JP4001661B2 - Wafer mounting table, wafer back surface processing method, exposure apparatus, and spin coating apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wafer mounting table and a wafer back surface processing method, and more particularly to a wafer mounting table provided in a semiconductor device manufacturing apparatus such as an exposure stepper and a wafer back surface performed as a pre-process in each manufacturing process of the semiconductor device. It relates to the processing method.
[0002]
[Prior art]
A stage of an exposure stepper used in a semiconductor device manufacturing process is provided with a wafer mounting table for mounting a wafer on a moving stage that moves in the XY direction. As shown in FIG. 8, the wafer mounting table 1 has a concentric suction groove 13 formed on the mounting surface 12 side of the wafer W in the base 11, and a suction tube 14 is connected to the bottom surface of the suction groove 13. It has a configuration. In the wafer mounting table 1 configured as described above, the suction groove 13 is blocked by the mounted wafer W. Then, the inside of the suction groove 13 connected to the suction tube 14 becomes negative pressure, and the wafer W is fixed on the base 11 by vacuum suction.
[0003]
[Problems to be solved by the invention]
However, the wafer mounting table has the following problems. That is, particles may adhere to the back side of the wafer placed on the wafer placement table. In such a case, when the wafer is mounted on the wafer mounting table and fixed by vacuum suction, as shown in FIG. 9 (cross-sectional view taken along the line AA ′ in FIG. 8), the wafer W to which the foreign matter a is attached. A pressure is locally applied to the portion, and only the wafer W portion is lifted. For this reason, there has been a problem that during the exposure, only the portion of the wafer W is out of focus, and normal pattern exposure cannot be performed.
[0004]
Further, not only the wafer mounting table of the exposure stepper, but also the wafer mounting table of the spin coater, for example, when the wafer is locally lifted only on the part where the particles are adhered as described above, the coating film on the wafer is formed. The problem of thinning locally occurs.
[0005]
[Means for Solving the Problems]
The present invention for solving the above problems is a wafer mounting table and a method for processing a wafer back surface. In particular, the wafer mounting table according to the first invention is a top surface side of a base on which a wafer is fixedly mounted by vacuum suction. The surface layer is made of a low-viscosity resin. The wafer mounting table according to the second invention is characterized in that a low-viscosity resin layer is provided on a base on which a wafer is fixedly mounted by sandwiching.
[0006]
In each of the above wafer mounting tables, since the surface on which the wafer is fixedly mounted is made of a low-viscosity resin, the uneven shape on the back surface side (mounting surface side) of the wafer mounted on the base is low. Absorbed with viscous resin. For this reason, even when foreign matter is attached to the back side of the wafer, the adhesion shape of the foreign matter is absorbed by the low-viscosity resin, and the pressure caused by foreign matter sandwiched between the wafer mounting table and the wafer is applied to the wafer. There is no participation. Therefore, the surface side of the wafer is kept flat.
[0007]
The wafer mounting table according to a third aspect of the present invention is a wafer mounting table having a support provided so as to be able to protrude from the base while supporting the wafer, and an adhesive material layer on the base. And the support is made to protrude upward from the adhesive material layer. The wafer back surface processing method of the present invention is a wafer back surface processing method using the wafer mounting table of the third invention, and the wafer is placed on the adhesive material layer in a state where the support is lowered. Next, the support tool is raised and the wafer on the adhesive material layer is supported on the support tool.
[0008]
In the wafer mounting table, an adhesive material layer is provided on the base, and a support tool is provided so as to protrude freely from the adhesive material layer. Therefore, in a state where the support tool is buried in the adhesive material layer, The wafer is placed on the adhesive material layer, and the wafer is supported by the support in a state where the support is lowered and protruded from the adhesive material layer.
[0009]
In the wafer back surface processing method, after the wafer is placed on the adhesive material layer, the support is lifted so that the wafer is supported on the support, so that foreign matter is present on the back side of the wafer. When adhered, the foreign matter is adhered to the adhesive material layer, and the foreign matter is removed from the back surface of the wafer.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments to which a wafer mounting table and a wafer back surface processing method of the present invention are applied will be sequentially described with reference to the drawings.
The wafer mounting table described here is provided on a stepper stage of an exposure apparatus used in the manufacturing process of a semiconductor device or in a spin coating apparatus, and the wafer back surface processing method is an exposure process or rotation in the manufacture of a semiconductor device. Suppose that it is performed as a pretreatment of a film forming process by coating.
[0011]
(First embodiment)
FIG. 1 is a plan view of the wafer mounting table of the first embodiment, and FIG. 2 is a cross-sectional view taken along the line AA ′ of FIG. The configuration of the wafer mounting table of the first embodiment will be described below based on these drawings. As shown in the drawing, the wafer mounting table 2 of the first embodiment has a base 21 and an adsorption groove 23 provided on the upper surface 22 side of the base 21, and a suction tube 24 is connected to the adsorption groove 23. This is a vacuum suction type mounting table. In particular, the wafer mounting table 2 has a structure in which grooves 25 are provided between the suction grooves 23 on the upper surface side of the base 21 and the grooves 25 are filled with a low-viscosity resin 26.
[0012]
The base 21 of the wafer mounting table 2 is made of, for example, a metal material that is small in shrinkage due to heat. The suction groove 23 is concentrically provided on the upper surface 22 side of the base 21, and the suction pipe 24 is connected to the bottom surface of each suction groove 23.
[0013]
The grooves 25 provided between the suction grooves 23 are concentrically provided on the upper surface 22 side of the base 21. The groove 25 is provided in a state of being completely partitioned from the adsorption groove 23 by the side wall formed by the base 21. By providing the groove 25 and filling the inside thereof with the low-viscosity resin 26 in this manner, leakage from the groove 25 into the suction groove 23 when the wafer W is placed is prevented, and the wafer W in the suction groove 23 is prevented. The low-viscosity resin 26 is efficiently disposed on the surface layer of the base 21. Moreover, the groove | channel 25 shall be provided in as wide an area as possible.
Further, as the low-viscosity resin 26 filled in the groove 25, for example, an adhesive gel-like resin such as an acrylic resin or a polyethylene resin, and a hydrophobic property that weakens the adhesiveness such as a glass fiber or a fluororesin. It is preferable to use a mixture of these resins.
[0014]
According to the wafer mounting table 2 configured as described above, the suction groove 23 is closed by mounting the wafer W on the base 21, and the inside of the suction groove 23 is hidden by suction from the suction pipe 24. Due to the pressure, the wafer W is attracted and fixed to the upper surface of the base 21. Here, when the foreign matter a adheres to the back surface (mounting surface) side of the wafer W, the foreign matter a is absorbed by the low-viscosity resin 26 on the surface layer of the base 21 or in the suction groove 23. To be absorbed. At this time, since the low-viscosity resin 26 is provided between each of the plurality of suction grooves 23, the foreign matter a on the back surface of the wafer W can be efficiently absorbed into the low-viscosity resin 26. Therefore, the possibility that pressure is applied to the wafer W can be reduced by the foreign object a being sandwiched between the wafer W and the wafer mounting table 2. For this reason, even if the foreign material a adheres to the back surface of the wafer W, the surface of the wafer W is prevented from being locally affected by the influence, and the surface of the wafer W is kept flat.
[0015]
Therefore, in the exposure apparatus provided with the wafer mounting table 2, exposure can be performed with a good focus state over the entire surface of the wafer W even if foreign matter adheres to the back surface of the wafer W. Further, in the spin coater provided with the wafer mounting table 2, a coating film having a uniform film thickness can be formed on the entire surface of the wafer W. The same applies to a case where a non-removable convex portion due to scratches or the like is formed on the back surface of the wafer W. In addition, when a cleaning process for removing foreign matters is performed before the exposure process or the film forming process, this cleaning process becomes unnecessary, and the manufacturing process of the semiconductor device is simplified.
[0016]
Note that the low-viscosity resin 26 may have adhesiveness. This is another embodiment of the first embodiment . In this case, the adhesiveness of the low-viscosity resin 26 is set such that the low-viscosity resin 26 does not adhere to the back surface of the wafer W. As the low-viscosity resin 26 having such an adhesive property, for example, an acrylic resin or a polyethylene resin is preferably used.
[0017]
As described above, since the low-viscosity resin 26 is made adhesive, when the wafer W is removed from the wafer mounting table 2, the foreign matter a on the back surface of the wafer W is adhered to the low-viscosity resin 26. It becomes possible to remove from the back surface of W. Therefore, it is possible to prevent the wafer W transfer system and the manufacturing apparatus used in the next process from being contaminated by the foreign matter a.
[0018]
The wafer mounting table 2 may be configured in a thin plate shape. The thin plate-like wafer mounting table is provided with a suction groove 23, a suction tube 24 connected to the suction groove 23, a groove 25, and a low-viscosity resin 26 filled therein. Then, the thin plate-like wafer mounting table is mounted and used on a conventional vacuum suction type wafer mounting table (not shown) in a state where the suction tube is communicated. As a result, when the fluidity of the low-viscosity resin 26 is impaired, or when many foreign substances are adhered to the low-viscosity resin 26 having adhesiveness and the adhesiveness is impaired, the thin plate-like wafer mounting table is replaced. Thus, the function of the wafer mounting table 2 can be recovered.
[0019]
(Second Embodiment)
FIG. 3 is a perspective view of the wafer mounting table of the second embodiment, and FIG. 4 is a cross-sectional view taken along the line AA ′ in a state where the wafer is mounted on the wafer mounting table of FIG. The configuration of the wafer mounting table of the second embodiment will be described below based on these drawings. As shown in the figure, the wafer mounting table 3 includes a base 31 and fixing pins 33 erected in a state of protruding from the upper surface 32 of the base 31. In particular, the wafer mounting table 3 is provided with a low-viscosity resin layer 34 on the upper surface 32 of the base 31, and the fixing pins 33 are provided so as to protrude above the low-viscosity resin layer 34. Further, the wafer mounting table 3 may be provided with a support 35 provided so as to protrude from the low-viscosity resin layer 34 while supporting the wafer W.
[0020]
The base 31 is made of the same material as the base (21) of the first embodiment described with reference to FIGS. 1 and 2, and the upper surface 32 is more than the wafer W to be placed. It has a sufficiently wide area.
In addition, one fixing pin 33 is provided in each of the guide holes 33a provided in the base 31 in the state from the periphery of the wafer W toward the center at the position where the periphery of the wafer W is equally divided into three. This is established. Each fixing pin 33 is provided so as to be movable from the periphery of the wafer W toward the center along the guide hole 33a while maintaining a state in which the fixing pin 33 protrudes upward from the low viscosity resin layer 34. Yes.
[0021]
The low-viscosity resin layer 34 is formed, for example, in a substantially circular shape that is slightly smaller than the wafer W, and is provided in a portion surrounded by the three fixing pins 33 on the base 31. The low-viscosity resin layer 34 is composed of a mixed material of a gel-like resin having adhesiveness such as acrylic resin or polyethylene resin and a hydrophobic resin that weakens adhesiveness such as glass fiber or fluororesin. The The low-viscosity resin layer 34 is provided with the low-viscosity resin layer 34 on the upper surface of the base film 34b provided with the adhesive layer 34a on the back side so that the adhesive layer 34a can be easily replaced. It is assumed that it is provided on the base 31 by being adhered to the base 31. However, the low viscosity resin layer 34 may be provided directly on the base 31 when it is not necessary to consider the trouble of replacement.
[0022]
Further, the support 35 is composed of, for example, three pins, and is configured to support the wafer W on the surface constituted by each pin. And the hole pattern 36 is formed in the protrusion part of the support tool 35 so that the protrusion of this support tool 35 is possible in the said low-viscosity resin layer 34 and the said base 31. As shown in FIG.
[0023]
According to the wafer mounting table 3 having the above-described configuration, the wafer W is lowered and buried in the low-viscosity resin layer 34 while the wafer W is supported on the support 35, so that the wafer W becomes low-viscosity resin. Placed on layer 34. In this state, when the fixing pin 33 is moved toward the center of the wafer W, the wafer W is fixed in a state where the wafer W is sandwiched between the fixing pins 33. Here, when the foreign material a adheres to the back surface (mounting surface) side of the wafer W, the foreign material a is absorbed by the low viscosity resin layer 34. For this reason, the foreign substance a is sandwiched between the wafer W and the wafer mounting table 3 to completely prevent the wafer W from being pressurized. Therefore, the same effect as the wafer mounting table (2) of the first embodiment can be obtained. Moreover, in the state where the wafer W is placed, almost all the back surface of the wafer W comes into contact with the low-viscosity resin layer 34 and the convex shape of the back surface of the wafer W can be completely absorbed. In this way, a descent that keeps the surface of the wafer W flat can be obtained.
[0024]
Note that the low-viscosity resin layer 34 may have adhesiveness. This is another embodiment of the second embodiment . In this case, the adhesiveness of the low-viscosity resin layer 34 is such that the low-viscosity resin does not adhere to the back surface of the wafer W, and the adhesive force is weaker than that of the adhesive layer 34a. As a substance constituting the low-viscosity resin layer 34 having such adhesiveness, for example, an acrylic resin or a polyethylene resin is preferably used.
[0025]
As described above, the adhesion to the low-viscosity resin layer 34 prevents the wafer transfer system and the manufacturing apparatus used in the next process from being contaminated by the foreign matter a, as in the first embodiment. it can.
[0026]
(Third embodiment)
FIG. 5 is a perspective view of the wafer mounting table of the third embodiment, and FIG. 6 is a cross-sectional view taken along the line AA ′ in a state where the wafer is mounted on the wafer mounting table of FIG. The configuration of the wafer mounting table of the third embodiment will be described below based on these drawings. As shown in the figure, the wafer mounting table 4 includes a base 41 and a support 43 provided so as to protrude from the upper surface 42 of the base 41 while supporting the wafer W. In particular, the wafer mounting table 4 is provided with an adhesive material layer 44 on the upper surface 42 of the base 41, and the support 43 can protrude upward from the adhesive material layer 44.
[0027]
The base 41 is made of the same material as the base (21) of the first embodiment described with reference to FIGS. 1 and 2, and the upper surface 42 is more than the wafer W to be placed. It has a sufficiently wide area.
Further, the support tool 43 is composed of, for example, three pins, and is configured to support the wafer W on the surface constituted by each pin. In the base 41 and the adhesive material layer 44, a hole pattern 45 is formed in the protruding portion of the support 43 so that the support 43 can protrude from the upper surface 42 of the base 41.
[0028]
The adhesive material layer 44 has a sufficiently larger area than the wafer to be placed. The adhesive material layer 44 has such adhesiveness that the adhesive material does not adhere to the back surface of the wafer W, and is made of, for example, an acrylic resin or a polyethylene resin. The adhesive material layer 44 is provided on the upper surface of the base film 44b provided with the adhesive layer 44a on the back side so that the adhesive material layer 44 can be easily replaced. It is assumed that it is provided on the base 41 by being adhered to the base 41. In this case, the adhesive force of the adhesive layer 44 a is stronger than the adhesive material layer 44. However, the adhesive material layer 44 may be provided directly on the base 41 when it is not necessary to consider the time and effort for replacement.
[0029]
According to the wafer mounting table 4 configured as described above, the adhesive material layer 44 is provided on the base 41, and the support tool 43 is provided so as to protrude from the adhesive material layer 44. The wafer W is placed on the adhesive material layer 44 in a state where it is buried in the layer 44, and the wafer W is supported by the support tool 43 when the support tool 43 is protruded from the adhesive material layer 44.
[0030]
FIG. 7 is a cross-sectional process diagram illustrating a wafer back surface processing method using the wafer mounting table 4 of the third embodiment. In the following, an embodiment of a wafer back surface processing method will be described. First, as shown in FIG. 7A, the support tool 43 of the wafer mounting table 4 is raised and protruded from the adhesive material layer 44. Next, the wafer W is supported on the support 43 with the back surface of the wafer W opposed to the adhesive material layer 44.
[0031]
At this time, the transfer arm 5 for transferring the wafer W is used to transfer the wafer W placed on the transfer arm 5 onto the support 43 and place it thereon. An adhesive material layer 51 is provided on the upper surface of the transfer arm 5. The adhesive material layer 51 is the same as the adhesive material layer 44 of the wafer mounting table 4.
[0032]
Next, as shown in FIG. 7 (2), after the transfer arm (5) is extracted from under the wafer W, the support tool 43 is lowered and buried in the adhesive material layer 44. As a result, the wafer W is placed on the adhesive material layer 44, and the back surface of the wafer W is adhered to the adhesive material layer 44.
[0033]
Thereafter, as shown in FIG. 7 (3), the support tool 43 is raised, and the wafer W placed on the adhesive material layer 44 is supported on the support tool 43 from the adhesive material layer 44.
Thereafter, the wafer back surface is processed by repeatedly lowering and raising the support tool 43 as necessary.
[0034]
Then, after the processing of the wafer back surface is completed, the transfer arm (5) is inserted under the wafer W supported by the support tool 43, and the transfer arm (5) moves the wafer W onto the wafer mounting table of the manufacturing apparatus of the next process. Transport to.
[0035]
According to the processing method for the back surface of the wafer, when the wafer W is placed on the adhesive material layer 44 as shown in FIG. The foreign material a can be adhered to the adhesive material layer 44. Then, after placing the wafer W on the adhesive material layer 44, the support tool 43 is raised to support the wafer W on the support tool 43, so that the foreign material a is adhered to the adhesive material layer 44. The foreign material a can be removed from the back surface of the wafer W while remaining on the adhesive material layer 44 while being adhered to the surface of the wafer W.
[0036]
Therefore, in the next manufacturing apparatus in which the wafer W is transferred, the wafer W can be processed without considering the influence of the foreign matter a attached to the back surface of the wafer W. Further, it is possible to prevent the wafer W transfer system and the manufacturing apparatus used in the next process from being contaminated by the foreign matter a.
[0037]
In addition, since the adhesive material layer 51 is also provided on the transfer arm 5, the foreign substance a on the back surface of the wafer W can be removed also by the transfer arm 5.
[0038]
【The invention's effect】
As described above , according to the wafer mounting table of the present invention, the surface on which the wafer is fixedly mounted is made of low-viscosity resin, so that the pressure caused by foreign matter sandwiched between the wafer mounting table and the wafer is reduced. By absorbing with the low viscosity resin, it becomes possible to keep the surface side of the wafer flat. For this reason, for example, in an exposure apparatus equipped with this wafer mounting table, it becomes possible to perform exposure while maintaining a good focus on the entire surface of the wafer, and in a spin coating apparatus, a coating film having a uniform film thickness is formed on the entire surface of the wafer. It becomes possible to obtain.
[0039]
Further, the wafer mounting table of the present invention is a wafer mounting table having a wafer support provided so as to be protruded from the base table, and an adhesive material layer is provided on the base table, whereby an adhesive material is provided. It is possible to freely peel and peel the wafer back surface from the layer. In the wafer back surface processing method according to claim 6, wherein the wafer mounting table is used, after the wafer is placed on the adhesive material layer, the support is raised to support the wafer on the support. It becomes possible to remove the foreign matter from the back side of the wafer by adhering the foreign matter attached to the back side of the wafer to the adhesive material layer. Therefore, in the next process, the wafer can be processed without considering the influence of foreign matter on the back surface of the wafer.
[Brief description of the drawings]
FIG. 1 is a top view of a wafer mounting table according to a first embodiment.
FIG. 2 is a cross-sectional view taken along the line AA ′ in FIG.
FIG. 3 is a perspective view of a wafer mounting table according to a second embodiment.
4 is a cross-sectional view taken along line AA ′ of FIG.
FIG. 5 is a perspective view of a wafer mounting table according to a third embodiment.
6 is a cross-sectional view taken along the line AA ′ of FIG.
FIG. 7 is a process diagram illustrating a wafer back surface processing method by a wafer mounting table according to a third embodiment;
FIG. 8 is a top view showing an example of a conventional wafer mounting table.
FIG. 9 is a cross-sectional view taken along the line AA ′ of FIG.
[Explanation of symbols]
2, 3, 4 Wafer mounting table 21, 31, 41 Base 22, 22, 42 Upper surface 23 Suction groove 24 Suction tube 25 Groove 26 Low viscosity resin 33 Fixing pin 34 Low viscosity resin layer 43 Support tool 44 Adhesive resin layer W Wafer

Claims (6)

In a wafer mounting table having a base and an adsorption groove provided on the upper surface side of the base and connected to the suction pipe,
A groove provided between the adsorption grooves on the upper surface side of the base, and a low-viscosity resin having adhesiveness filled in the groove;
Equipped with a,
A wafer mounting table, wherein a side wall composed of the base is provided between the suction groove and the groove . The wafer mounting table according to claim 1,
The low-viscosity resin includes a mixture of a gel-like resin and a hydrophobic resin. The wafer mounting table according to any one of claims 1 and 2,
The low-viscosity resin includes an acrylic resin or a polyethylene resin. An exposure apparatus comprising the wafer mounting table according to claim 1 . A spin coater comprising the wafer mounting table according to claim 1 . A step of mounting a wafer on the wafer mounting table according to claim 1 ;
And a step of removing the wafer from the wafer mounting table.

Images