JP2865336B2 - Semiconductor wafer scribing method and scribing apparatus - Google Patents

Description

The present invention relates to a method and an apparatus for scribing a semiconductor wafer into semiconductor chips, and to appropriately maintain a height from a lower surface of an adhesive tape supporting a semiconductor wafer to a lower surface of a scribing blade. A method for scribing a semiconductor wafer into semiconductor chips, comprising: a semiconductor chuck supported on a base film provided with an adhesive layer on a wafer chuck having a transparent portion; Placing the wafer, monitoring the height of the bottom surface of the semiconductor wafer supported on the base film, and monitoring the height of the end of the blade when the semiconductor wafer is scribed by a scribing blade. And from the bottom surface of the base film using the height of the monitored blade end. It is configured to include a step of controlling the height amount up to the blade end.

The present invention relates to a wafer scribe in a manufacturing process of a semiconductor device, and more particularly to a method and an apparatus for scribing a semiconductor wafer on a semiconductor chip. After manufacturing a large number of semiconductor integrated circuits on a semiconductor wafer, the semiconductor wafer is scribed into a large number of semiconductor chips. In the scribing process, the semiconductor wafer is stuck on an adhesive tape and cut from above. At this time, it is desired to control the height from the lower surface of the adhesive tape to the lower 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, and after performing a scribing process, a height amount is measured, and a desired height amount is obtained based on measurement data. The height for scribing was controlled. However, when a large number of wafers are processed, variations in the height amount occur due to wear of the blades of the scribing device and variations in the thickness of the wafer adhesive tape.

[Problems to be Solved by the Invention] According to the conventional technique described above, in the scribing process of the semiconductor wafer, the height amount has been varied. Since the scribing process has not been completed, the semiconductor chip cannot be separated or the chip of the semiconductor chip is generated because the scribing step has not been completed. There is a DDB process in which each semiconductor chip is pushed up from below after the scribing process, sucked up with a chuck or collet, and diced on the lead frame. If the adhesive strength is high, poor suction will occur. Although the adhesive strength can be reduced by irradiation with ultraviolet rays or the like, it cannot cope with variations, and in some cases, the blade may directly damage the wafer chuck.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for scribing a semiconductor wafer capable of appropriately maintaining a height from a lower surface of an adhesive tape supporting a semiconductor wafer to a lower surface of a scribing blade.

Another object of the present invention is to provide a scribe device capable of performing the above-described method for scribing a semiconductor wafer.

[Means for Solving the Problems] In order to solve the above problem, a scribe blade is formed by irradiating light from the lower surface of a semiconductor wafer, reflecting the light on the lower surface of a semiconductor wafer scribing blade, and detecting the reflected light. 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 height can be monitored and controlled during the scribing process, the height can be stably controlled to a desired value.

Therefore, it is possible to prevent inconvenience due to uneven cutting depth of the blade due to variation in the height amount.

Embodiment FIGS. 1A and 1B show an embodiment of the present invention. A window 4 made of a transparent material is provided on a part of the wafer chuck 5.
, And a photometer 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 a semiconductor wafer 3 adhesively supported by the adhesive layer 2 are arranged on the window 4. You. That is, the semiconductor wafer 3 is attached to the base film 1 by the adhesive layer 2, and the base film 1 is held on the wafer chuck 5 by the negative pressure of a vacuum chuck appropriately provided on the wafer chuck 5, such as a laser. Light source 6
The light 11 is emitted from the semiconductor wafer 3 and condensed by a lens or the like as necessary, and irradiates the lower surface of the semiconductor wafer 3. The reflected light 12 on the lower surface of the semiconductor wafer 3 is condensed by a lens or the like and received by the light receiver 7.
For example, while irradiating the collimated laser beam to the lower surface of the semiconductor wafer 3, the light receiver 7 having a fixed focus lens
Is scanned in the height direction, a 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. 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 light reflected from both surfaces can be used. The height measurement using light is not limited to these methods.

As shown in FIG. 1B, the semiconductor wafer 3 thus prepared is scribed by a blade 9.
In the scribing process, the scribing blade 9 is used.
Grinds the semiconductor wafer 3 and reaches the lower adhesive material layer 2 and the upper layer of the base film 1. The lower surface of the blade 9 which penetrates through the semiconductor wafer 3 and emerges from the light source 6
Irradiate 11 and monitor. That is, the tip 12 where the light beam 11 is reflected by the lower surface of the blade 9 is received by the light receiver 7 and the height of the lower surface of the blade 9 is monitored. Thereby, the height H can be calculated 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.

For example, the blade for semiconductor wafer scribing is a blade having a width of about 60 μm and a height of about 1.2 mm, the semiconductor wafer 3 has a thickness of about 490 μm, and the adhesive layer 2 has a thickness of, for example, 20 μm.
The thickness of the base film 1 is, for example, about 70 μm.
That is, the thickness of the adhesive tape 1.2 is about 90 μm in total. At this time, for example, 60 μm is set as the height amount. In this case, this height amount is realized by controlling the penetration depth of the blade 9 to 30 μm.

A scribe device according to an embodiment of the present invention will be described with reference to FIGS. FIG. 2 (A) is a front view, and FIG. 2 (B) is a side view. A blade 19 coated with diamond powder enters from above the semiconductor wafer 13, cuts the semiconductor wafer 13, and enters the support film 11 below the semiconductor wafer. Below the support film 11, a measuring instrument including a laser light source 16, a light collecting system 18, 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, the height of the interface between the semiconductor wafer 13 and the support film 11 is measured in advance as shown in FIG. By measuring the lower surface of the semiconductor wafer 13, the cutting state of the semiconductor wafer 13 can be monitored. In this manner, by monitoring the cutting state of the semiconductor wafer placed on the adhesive tape, the semiconductor wafer scribing step and the scribing blade can be maintained in the optimum state.

Although the embodiments have been described above, the present invention is not limited to these embodiments. For example, various changes, improvements,
It will be obvious to those skilled in the art that combinations and the like are possible.

[Effects of the Invention] As described above, according to the present invention, a light source and a light receiver are arranged below the back surface of a semiconductor wafer, and the lower surface of the semiconductor wafer and the lower surface of the blade that cut the semiconductor wafer are monitored. Thereby, the scribing step can be maintained in an appropriate state. Therefore, the processing in the subsequent steps is facilitated, and the throughput can be increased.

[Brief description of the drawings]

1A and 1B are schematic cross-sectional views for explaining a wafer scribing process according to an embodiment of the present invention, and FIGS. 2A and 2B are diagrams illustrating a scribing apparatus according to an embodiment of the present invention. It is the schematic front view and side view for description. In the figure, 1 ... Base film 2 ... Adhesive layer 3 ... Semiconductor wafer 5 ... Wafer chuck 6 ... Light source 7 ... Light receiver 9 ... Blade 11 ... Incident light 12 ... Reflected light 13 ... Semiconductor wafer 16 Laser light source 17 Photodetector 18 Focusing system 19 Blade

Claims (3)

(57) [Claims] 1. A method for scribing a semiconductor wafer into semiconductor chips, comprising: a wafer chuck (5) having a transparent portion (4), supported on a base film (1) having an adhesive layer (2). Disposing the semiconductor wafer (3), monitoring the height of the bottom surface of the semiconductor wafer (3) supported on the base film (1), and scribing the semiconductor wafer (3) with a scribing blade (9). 3) monitoring the height of the end of the blade (9) when scribing 3); and using the monitored height of the end of the blade (9) to cut the blade (9) from the lower surface of the base film (1). A method for scribing a semiconductor wafer including a step of controlling a height amount to an end. 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) comprise a 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 and the base film and detecting reflected light. 3. A wafer chuck (5) having a transparent portion (4), and a light source (6) disposed below the wafer chuck (5).
And a light measuring unit including a light receiver (7), which can measure the height of the lower surface of the wafer or blade by light reflection when the wafer or the blade is disposed on the wafer chuck unit. Scribing device for semiconductor wafers.