JP2009231435A - Method for manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture chips having a plurality of chip thicknesses without reducing a throughput and without increasing a manufacturing cost. <P>SOLUTION: The method for manufacturing the chip includes the steps of: making the wafer thickness into a first-thickness by cutting the backside of the wafer with a semiconductor circuit corresponding to a plurality of chips formed on the surface (a step S3); taking out the first-thickness chip from the wafer (a step S4); making the thickness of the wafer into a second-thickness by further cutting the backside of the wafer (a step S5); and taking out the second-thickness chip from the wafer (a step S6). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for manufacturing a semiconductor device in an assembly process.

In the conventional method of manufacturing a semiconductor device, the assembly process is performed according to the following flow.
FIG. 11 is a flowchart showing a conventional method for manufacturing a semiconductor device.
First, a surface protection tape is affixed to the pattern surface on which various semiconductor devices are formed in a single wafer state (step S80). Next, the wafer is ground from the back to a target chip thickness (step S81). Thereafter, the surface protection tape attached to the pattern surface is peeled off (step S82), and a dicing tape is attached to the back side of the wafer (step S83). And it divides | segments into a chip | tip using the dicing saw from the pattern surface side of a wafer (step S84). Thereafter, the adhesive force of the dicing tape is reduced by irradiating with ultraviolet rays (step S85). Then, the chip is peeled off from the dicing tape by being pushed up by the multi-point or one-point push-up pin from the back of the chip through the dicing tape, and the chip is vacuum-sucked by the collet and picked up (step S86). The picked-up chip is stored in a mounting substrate or in a tray.

Since the chip thickness required for mounting may be different, there is known a method of attaching a substrate having a different thickness to the chip and adjusting the chip thickness (see, for example, Patent Document 1).
By the way, in recent years, there has been an exposure technique (hereinafter referred to as multi-chip exposure) in which a pattern is transferred onto a wafer using a single reticle on which a plurality of different chip patterns are formed, for example when a small amount of a semiconductor device is prototyped. It has been used.

FIG. 12 is a diagram illustrating an example of multichip exposure.
The reticle 80a in FIG. 12A has 16 types of chip patterns having the same chip size, and is transferred onto the wafer 81 nine times.

The reticle 80b in FIG. 12B has three types of chip patterns with different chip sizes, and is transferred onto the wafer 82 nine times.
This makes it possible to manufacture a small amount of various types of chips.
JP 2004-207356 A

  However, when a different chip thickness is required for each type of chip, the conventional method as shown in FIG. 11 can only finish with one type of chip thickness for each wafer, so a different chip thickness is required. Chips are wasted. That is, a wasteful area increases on the wafer. In addition, wafers must be prepared according to the type of chip thickness required, which increases the number of wafers. As a result, there is a problem that the throughput is reduced and the manufacturing cost is increased.

  Accordingly, the present inventors have an object to provide a method for manufacturing a semiconductor device that can manufacture a plurality of chips having thicknesses without decreasing throughput and without increasing manufacturing costs.

  In order to achieve the above object, a semiconductor device manufacturing method including the following steps is provided. In this method of manufacturing a semiconductor device, a first grinding step of grinding a back surface of a wafer having a semiconductor circuit corresponding to a plurality of chips formed on the front surface to make the wafer thickness a first thickness, and the first grinding step After the first chip removing step of taking out the chip having the first thickness from the wafer, and after the first chip removing step, the back surface of the wafer is ground, and the wafer thickness is changed to the second thickness. A second grinding step, and after the second grinding step, a second chip taking step for taking out the chip having the second thickness from the wafer.

  Chips having a plurality of chip thicknesses can be manufactured without reducing the throughput and without increasing the manufacturing cost.

Hereinafter, the present embodiment will be described in detail with reference to the drawings.
FIG. 1 is a process flow diagram for explaining the flow of the semiconductor device manufacturing method according to the first embodiment.

2 and 3 are schematic views showing the state of each step in FIG.
In the wafer shown below, semiconductor circuits corresponding to a plurality of chips having different desired chip thicknesses are formed on the surface by, for example, multichip exposure. Each chip may be of a different type or size or the same type or size.

  First, as shown in FIG. 2A, a groove having a predetermined depth is formed between chips on a wafer 1 on which a plurality of chips are formed (half-cut dicing) (step S1). In half-cut dicing, the back surface of the wafer 1 is attracted to the chuck table 2 and cut by a dicing saw 3 from the pattern surface of the wafer 1 (surface on which semiconductor circuits are formed). The depth of the groove is set to a depth that can be divided into chips by back grinding (step S3) described later.

Next, as shown in FIG. 2B, the pattern surface of the wafer 1 is attached to the surface protection tape 5 with the frame 4 (step S2).
As the surface protection tape 5, for example, an ultraviolet curable type or a thermosetting type is used, in which the adhesive strength is lowered by applying ultraviolet irradiation or heat in a chip pickup process described later. A dicing tape or the like may be used.

  The frame 4 is to keep the shape by fixing the surface protection tape 5, and is attached to the outer periphery or the entire surface of the surface protection tape 5. The material of the frame 4 is not particularly limited as long as the shape of the surface protection tape 5 is maintained, such as metal.

  Thereafter, as shown in FIG. 3A, the wafer 1 attached to the surface protection tape 5 with the frame 4 is attracted to the chuck table 2. Then, the grindstone 6 or the chuck table 2 is rotated, and back grinding is performed from the back surface of the wafer 1 according to the thickest chip thickness among a plurality of desired chip thicknesses (step S3). For example, when a chip having a thickness of 300 μm and 200 μm is desired from a wafer having a thickness of 600 μm, back grinding is performed so that the wafer thickness becomes 300 μm. Thereby, the half-cut wafer 1 is divided into chips. At this time, the chip is affixed to the surface protective tape 5 and fixed.

The grindstone 6 used for back grinding may be a coarse one at the beginning and switched to a fine one on the way.
Next, the wafer 1 attached to the surface protection tape 5 with the frame 4 is set in a chip pickup device. Then, a chip having a desired thickness obtained by back grinding in step S3 is picked up from the divided wafer 1 (step S4). As shown in FIG. 3B, the chip pickup uses an ultraviolet laser 7 (or pulse heater) of the chip pickup device for the surface protection tape 5 of the chip portion to be picked up, using a mapping or infrared recognition device. Apply ultraviolet light (or heat) to lower the adhesive strength (stickiness). The adhesive strength of the surface protection tape 5 other than the chip portion to be picked up is maintained. Then, the chip is picked up by vacuum suction by the collet 8.

  A needleless type chip pickup apparatus may be used. In the manufacturing method of the semiconductor device according to the present embodiment, since the pattern surface of the wafer 1 is attached to the surface protective tape 5, it is desirable not to use the push-up pin method to protect this.

  Next, the wafer 1 affixed to the surface protection tape 5 with the frame 4 is taken out of the chip pickup device again and set on the chuck table 2 of the back grinding device as shown in FIG. Then, back grinding is performed to the next desired thickness (step S5). As in the above example, when a chip thickness of 300 μm and 200 μm is desired, in the second back grinding, grinding is performed so that the wafer thickness is 200 μm.

  Thereafter, in the same manner as in step S4, the chip is set in a chip pickup device, and a chip having a desired thickness obtained by back grinding in step S5 is picked up (step S6).

  In the above description, the method for manufacturing a semiconductor device when two types of chip thicknesses are required has been described. However, if the steps S3 and S4 (steps S5 and S6) are repeated, chips having three or more types of chip thicknesses can be easily obtained. It can be obtained from the same wafer.

  In this manner, in the method for manufacturing a semiconductor device according to the first embodiment, chips having a plurality of chip thicknesses required for mounting can be obtained from the same wafer. Therefore, there is no increase in the number of inserted wafers as in the prior art. Thereby, a decrease in throughput and an increase in manufacturing cost can be suppressed. And it becomes possible to ensure workability | operativity and product accuracy at the time of advancing a process, and can perform safe and reliable manufacture.

  In addition, since each process is performed using the surface protection tape 5 attached to the frame 4 while protecting the pattern surface, a process of dividing the wafer 1 into chips and then attaching it to a pickup tape or the like becomes unnecessary. As a result, it is not necessary to prepare a transfer device or a chip transfer device, the manufacturing cost can be reduced, and the risk of chip breakage or the like is reduced.

Next, a method for manufacturing the semiconductor device according to the second embodiment will be described.
FIG. 4 is a process flow diagram illustrating the flow of the manufacturing method of the semiconductor device according to the second embodiment.

5 and 6 are schematic views showing the state of each step in FIG.
The same components as those in the semiconductor device manufacturing method of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

First, as shown in FIG. 5A, the pattern surface of the wafer 1 is attached to the surface protection tape 5 with the frame 4 (step S10).
Next, as shown in FIG. 5B, the wafer 1 attached to the surface protection tape 5 with the frame 4 is adsorbed to the chuck table 2. Then, the grinding wheel 6 or the chuck table 2 is rotated, and back grinding is performed from the back surface of the wafer 1 according to the thickest chip thickness among a plurality of desired chip thicknesses (step S11). For example, when a chip having a thickness of 300 μm and 200 μm is desired from a wafer 1 having a thickness of 600 μm, back grinding is performed so that the wafer thickness becomes 300 μm.

  Thereafter, in order to divide the wafer 1 into chips, positioning is performed using infrared recognition or the like from the back side of the wafer 1, and as shown in FIG. 6 (A), full-cut dicing using a dicing saw 3 or Dicing using the laser 10 is performed (step S12). Since a certain amount of the wafer 1 is ground in the step S11, dicing here can shorten the time.

  Next, the wafer 1 attached to the surface protection tape 5 with the frame 4 is set in a chip pickup device. Then, a chip having a desired thickness obtained by back grinding in step S11 is picked up from the divided wafer 1 (step S13). As shown in FIG. 6B, the chip pickup is bonded by applying ultraviolet light (or heat) to the surface protection tape 5 of the chip portion to be picked up by the ultraviolet laser 7 (or pulse heater) of the chip pickup device. Reduce strength. The adhesive strength of the surface protection tape 5 other than the chip portion to be picked up is maintained. Then, the chip is picked up by vacuum suction by the collet 8.

  A needleless type chip pickup apparatus may be used. As in the first embodiment, since the pattern surface of the wafer 1 is attached to the surface protection tape 5, it is desirable not to use the push-up pin method.

  Next, the wafer 1 affixed to the surface protection tape 5 with the frame 4 is taken out of the chip pickup device again and set on the chuck table 2 of the back grinding device as shown in FIG. Then, back grinding is performed to the next desired thickness (step S14). As in the above example, when a chip thickness of 300 μm and 200 μm is desired, in the second back grinding, grinding is performed so that the wafer thickness is 200 μm.

  Thereafter, similarly to the process of step S13, the wafer 1 attached to the surface protection tape 5 with the frame 4 is set in a chip pickup device, and a chip having a desired thickness obtained by back grinding in step S14 is obtained. Pick up (step S15).

By repeating steps S14 and S15, chips having three or more kinds of chip thicknesses can be easily obtained from the same wafer.
Thus, even when half-cut dicing is not used, chips having a plurality of chip thicknesses required for mounting can be obtained from the same wafer. Therefore, there is no increase in the number of inserted wafers as in the prior art. Thereby, a decrease in throughput and an increase in manufacturing cost can be suppressed. And it becomes possible to ensure workability | operativity and product accuracy at the time of advancing a process, and can perform safe and reliable manufacture.

  In addition, since each process is performed using the surface protection tape 5 attached to the frame 4 while protecting the pattern surface, there is no need to replace the wafer 1 with chips after the wafer 1 is divided into chips. . This eliminates the need to prepare a transfer device and a chip transfer device, thereby reducing costs and reducing the risk of chip breakage.

  In addition, the process of step S11 and the process of step S12 may be interchanged, and the wafer 1 may be divided into chips before the back grinding. However, in that case, for example, it is desirable to reduce the grinding speed or use a fine grinding grindstone 6 so that the tip does not move during back grinding.

Next, a method for manufacturing the semiconductor device of the third embodiment will be described.
FIG. 7 is a process flow diagram illustrating the flow of the semiconductor device manufacturing method according to the third embodiment.

8, FIG. 9, and FIG. 10 are schematic views showing the state of each step in FIG.
The same components as those in the semiconductor device manufacturing method according to the first and second embodiments are denoted by the same reference numerals, and detailed description thereof is omitted.

  First, as shown in FIG. 8A, the surface protection tape 5a is attached to the surface of the wafer 1 without a frame (step S20). Thereafter, as shown in FIG. 8B, the wafer 1 to which the surface protection tape 5a is attached is attracted to the chuck table 2. Then, the grindstone 6 or the chuck table 2 is rotated, and back grinding is performed from the back surface of the wafer 1 according to the thickest chip thickness among a plurality of desired chip thicknesses (step S21). For example, when a chip having a thickness of 300 μm and 200 μm is desired from a wafer 1 having a thickness of 600 μm, back grinding is performed so that the wafer thickness becomes 300 μm.

  Thereafter, as shown in FIG. 9A, after the surface protective tape 5a is peeled off (step S22), the frame 4a similar to the frame 4 used in the semiconductor device manufacturing method of the first and second embodiments is used. The back surface of the wafer 1 is attached to the dicing tape 11 fixed in (Step S23). Then, as shown in FIG. 9B, full-cut dicing is performed from the pattern surface of the wafer 1 to divide the wafer 1 into chips (step S24). Since dicing is performed from the pattern surface, infrared recognition is not necessary. At this time, laser dicing may be performed as in the method of manufacturing the semiconductor device of the second embodiment.

  Next, as shown in FIG. 10A, the divided wafer 1 is separated from the dicing tape 11 into a frame 4b similar to the frame 4 used in the semiconductor device manufacturing method according to the first and second embodiments. The image is transferred to the surface protection tape 5b fixed in step S25a. Further, instead of the step S25a, as shown in FIG. 10B, a part of the wafer 1 divided by the chip transfer device is picked up and attached to the surface protection tape 5b fixed by the frame 4b. You may make it attach (step S25b). In that case, since the back surface of the wafer 1 is affixed to the dicing tape 11, it can be picked up using multi-point or one-point push-up pins 12 and a collet 8a. Then, the chip 1a having the desired thickness in the back grinding process in step S21 is stored in, for example, the chip tray 13, and the chip 1b having a desired thickness other than the chip 1b uses the collet 8a to protect the surface of the pattern. The dicing tape 11 is replaced with the tape 5b.

  Instead of the push-up pin 12, an ultraviolet laser, a pulse heater, or a needleless system as described in the semiconductor device manufacturing methods of the first and second embodiments may be used.

  If the step S25a is selected, then the wafer 1 attached to the surface protection tape 5b with the frame 4b is set in the chip pickup device. Then, a chip having a desired thickness obtained by back grinding in step S21 is picked up from the divided wafers 1 (step S26). This chip pickup process is the same as in the first and second embodiments described above. For example, the ultraviolet light (or heat) is applied to the surface protection tape 5b of the chip portion to be picked up by the ultraviolet laser 7 (or pulse heater) of the chip pickup device to lower the adhesive strength. The adhesive strength of the surface protection tape 5b other than the chip portion to be picked up is maintained. The chip is picked up by vacuum suction using the collet 8a, and the process proceeds to step S26.

  Next, the wafer 1 affixed to the surface protection tape 5b with the frame 4b is taken out of the chip pickup device again and set on the chuck table 2 of the back grinding device as shown in FIG. Then, back grinding is performed to the next desired thickness (step S27). As in the above example, when a chip thickness of 300 μm and 200 μm is desired, in the second back grinding, grinding is performed so that the wafer thickness is 200 μm.

  Thereafter, similarly to the process of step S26, the wafer 1 attached to the surface protection tape 5b with the frame 4b is set in a chip pickup device, and a chip having a desired thickness obtained by back grinding in step S27 is obtained. Pick up (step S28).

By repeating steps S27 and S28, chips having three or more kinds of chip thicknesses can be easily obtained from the same wafer.
As described above, in the method of manufacturing the semiconductor device according to the third embodiment, the process from step S20 to the process of step S24 is performed in the same manner as the conventional process. A chip having a chip thickness can be obtained. Therefore, there is no increase in the number of inserted wafers as in the prior art. Thereby, a decrease in throughput and an increase in manufacturing cost can be suppressed. And it becomes possible to ensure workability | operativity and product accuracy at the time of advancing a process, and can perform safe and reliable manufacture. Moreover, since it is possible to use the conventional equipment, capital investment can be reduced.

  Further, in the processes after steps S25a and S25b, the surface protection tape 5b fixed by the frame 4b is used to perform each process while protecting the pattern surface. Therefore, the divided wafer 1 is attached to a pickup tape or the like. A replacement process is not required. Thereby, conveyance between processes, setting to various manufacturing apparatuses, positioning, and back grinding can be easily performed, and the risk of chip breakage is reduced.

Regarding the above embodiment, the following additional notes are disclosed.
(Additional remark 1) The 1st grinding process which grinds the back of the wafer in which the semiconductor circuit corresponding to a plurality of chips was formed in the surface, and makes wafer thickness the 1st thickness,
After the first grinding step, a first chip removing step of taking out the chip of the first thickness from the wafer;
A second grinding step of grinding the back surface of the wafer after the first chip removing step to make the wafer thickness a second thickness;
After the second grinding step, a second chip removing step of taking out the chip of the second thickness from the wafer;
A method for manufacturing a semiconductor device, comprising:

(Appendix 2) Before the first grinding step, there is a step of forming grooves between the plurality of chips from the surface of the wafer, and then a step of attaching a protective tape to the surface of the wafer,
2. The method of manufacturing a semiconductor device according to claim 1, wherein the wafer is divided into the chips by grinding in the first grinding step.

(Appendix 3) A step of attaching a protective tape to the surface of the wafer before the first grinding step;
The method of manufacturing a semiconductor device according to claim 1, further comprising a step of dividing the wafer into the chips from the back surface after the first grinding step and before the first chip removing step.

  (Supplementary Note 4) After the first grinding step and before the first chip take-out step, a step of dividing the wafer from the surface into the chips, and protection on the surface of the wafer divided into the chips A method for manufacturing a semiconductor device according to appendix 1, wherein the method includes a step of applying a tape.

  (Supplementary Note 5) After the first grinding step, the method includes a step of dividing the wafer from the surface into the chips, and a step of attaching a protective tape to the surface of the wafer divided into the chips. 2. The method of manufacturing a semiconductor device according to appendix 1, wherein the first chip removal step is performed when a tape is applied.

  (Additional remark 6) The said 1st grinding process, the said 1st chip | tip pick-out process, the said 2nd grinding process, and the said 2nd chip pick-out process are performed with the said protective tape affixed on the said wafer surface. 4. A method for manufacturing a semiconductor device according to 2 or 3.

(Additional remark 7) The said protective tape is being fixed with the flame | frame, The manufacturing method of the semiconductor device as described in any one of additional remark 2 thru | or 6 characterized by the above-mentioned.
(Additional remark 8) The said 1st chip | tip taking-out process or the said 2nd chip | tip taking-out process adds light or heat locally to the said protective tape, and takes out the said chip | tip by reducing adhesiveness, It is characterized by the above-mentioned. The method for manufacturing a semiconductor device according to any one of appendices 2 to 7.

It is a process flow figure explaining a flow of a manufacturing method of a semiconductor device of a 1st embodiment. It is a schematic diagram which shows the mode of each process of FIG. 1 (the 1). It is a schematic diagram which shows the mode of each process of FIG. 1 (the 2). It is a process flow figure explaining a flow of a manufacturing method of a semiconductor device of a 2nd embodiment. It is a schematic diagram which shows the mode of each process of FIG. 4 (the 1). It is a schematic diagram which shows the mode of each process of FIG. 4 (the 2). It is a process flow figure explaining a flow of a manufacturing method of a semiconductor device of a 3rd embodiment. It is a schematic diagram which shows the mode of each process of FIG. 7 (the 1). It is a schematic diagram which shows the mode of each process of FIG. 7 (the 2). It is a schematic diagram which shows the mode of each process of FIG. 7 (the 3). It is a flowchart which shows the manufacturing method of the conventional semiconductor device. It is a figure which shows the example of multichip exposure.

Explanation of symbols

1 Wafer 2 Chuck Table 3 Dicing Saw 4 Frame 5 Surface Protection Tape 6 Grinding Wheel for Grinding 7 Ultraviolet Laser (or Pulse Heater)
8 Collet

Claims (5)

A first grinding step of grinding a back surface of a wafer having a semiconductor circuit corresponding to a plurality of chips formed on the front surface to make the wafer thickness a first thickness;
After the first grinding step, a first chip removing step of taking out the chip of the first thickness from the wafer;
A second grinding step of grinding the back surface of the wafer after the first chip removing step to make the wafer thickness a second thickness;
After the second grinding step, a second chip removing step of taking out the chip of the second thickness from the wafer;
A method for manufacturing a semiconductor device, comprising: Before the first grinding step, forming a groove between the plurality of chips from the surface of the wafer, and then attaching a protective tape to the surface of the wafer,
2. The method of manufacturing a semiconductor device according to claim 1, wherein the wafer is divided into the chips by grinding in the first grinding step. Attaching a protective tape to the surface of the wafer before the first grinding step;
2. The method of manufacturing a semiconductor device according to claim 1, further comprising a step of dividing the wafer into the chips from the back surface after the first grinding step and before the first chip removal step. .   After the first grinding step and before the first chip removal step, a step of dividing the wafer from the surface into the chips, and a protective tape is attached to the surface of the wafer divided into the chips The method of manufacturing a semiconductor device according to claim 1, further comprising: a step.   After the first grinding step, the method includes a step of dividing the wafer from the surface into the chips, and a step of attaching a protective tape to the surface of the wafer divided into the chips, and affixing the protective tape The method for manufacturing a semiconductor device according to claim 1, wherein the first chip removing step is performed.

Images