JPH11297650A - Manufacturing for semiconductor wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a semiconductor wafer, in which rigidity of a wafer is improved and the wafer is made thin easily. SOLUTION: In a bonding step, wafers 1a and 1b are bonded with a hot melt adhesive, and in this state the wafers are made thin in a grinding and polishing step. The wafers 1a and 1b are separated in a wafer flaking step. Since these wafers 1a and 1b are bonded, the whole thickness as a wafer is sufficient even when the wafers 1a and 1b become thinner as they are manufactured in the grinding and polishing step. Then, the grinding and polishing step can be carried out while the rigidity as a wafer is held adequately, and a sufficiently thin wafer is manufactured without a break in wafer during the grinding or polishing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor wafer.

[0002]

2. Description of the Related Art Conventionally, there are mechanical and chemical methods such as a grinding method, a polishing method (CMP), and an etching method as a thinning method of a semiconductor wafer used in, for example, a manufacturing process of an IC card chip wafer. . In these methods, as shown in FIG. 10, a tape for protecting a wiring pattern called an SG tape 32 is attached to the surface of a wafer 30 on which a wiring pattern 31 is printed, and then the wafer 3
0 is generally used as a method of shaving the back surface (surface opposite to the surface on which the wiring pattern 31 is provided).

[0003]

However, as the thickness of the wafer 30 is reduced, the rigidity of the wafer 30 itself is also reduced. When manufacturing wafers, there is a problem that the grinding force (or polishing force) of a grinding (or polishing) device exceeds the rigidity of the wafer itself during the manufacture of the wafer, and the wafer is destroyed. is there.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method of manufacturing a semiconductor wafer capable of easily reducing the thickness of the wafer by increasing the rigidity of the wafer itself. It is.

[0005]

According to the present invention, a first step of bonding a first wafer and a second wafer, and a step of bonding the first wafer and the second wafer are performed.
A second step of thinning the first wafer and the second wafer by shaving a non-bonding surface of the first wafer, and a second step of thinning the first wafer and the second wafer. And a third step of separating the wafer.

Accordingly, the thickness of the first wafer and the second wafer when the thinning is performed on the first wafer and the second wafer is reduced by the first wafer.
And the second wafer can be increased to a thickness of at least two wafers, so that the rigidity of the entire wafer can be improved by the increased thickness, and the high rigidity can be maintained. Therefore, there is an excellent effect that the thickness of the wafer can be easily reduced.

Further, in the invention according to claim 4, a first step of joining a reinforcing member for reinforcing rigidity and a wafer, and thinning the wafer by shaving a non-joining surface of the wafer. And a third step of peeling the thinned wafer from the reinforcing member. Thereby, the thickness of the wafer when thinning is performed on the wafer can be increased by the thickness of the reinforcing member, so that the rigidity of the entire wafer can be improved by the increased thickness. There is an excellent effect that the thickness of the wafer can be easily reduced while maintaining high rigidity.

Further, in the second, third and fifth aspects of the present invention, the protective member is used for joining the first wafer and the second wafer or joining the reinforcing member and the wafer. For example, it is possible to protect a wiring pattern provided on a wafer surface from dust generated by an adhesive or a thin-wall processing, and it is not necessary to provide a step for removing the wiring pattern, thereby simplifying the step. Has an excellent effect.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to the drawings. In this embodiment, a case will be described in which the present invention is applied to a method of thinning a wafer on which an IC chip built in a card is mounted. FIG. 1 is a process diagram for explaining a wafer thinning process according to a first embodiment of the present invention.

In the wafer bonding step shown in FIG. 1 (corresponding to the first step in claim 1), first, as shown in FIG. 3, the wafers 1a and 1b are respectively fixed to a vacuum type wafer chuck 5. And the wafers 1a, 1b
, The SG tapes 3a and 3b are adhered to the surface on which the wiring patterns 2a and 2b are printed, and a hot-melt hot melt adhesive 4 is applied to the non-adhered surface of the SG tape 3b. Then, the wafer chuck 5 is moved in the direction of the arrow shown in FIG. 3, and the wafers 1a and 1b are heated while being heated by a heating unit (not shown) provided on the wafer chuck 5, and then bonded together. 1a and the wafer 1b are fixed.

Next, in the grinding step shown in FIG. 1, the wafers 1a and 1b are ground by a grinding device 6 as shown in FIG.
That is, first, after fixing the wafer 1b side by the wafer chuck 5, the grinding device 6 provided with a grindstone on its surface is moved while rotating in the direction of the arrow shown in FIG.
The surface of a is ground. At this time, since the wafer chuck 5 is also rotating, the grinding device 6 can grind the entire surface of the wafer 1a. Note that grinding water for cleaning is poured from the nozzle 7 toward the boundary between the grinding device 6 and the wafer 1a.

Subsequently, when the grinding of the wafer 1a is completed, the fixing of the wafer 1b by the wafer chuck 5 is released, and the bonded wafers 1a and 1b are turned over by manual operation or the like. After being fixed, the surface of the wafer 1b is ground by the grinding device 6. When the grinding of the wafer 1b is completed, a polishing process for flattening the ground surface is performed as shown in FIG. That is, as shown in FIG. 5, first, the wafer 1b, which has just been ground in the previous process, is fixed to the wafer chuck 5, and then the wafer chuck 5 is released from fixing the wafer 1a.
Then, the wafer chuck 5 having the wafer 1b side fixed thereon is moved onto a polishing platen 8 having a polishing cloth provided on the surface thereof.
The surface of the wafer 1a is polished by being pressed against the polishing platen 8 while rotating in the direction of the arrow shown in FIG. The nozzle 9
From there, an abrasive for polishing is poured toward the polishing platen 8.

When the polishing of the wafer 1a is completed, the fixing of the wafer 1b by the wafer chuck 5 is released, and the bonded wafers 1a and 1b are turned over by hand or the like, and the wafer 1a side is fixed to the wafer chuck 5 this time. Then, the surface of the wafer 1b is polished by the polishing apparatus 8. The above-described grinding step and polishing step correspond to the second step in claim 1.

Next, in the cleaning & drying step shown in FIG. 1, dust generated in the grinding step and the polishing step and adhering to the wafers 1a and 1b is washed and then dried. Subsequently, in a wafer peeling step shown in FIG. 1 (corresponding to a third step in claim 1), the bonded wafers 1a and 1b are peeled using a peeling device 17 as shown in FIG. That is, after the wafer chuck 5 is fixed to both the wafers 1a and 1b, the wafers 1a and 1b are heated by a heating unit (not shown) until the temperature of the hot melt adhesive 4 is melted. Then, the wafer chuck 5 is moved in the X-axis, Y-axis, and U-axis directions shown in FIGS. 9A and 9B to separate the wafer 1a from the wafer 1b. And
The SG tapes 3a and 3b that were pasted are replaced with the wafer 1a,
1b, very thin wafers 1a, 1b
Is manufactured.

As described above, in the above-described embodiment, the two wafers 1 are used at the stage of the pre-process leading to the grinding process and the polishing process.
a and 1b are bonded together, and the grinding and polishing steps are performed thereon. Therefore, even if the thickness of the wafers becomes thinner as the grinding and polishing steps progress, the wafers are stacked because the two wafers are stacked. It has a sufficient thickness as a whole. Therefore, the grinding process and the polishing process can be performed while maintaining a sufficient rigidity of the entire wafer, and an extremely thin wafer can be manufactured without breaking the wafer during grinding or polishing. .

Further, by stacking two wafers as in the above embodiment, the strength of the whole wafer itself is maintained at a high level, so that the warpage of the wafer can be prevented or the wafer can drop during the transfer. This can prevent breakage of the wafer. In the first embodiment,
Although an example in which two surfaces of the two bonded wafers 1a and 1b are ground or polished has been described, the invention is not limited thereto.
For example, as shown in FIG. 6, a side surface of a wafer 12 on which wafers 1a and 1b are bonded is fixed by a carrier 11, and both surfaces of the wafer 12 are simultaneously ground by grinding devices 10a and 10b provided with a grindstone on the surface. Is also good. Also,
In the polishing step, as shown in FIG.
1b is fixed by a carrier 13 on a side surface of a wafer 12, and a polishing device 14a,
4b, both surfaces of the wafer 12 may be polished simultaneously.

By simultaneously polishing or polishing both surfaces of the wafer 12, the efficiency of the manufacturing process can be improved. Further, in the grinding step and the polishing step, the thinning may be performed not by a mechanical method but by a chemical method using an etchant poured from a nozzle 16 as shown in FIG. The member 15 is a member for preventing the etchant from flowing around.

Next, a second embodiment will be described. In this embodiment, instead of bonding two wafers as in the first embodiment, one wafer is bonded to an iron plate for reinforcing the rigidity of the wafer. In the iron plate bonding step shown in FIG. 2 (corresponding to the first step in claim 4), similarly to the first embodiment, first, the wafer 21 and the iron plate 25 are fixed to the wafer chuck 5, respectively. Then, the SG tape 23 is attached to the surface on which is printed, and then a hot-melt hot melt adhesive 24 is applied to the non-attached surface of the SG tape 23. Then, the wafer 21 is adhered to the iron plate 25 by applying pressure while heating the wafer 21 by a heating unit (not shown) provided in the wafer chuck 5, and thereafter, the whole is cooled to fix the gap between the wafer 21 and the iron plate 25.

Next, in the grinding step and the polishing step (corresponding to the second step in claim 4) shown in FIG.
Grinding and polishing are performed only on the wafer 1, and in the subsequent cleaning & drying step, the wafer 2 generated in the grinding step and the polishing step is removed.
The dust adhering to 1 is washed and then dried. And
In the wafer peeling step shown in FIG. 2 (corresponding to the third step in claim 4), the wafer 21 and the iron plate 25 are peeled off, and the SG tape 23 that has been pasted is peeled off from the wafer 21 to have an extremely small thickness. A wafer is manufactured.

According to the second embodiment, since it is not necessary to grind both surfaces, the process can be simplified as compared with the first embodiment.

[Brief description of the drawings]

FIG. 1 is a process diagram for explaining a wafer thinning process according to a first embodiment of the present invention.

FIG. 2 is a process diagram illustrating a wafer thinning process according to a second embodiment of the present invention.

FIG. 3 is an explanatory diagram for explaining a bonding step in the first embodiment.

FIG. 4 is an explanatory diagram for explaining a grinding step in the first embodiment.

FIG. 5 is an explanatory diagram for explaining a polishing step in the first embodiment.

FIG. 6 is an explanatory diagram for explaining another grinding step in the first embodiment.

FIG. 7 is an explanatory diagram for explaining another polishing step in the first embodiment.

FIG. 8 is an explanatory diagram for explaining still another grinding step in the first embodiment.

FIG. 9 is an explanatory diagram for explaining a wafer peeling step in the first embodiment.

FIG. 10 is an explanatory diagram for explaining a conventional technique.

[Explanation of symbols]

 1a, 1b Wafer 2a, 2b Wiring pattern 3a, 3b Tape for SG 4 Hot melt adhesive

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Fumiyoshi Kano 1-1-1, Showa-cho, Kariya-shi, Aichi Pref. Inside DENSO Corporation (72) Inventor Kiyoshi Nakakugi 1-1-1, Showa-cho, Kariya-shi, Aichi Pref. Inside DENSO

Claims (5)

[Claims] A first step of bonding a first wafer and a second wafer; and a step of cutting a non-bonding surface of the first wafer and the second wafer to form the first wafer and the second wafer. A second step of performing thin processing on the second wafer, and a third step of peeling off the first wafer and the second wafer that have been subjected to thin processing. Wafer manufacturing method. 2. The method according to claim 1, wherein the first step includes: attaching a protection member for protecting the wiring pattern on a wiring pattern provided on one surface of each of the first wafer and the second wafer; 2. The method of manufacturing a semiconductor wafer according to claim 1, further comprising: a joining step of joining the protection members attached to each of the first wafer and the second wafer. 3. 3. The first step, wherein a protection member for protecting the wiring pattern is sandwiched between each surface of the first wafer and the second wafer provided with the wiring pattern, 2. The method of manufacturing a semiconductor wafer according to claim 1, further comprising: bonding the first wafer and the second wafer. 3. 4. A first step of joining a reinforcing member for reinforcing rigidity and a wafer, and a second step of thinning the wafer by shaving a non-joining surface of the wafer. A third step of separating the thinned wafer from the reinforcing member. 5. The method according to claim 1, wherein the first step comprises: attaching a protection member for protecting the wiring pattern on a wiring pattern provided on one surface of the wafer; and attaching the protection member to the wafer. The method for manufacturing a semiconductor wafer according to claim 4, further comprising: a bonding step of bonding the reinforcing member.