JPH02214609A - Method and device for dicing semiconductor wafer - Google Patents

Abstract

PURPOSE:To prevent the defective cutting of a semiconductor wafer positively and efficiently by using a dicing tape in which an optical layer having optical characteristics is formed to a surface layer section, detecting the change of light in a notch groove section notched to the dicing tape by a dicing blade and discriminating the suitability of the notch depth of the dicing blade. CONSTITUTION:With a dicing tape 4, a reflecting layer 9 reflecting light as a reflection characteristic layer is shaped between a base material layer 7 as a surface layer section 4a and an adhesive layer 8. The notch grooves 4b of the dicing tape 4 are irradiated with light from a light-emitting element 5 by a signal from a light-emitting element driver circuit 10. A receptor is composed of a reception-quantity detector 11 and a photo-detector 6, reflected light from the notch grooves 4b is received by the photo-detector 6, and the quantity of reflected light is detected by the reception-quantity detector 11. The reception-quantity detector 11 transmits a signal over a controller 12 when the quantity of reflected light suddenly increases from a stationary state, and the controller 12 preferentially selects the signal and controls a blade lifting driving section 13, and elevates a dicing blade 2 and stops the dicing blade.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method and apparatus for dicing a semiconductor wafer, in which a semiconductor wafer attached to a dicing tape is cut by cutting into the surface layer of the dicing tape with a dicing blade. .

[Conventional technology]

In conventional dicing, in order to completely separate each chip in the expansion process that follows the dicing process, the cut of the dicing blade is set to a depth that allows it to cut into the surface layer of the dicing tape. This enables complete cutting of semiconductor wafers.

[Problem to be solved by the invention]

In the conventional dicing described above, as the cutting of the semiconductor wafer progresses, the dicing blade itself wears out, etc.
The depth of cut of the dicing blade gradually becomes shallower, and after a certain point, the dicing blade no longer cuts the semiconductor wafer completely, resulting in poor cutting.

However, the above problem can be overcome by resetting the cutting edge of the dicing blade to the reference position after cutting a certain number of semiconductor wafers, or by replacing the dicing blade itself.

However, the wear of the dicing blade is not constant, and if the setting timing and replacement timing are determined by taking this into consideration for safety, it is assumed that waste will occur.

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor wafer dicing method and apparatus that can efficiently prevent semiconductor wafer cutting defects by making it possible to determine whether the depth of cut of a dicing blade is appropriate.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a semiconductor wafer dicing method in which a semiconductor wafer attached to a dicing tape is cut by cutting into the surface layer of the dicing tape with a dicing blade. Using a dicing tape formed on the dicing tape, the change in light at the cut groove portion cut into the dicing tape by the dicing blade is detected to determine whether the cutting depth of the dicing blade is appropriate.

Further, a dicing apparatus using this method includes a light emitter that can irradiate light to the cut groove portion of the dicing tape, a light receiver that can detect changes in reflected light of the light, and a surface layer of the dicing tape. A reflective layer having a reflective property for light was formed on the part.

Similarly, it is equipped with a light emitter that can irradiate light onto the cut groove portion of the dicing tape, and a light receiver that can detect changes in the transmitted light, and the surface layer of the dicing tape has transmission characteristics for light. A layer with transmission properties was formed.

[Effect]

By using a dicing tape in which an optical layer having optical properties is formed on the surface layer as in claim 1, the incision can be made in an appropriate cutting state in which the dicing blade cuts into the dicing tape and cuts off the optical layer. When an inappropriate cutting condition occurs in which the optical layer becomes too shallow to cut out, an optical change occurs in the light from the cut groove portion. Therefore, by detecting this change, it can be determined whether the cutting depth of the dicing blade is maintained appropriately.

Next, a case where the method according to claim 1 is implemented using the apparatus according to claims 2 and 3 will be explained.

The cutting edge of the dicing blade is set so that it can cut into the surface layer of the dicing tape, and the semiconductor wafer is cut, and at the same time, light is irradiated from the light emitter toward the cut groove portion of the dicing tape. As the dicing blade wears down after cutting a large number of semiconductor wafers, the cutting depth of the dicing blade relative to the dicing tape becomes shallower, and eventually the dicing blade no longer fully cuts the semiconductor wafer.

However, if a reflective layer having reflective properties is formed on the surface layer of the dicing tape as in claim 2, it is possible to detect whether or not the dicing blade has completely cut into the surface layer of the dicing tape as a change in the reflective characteristics. The dicing device can be detected, and based on the results, the operation of the dicing device can be continued or stopped.

Similarly, if a transmission layer having transmission characteristics is formed on the surface layer of the dicing tape, a light receiver can detect whether the dicing blade has completely cut into the surface layer of the dicing tape as a change in the transmission characteristics.

〔Example〕

A dicing apparatus embodying the present invention will be described below with reference to FIGS. 1 to 9.

As shown in FIG. 1, a dicing apparatus 1 includes a dicing blade 2 and a table 3, on which a dicing tape 4 is vacuum-adsorbed. The semiconductor wafer W is attached and fixed to the center of the upper surface of the dicing tape 4, and the semiconductor wafer W is cut by rotating the dicing tape 2 and moving the table 3.

To explain this in detail, the dicing blade 2 has a drive device (
(not shown) so that it can be rotated and moved up and down, and this drive device performs a downward movement to descend to a predetermined depth of cut at the start of cutting, and an upward movement to return to the original position after cutting, while rotating at high speed. repeat. On the other hand, the table 3 is also rotated by a drive device (not shown) and rotates in the XY axis directions.
That is, the dicing blade 2 is configured to be movable in both the cutting direction and one feeding direction, and immediately after the dicing blade 2 completes its descent, the semiconductor wafer W is moved in the opposite direction to the cutting direction. When the cutting for one row is completed, the cutting for the next row is started, so the semiconductor wafer W is moved to the original position and then moved one pitch in the opposite direction to the feeding direction. By repeating this process, the semiconductor wafer W is cut into strips. Next, the semiconductor wafer W cut into strips is rotated 90 degrees, and the dicing blade 2 and table 3 are operated in the same manner, thereby cutting the semiconductor wafer W into a grid pattern as shown in FIG. A chip Wa is formed.

In this case, the depth of cut into the semiconductor wafer W by the dicing blade 2 is set to such a depth that it can cut into the surface layer 4a of the dicing tape 4 in order to completely separate each chip Wa in the expansion process following the dicing process. Set. In addition, the cutting length in the cutting direction is such that the starting point and ending point of the dicing blade 2 are separated from the edge of the semiconductor wafer W and slightly outward so that the dicing blade 2 does not come into direct contact with the semiconductor wafer W when moving up and down. is set to be located.

Further, on the table 3, a light emitting element 5 constituting a light emitter and a light receiving element 6 constituting a light receiver are attached by fixing members (not shown). Light is irradiated onto the cut groove 4b in the portion outside the semiconductor wafer W. The irradiated light is reflected by the cut groove 4b and is received by the light receiving element 6.

As shown in FIG. 3, the dicing tape 4 has a reflective layer 9 that reflects light as a reflective layer between a base layer 7, which is the surface layer 4a of the dicing tape 4, and an adhesive layer 8, for example. The base layer 7 is a polymer film such as vinyl chloride, and the reflective layer 9 is a thin metal film deposited or sputtered on the polymer film. As a result, when the depth of cut into the dicing tape 4 by the dicing blade 2 is sufficient, the reflective layer 9 in the cut groove 4b is further cut away by the cut of the dicing blade 2, and the light from the cut groove 4b portion is reduced accordingly. The amount of reflection decreases, but eventually
When the dicing blade 2 wears and the cut becomes shallow and the reflective layer 9 of the cut groove 4b is no longer cut off by the dicing blade 2, the amount of light reflected from this portion increases. Therefore, if the amount of reflected light suddenly increases from a steady state, this indicates that the dicing blade 2 is no longer cutting into the reflective layer 9, and the depth of cut has become insufficient. .

If this is explained schematically based on FIGS. 4 and 5, the dicing blade 2 is worn out, and as shown in FIGS.
), (C), and (D), if the depth of cut 4b gradually becomes shallower, a cutting defect will occur in the semiconductor wafer W in the state of (D). On the other hand, the state of reflection of the light irradiated from the light emitting element 5 to the cut groove 4b is as shown in FIG. 5 (B).
In state (C), the amount of light reflected is small, but when state (C) is reached, the amount of light reflected suddenly increases. Therefore, if the dicing is stopped when the amount of reflection increases rapidly and the depth of cut is reset or the dicing blade 2 is replaced, defective cutting of the semiconductor wafer W can be prevented.

If this is specifically related to the control of the dicing apparatus 1, control as shown in FIG. 6 can be considered.

According to this, the light emitter is composed of the light emitting element drive circuit 10 and the light emitting element 5, and the light emitting element 5 is moved from the cut groove 4b of the dicing tape 4 by a signal from the light emitting element drive circuit 10.
light is irradiated on. The light receiver is composed of a received light amount detector 11 and a light receiving element 6. The light reflected from the cut groove 4b is received by the light receiving element 6, and the subsequent received light amount detector 11 detects the amount of reflected light. The received light amount detector 11 sends a signal to the controller 12 when the amount of reflected light suddenly increases from a steady state.
The controller 12 gives priority to this signal and controls the blade lifting drive section 13 to raise the dicing blade 2 and then stop it.

Note that in this embodiment, the surface layer 4a of the dicing tape 4
Although the reflective layer 9 is formed as a reflective layer in the above example, it may be used as an antireflection layer (for example, a thin film of magnesium fluoride is deposited on a polymer film such as vinyl chloride) to prevent reflection of light. In such a case, it can be detected that the depth of cut has become insufficient due to a sudden increase in the amount of reflection from a steady state.

Next, another embodiment of the present invention will be described with reference to FIGS. 7 and 8.

The dicing tape 4 of this embodiment has a non-transmissive layer, which is a transparent adhesive layer 8 laminated on the upper surface of the base material layer 7 constituting the surface layer 4a of the dicing tape 4, and a pigment that prevents the transmission of light. A transparent layer 14 is formed thereon.

Furthermore, a light emitting element 5 and a light receiving element 6 are attached to the top and bottom of the table 3 by fixing members (not shown). The non-transparent layer 14 in the groove 4b is cut by the dicing blade 2, and the amount of light transmitted from this portion is increased.

When the dicing blade 2 wears out and the cut becomes shallow and the non-transparent layer 14 of the cut groove is no longer cut by the dicing blade 2, the amount of light transmitted from this portion decreases. Therefore, when the amount of transmitted light suddenly decreases from a steady state, it means that the dicing blade 2 is no longer cutting into the non-transparent layer 14, and it can be confirmed that the cutting depth is insufficient.

Note that the reflective layer 9 and the non-transparent layer 14 may be formed by laminating them in the form of a film between the base material layer 7 and the adhesive layer 8 of the dicing tape 4, or by forming the reflective layer 9 and the non-transmissive layer 14 on the dicing tape 4 except for the part to which the semiconductor wafer W is attached. The adhesive layer 8 may be spread on the upper surface of the adhesive layer 8, or the adhesive layer 8 itself may be made of a material having predetermined reflection characteristics or transmission characteristics.

Further, the detection of reflected light is performed for one or more arbitrary cut grooves 4b on one semiconductor wafer W, or for each cut groove 4b as the case may be.

〔Effect of the invention〕

As described above, according to the present invention, the depth of cut of the dicing blade can be detected, and based on this detection result, it is possible to appropriately determine whether the depth of cut is appropriate, making it possible to stop or continue the dicing operation, and to This has the effect of reliably and efficiently preventing wafer cutting defects.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a dicing apparatus embodying the present invention, Fig. 2 is a plan view of a semiconductor wafer in a cut state, Fig. 3 is a cut side view of a dicing tape, and Fig. 4 shows the cutting state of a dicing blade. FIG. 5 is a cut side view showing the state of light reflection. FIG. 6 is a control flow diagram of the dicing device. FIG. 7 is a cut side view of the second embodiment of the dicing tape. The figure is a cut side view showing the state of transmission of light. 2... Dicing blade, 4... Dicing tape, 4a... Surface layer portion, 4b... Cut groove, 5...
Emitter, 6... Light receiver, 9... Reflective layer, 4... Non-transmissive layer, W... Semiconductor wafer.

Claims (1)

[Claims] 1. A semiconductor wafer dicing method in which a semiconductor wafer attached to a dicing tape is cut by cutting into the surface layer of the dicing tape with a dicing blade, comprising: an optical layer having optical properties on the surface layer; A method for dicing a semiconductor wafer, which comprises using a formed dicing tape and detecting a change in light in a cut groove portion cut into the dicing tape by a dicing blade to determine whether or not the cutting depth of the dicing blade is appropriate. . 2. In a semiconductor wafer dicing device that cuts a semiconductor wafer pasted onto a dicing tape by using a dicing blade to cut into the surface layer of the dicing tape, a light emitter that can irradiate light onto the cut grooves of the dicing tape, and a 1. A semiconductor wafer dicing apparatus, comprising: a light receiver capable of detecting changes in reflected light; and a reflective layer having a reflective property for light is formed on a surface layer of the dicing tape. 3. In a semiconductor wafer dicing device that cuts a semiconductor wafer pasted onto a dicing tape by using a dicing blade to cut into the surface layer of the dicing tape, a light emitter that can irradiate light onto the cut grooves of the dicing tape, and a 1. A semiconductor wafer dicing apparatus, comprising: a light receiver capable of detecting changes in transmitted light; and a light transmitting layer having a light transmitting characteristic formed on a surface layer of the dicing tape.