor substrate is moved in the direction and the detection pattern for positioning of the recognition camera is made to coincide with the first area, and the position coordinates are stored, and from the stage returned to the home position, The reference semiconductor substrate is replaced with the semiconductor substrate, and then the stage is stored at the stored position coordinates. Move, determine whether or not the detection pattern coincides with the second area corresponding to the first area of the semiconductor substrate, and if there is a positional shift, move and correct the stage; Determine the position of the center line of the dicing line from the corrected position coordinates,
The semiconductor substrate is moved stepwise in the one direction by sequentially adding the dicing line interval to the obtained center line, and the blade and the stage are moved in a direction perpendicular to one direction to cut at the dicing line. A method for dicing a semiconductor substrate, comprising: 2. The apparatus according to claim 1, wherein the position shift determination and the position shift correction are performed a plurality of times, and when the detected pattern does not match the second area, the subsequent operation is stopped. Dicing method for semiconductor substrate.