JPH03177049A - Scribing method and device for semiconductor wafer - Google Patents

Abstract

PURPOSE:To properly maintain the height amount from the lower surface of an adhesive tape to the lower surface of a scribing blade by arranging a light source and a light receiver under the rear surface of a semiconductor wafer to monitor the lower surface of the semiconductor wafer and the lower surface of a cutting blade. CONSTITUTION:A semiconductor wafer 3 is applied to a base film 1 by an adhesive material layer 2, and the base film 1 is held on a wafer chuck 5 by the negative pressure of a vacuum chuck provided on the wafer chuck 5. Light 11 is emitted from a light source 6 such as a laser and is converged by a lens, etc., to irradiate the lower surface of the wafer 3. The reflected light 12 thereof is received by a light receiver 7. The wafer 3 prepared in this manner is scribed by a blade 9. The lower surface of the blade 9 coming out of the wafer 3 by passing therethrough is irradiated with the light beam 11 from the light source 6, and the reflected light 12 therefrom is received by the light receiver 7 to monitor the height of the lower surface of the blade 9. Thus, the height amount H can be calculated from the height of the lower surface of the wafer 3 measured beforehand and the thicknesses of the base film 1 and the adhesive material layer 2.

Description

[Detailed Description of the Invention] [Summary] Regarding a method and apparatus for scribing a semiconductor wafer into semiconductor chips, the present invention relates to a method and an apparatus for scribing a semiconductor wafer into a semiconductor chip, and an object of the present invention is to maintain an appropriate height from the bottom surface of an adhesive tape supporting the semiconductor wafer to the bottom surface of a scribing blade. The present invention aims to provide a method for scribing a semiconductor wafer into a semiconductor chip, in which the semiconductor wafer is placed on a wafer chuck having a transparent part and supported on a base film having an adhesive layer. A process of arranging a wafer, a process of monitoring the height of the bottom surface of the semiconductor wafer supported on the base film, and a process of monitoring the height of the edge of the semiconductor wafer when the semiconductor wafer is scribed with the scribing blade. and a step of controlling the height from the lower surface of the base film to the blade end using the monitored height of the blade end.

[Industrial Application Field] The present invention relates to wafer scribing in the manufacturing process of semiconductor devices, and particularly to a method and apparatus for scribing a semiconductor wafer into a semiconductor chip.

After fabricating a large number of semiconductor circuits on a semiconductor wafer,
A semiconductor wafer is scribed into a large number of semiconductor chips. In the scribing process, a semiconductor wafer is pasted onto an adhesive tape and cut from above. At this time, it is desirable to control the height from the bottom surface of the adhesive tape to the bottom surface of the scribing blade, that is, the height amount.

[Prior art] In a conventional wafer scribing process, a pilot wafer is attached to an adhesive tape, the scribing process is performed, the height l is measured, and the desired amount of bite is obtained based on the measurement data. It controlled the height for scribing. However, due to wear of the blade of the scribing device and variations in the thickness of the wafer adhesive tape, variations in the amount of bites occur when processing a large number of wafers.

[Problems to be Solved by the Invention] According to the conventional techniques described above, variations in height occur in the scribing process of semiconductor wafers. If the height is too large, the blade will not reach the bottom surface of the semiconductor wafer and the scribing process will not be completed, resulting in failure to separate the semiconductor chips or chipping of the semiconductor chips. If the height is too small, the blade will penetrate too deeply into the tape and the adhesive material will adhere to the sides of the semiconductor chip. After the scribing process, there is a DDB process in which each semiconductor chip is pushed up from below, sucked up by a chuck or collet, and die-bonded onto the lead frame, but adhesive materials may adhere to the sides of the semi-grooved chip/tub. If the adhesive strength is too strong, it will cause suction failure.Although it is possible to reduce the adhesive strength with UV light, etc., it cannot be fixed if there is variation.Also, in some cases, the blade may directly damage the wafer chuck. It can happen.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for scribing a semiconductor wafer, which can maintain an appropriate amount of bite from the lower surface of an adhesive tape supporting the semiconductor wafer to the lower surface of a scribing blade.

Another object of the present invention is to provide a scribing apparatus that can carry out the above-described semiconductor wafer scribing method.

[Means for Solving the Problems] In order to solve the above problems, the scribing blade Detect the height of.

By measuring the interface between the adhesive tape and the semiconductor wafer in advance, it is possible to monitor how far the lower surface of the blade has reached.

Since the bite amount can be monitored and controlled during the scribing process, the height amount can be stably controlled to a desired value.

Therefore, it is possible to prevent inconveniences caused by uneven cutting depth of the blade due to variations in height. A window 4 made of a transparent material is disposed in a part of the window 5, and a light measurement device including a laser light source 6 and a light receiver 7 is disposed below the window 4. , a base film 1 made of polyolefin or the like, an adhesive layer 2 formed on the base film 1, and an adhesive layer 2.
A semiconductor wafer 3 adhesively supported is placed. That is, the semiconductor wafer 3 is stuck to the base film 1 by the layer 2 of adhesive material, and the base film 1 is held on the wafer chuck 5 by the negative pressure of a vacuum chuck suitably provided on the wafer chuck 5. Light 11 is emitted from light a6 of a laser or the like, is focused by a lens or the like as necessary, and illuminates the lower surface of the semiconductor wafer 3. Reflected light 12 from the lower surface of the semiconductor wafer 3 is collected by a lens or the like and received by a light receiver 7.

For example, while irradiating the lower surface of the semiconductor wafer 3 with collimated laser light, the light receiver 7 equipped with a fixed focus lens
When scanning in the height direction, the maximum light intensity is obtained at a height that satisfies a predetermined imaging relationship. By measuring this height, the height of the lower surface of the semiconductor wafer 3 can be measured. Furthermore, if the parallelism between the lower surface of the base film 1 and the lower surface of the semiconductor wafer 3 is ensured, interference of reflected light from both surfaces can also be utilized. Note that height measurement using light is not limited to these methods.

As shown in FIG. 3(B), the semiconductor wafer 3 thus prepared is scribed with a blade 9. In the scribing process, the scribing blade 9 grinds the semiconductor wafer 3 and reaches the lower adhesive layer 2 and the upper layer of the base film 1. The light ray 1 from the light a6 illuminates the lower surface of the blade 9 that penetrates through this semiconductor wafer 3 and comes out.
1 and monitor. That is, the light beam 11 is reflected by the lower surface of the blade 9, and the light 12 is received by the light receiver 7, and the height of the lower surface of the blade 9 is monitored. As a result, the height i is determined from the height of the lower surface of the semiconductor wafer 3 and the thickness of the base film 1 and the adhesive layer 2, which have been measured in advance.
H can be calculated.

For example, a semiconductor wafer scribing blade has a width of about 60 μm and a height of about 1.2111 mm, the semiconductor wafer 3 has a thickness of about 490 μm, the adhesive layer 2 has a thickness of 20 μm, and the base film 1 has a thickness of about 20 μm. For example, about 70
It is μm. That is, the total thickness of the adhesive tape 12 is about 90-μm. At this time, the height amount is set to, for example, 60 μm. In this case, this height amount is achieved by controlling the penetration depth of the blade 9 to 30 μm.

A scribing apparatus according to an embodiment of the present invention will be described with reference to FIGS. 2(A) and 2(B). Figure 2 (A) is a front view;
FIG. 2(B) is a surface measurement diagram.

One blade coated with diamond powder enters the semiconductor wafer 13 from above, cuts the semiconductor wafer 13, and enters the support film 11 below the semiconductor wafer.

Below the support film 11 is a laser light source 16 and a condensing system 1.
A measuring meter consisting of a light receiver 8 and a light receiver 17 is arranged. That is, when the laser light emitted from the light source 16 collides with the lower surface of the blade 19 and is reflected, the reflected scattered light is collected by the lens 18 and received by the light receiver 17. The height of the lower surface of the blade 19 is measured from the height position where the received light intensity is maximum.

Before the blade enters, as shown in Figure 2 (B),
By measuring the height of the interface between the semiconductor wafer 13 and the support film 11 in advance, when the blade 19 cuts the semiconductor wafer 13, the lower surface can be measured and the cutting status of the semiconductor wafer 13 can be monitored. can. By monitoring the cutting state of the semiconductor wafer placed on the adhesive tape in this manner, it is possible to maintain the semiconductor wafer scribing process and the scribing blade in an optimal state.

Although the present invention has been described above with reference to the embodiments, it will be obvious to those skilled in the art that the present invention is not limited to these, and that, for example, various modifications, improvements, combinations, etc. can be made.

[Effects of the Invention] As explained above, according to the present invention, a light source and a light receiver are disposed below the back surface of a semiconductor wafer, and the bottom surface of the semiconductor wafer and the bottom surface of the blade that cut the semiconductor wafer can be monitored. This allows the scribing process to be maintained in proper condition. Therefore, processing in subsequent steps becomes easier and throughput can be increased.

[Brief explanation of drawings]

1121(A) and 1121(B) are schematic cross-sectional views for explaining the wafer scribing process according to the embodiment of the present invention. FIGS. They are a schematic front view and a side view for explanation. In the figure, 1 2 3 6 7 8 Base film Adhesive material layer Semiconductor wafer Wafer Chuck Light source Receiver Blade Incident light Reflected light Semiconductor wafer Laser light source Light receiver Condensing system ([3] Bullet bottom surface measurement example i, Uni-hus scribe Figure 1 (A) Front view (B) Side scribing device Figure 2

Claims (3)

[Claims] (1) A method for scribing a semiconductor wafer into semiconductor chips, the wafer being supported on a base film (1) with an adhesive layer (2) on a wafer chuck (5) having a transparent portion (4). a step of placing a semiconductor wafer (3); and a step of placing a semiconductor wafer (3) supported on the base film (1).
The step of monitoring the height of the bottom surface of the semiconductor wafer (3) and the step of monitoring the height of the bottom surface of the semiconductor wafer (3) using the scribing blade (9).
), the height of the edge of the blade (9) is monitored when scribing the blade (9), and the blade (9) is scribed from the bottom surface of the base film (1) using the monitored height of the edge of the blade (9). A semiconductor wafer scribing method including a step of controlling the height to the edge. (2) The step of monitoring the height of the bottom surface of the semiconductor wafer (3) and the step of monitoring the height of the end of the blade (9) are performed on the transparent portion (4) of the wafer chuck (5).
2. The method for scribing a semiconductor wafer according to claim 1, wherein the method is performed by irradiating light through the base film (1) and detecting the reflected light. (3), wafer chuck (5) with transparent portion (4)
a light source (6) disposed below the wafer chuck (5);
and an optical measuring section including a light receiver (7), which can measure the height of the lower surface of an object by light reflection when the object is placed on the wafer chuck section. Wafer scribing equipment.