JPH0469813B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for forming a thin resin film layer interposed between a semiconductor wafer and a plate when a semiconductor wafer is held on a plate of a polishing device and mirror polished. (Prior Art) In the process of mirror polishing a semiconductor wafer, the semiconductor wafer is mounted (held) on a plate of a polishing device, and there are two types of mounting methods: wax method and waxless method. be. The above-mentioned wax method has the advantage of obtaining semiconductor wafers with good flatness, while the waxless method does not require a wax application step and the semiconductor wafer surface can be easily cleaned after polishing, resulting in improved productivity and cost. It has the advantage of being advantageous in terms of However, on the other hand, the waxless method has the disadvantage that the flatness of the semiconductor wafer is poor and the quality of the back surface of the semiconductor wafer is poor. This waxless method is further classified into a vacuum suction method, a template method, a method using frictional force, and a flex mounting method depending on the method of mounting the semiconductor wafer on the plate. By the way, when using the vacuum suction method mentioned above among the waxless methods, a mounting material is interposed between the plate of the polishing device and the semiconductor wafer, and the semiconductor wafer is made of a hard material (stainless steel (SUS), ceramic, etc.). This prevents the back surface of the molded plate from being scratched or contaminated by direct contact. Therefore, for the purpose of obtaining semiconductor wafers with high flatness, the above-mentioned mounting material should have the following properties:
Even during polishing, where repeated loads and uneven polishing loads are applied, and in contact with abrasives, elasticity and thickness must be uniform over the entire surface.As the mounting material, for example, polyurethane foam can be used. layers have traditionally been used. However, when a semiconductor wafer is adsorbed using the conventional mounting material described above, the degree of decompression differs between the center and the outer periphery of the semiconductor wafer, resulting in uneven deformation of the mounting material and high flat surfaces. Not only is it not possible to obtain semiconductor wafers of high quality, but repeated use of the mounting material also causes problems such as permanent deformation of the mounting material. Therefore, a method was proposed in which an elastic film such as an organic resin film was formed on the surface of the plate and this elastic film was used as a mounting material (Japanese Patent Application Laid-Open No. 155494/1983).
(see publication). (Problems to be Solved by the Invention) However, in the above method, as shown in FIG.
After the elastic film 109 is formed on the surface, the plate 1
As shown in FIG. 6, the part of the resin 108 that has entered the through hole 104 drilled in the plate 103 and hardened is removed from the back side of the plate 103 using a tool T such as a drill. The work of perforating the membrane 109 was necessary, and many steps were required. Also, during the work, the surface of the plate 103 is exposed to the tool T.
In particular, if the plate 103 is made of metal, burrs may occur, and if it is made of a brittle material such as ceramic, chipping may occur. Furthermore, the through holes drilled in the plate 103 have a small diameter (for example, several 100 μm).
If this is the case, or if the plate 103 is thick, there is no commercially available tool that can handle this problem, and there is also the problem that drilling cannot actually be performed. The present invention has been made in view of the above-mentioned problems, and its purpose is to reduce the number of holes without damaging the plate, etc., regardless of the thickness of the plate and the diameter of the through hole drilled in the plate. It is an object of the present invention to provide a method for forming a resin thin film layer for semiconductor wafer mounting, which can efficiently obtain a desired resin thin film layer in a process. (Means for Solving the Problems) In order to achieve the above object, the present invention provides a surface of a plate formed with a large number of minute through holes, and injects compressed gas into the minute through holes from the back side of the plate. It is characterized in that a resin thin film layer is formed by coating with a resin coating agent while passing through, and the surface of the resin thin film layer is lapped. (Function) When coating the surface of the plate with a resin coating agent, the resin coating agent does not enter the minute through holes of the plate due to the compressed gas ejected from the minute through holes drilled in the plate. Instead of flowing in, the resin coating agent hardens and the resin thin film layer formed on the plate surface has a large number of micro holes that communicate with the micro through holes of the plate, which requires a drill that was previously required. This eliminates the need for drilling into the resin thin film layer using tools such as tools, etc., and the desired result can be efficiently achieved with fewer steps without damaging the plate, etc., regardless of the thickness of the plate or the diameter of the through hole drilled in the plate. A resin thin film layer can be obtained. (Example) An example of the present invention will be described below based on the accompanying drawings. FIG. 1 is a schematic configuration diagram of an apparatus for carrying out the method of the present invention. In the figure, 1 is an air chamber, and a part of the upper surface of the air chamber 1 is opened in a circular shape. A disk-shaped plate 3 is placed horizontally on the plate 1 with its surface 3a facing upward, with an elastic seal ring 2 interposed therebetween. The plate 3 is made of a highly rigid material such as stainless steel (SUS) or ceramic, and has a large number of minute through holes 4 bored therein. Further, the air chamber 1 is connected to an air compressor 6 via a pipe 5 led out from a side wall thereof, and a flow rate regulating valve 7 is interposed in the middle of the pipe 5. The method of the present invention is carried out in the following steps using the apparatus described above. That is, first, the air compressor 6 is driven to produce compressed air a.
is supplied into the air chamber 1 through the pipe 5. Incidentally, the amount of compressed air a supplied to the air chamber 1 is controlled by adjusting the opening degree of the flow rate regulating valve 7 interposed in the middle of the pipe 5. The compressed air a that is continuously supplied into the air chamber 1 passes through the minute through holes 4 from the back surface 3b side of the plate 3 placed on the air chamber 1.
In this state, a resin coating agent 8 such as an epoxy resin adhesive is uniformly applied onto the surface 3a of the plate 3 as shown in FIG. 2. At this time, the resin coating agent 8 does not flow into the micro through holes 4 due to the flow of compressed air a jetting upward from the large number of micro through holes 4 formed in the plate 3. When the resin coating agent 8 applied on the plate surface 3a is cured to a certain extent, a resin thin film layer 9 is formed on the plate surface 3a by cutting off the supply of compressed air a to the air chamber 1. However, as mentioned above, when applying the resin coating agent 8, the resin coating agent 8 does not flow into the minute through holes 4 of the plate 3, so the resin thin film layer 9 is coated with the resin coating agent 8 shown in FIG. Plate 3 as shown
A large number of micro holes 10... communicate with the micro through holes 4...
will be drilled. As described above, if the resin coating agent 8 is applied while blowing compressed air a from the minute through holes 4 of the plate 3, the resin coating agent 8 will harden and a thin resin film will be formed on the surface 3a of the plate 3. At the time when the resin thin film layer 9 is formed, the plate 3 is attached to the resin thin film layer 9.
Since the micro holes 10 communicating with the micro through holes 4 are drilled, it is no longer necessary to drill into the resin thin film layer 9 using a tool such as a drill, which was required in the past, and the plate 3 etc. are not damaged. Furthermore, plate 3
The desired resin thin plate layer 9 can be obtained with fewer steps without causing burrs or chipping.
In addition, since the flow of compressed air a is used to perforate the resin thin film layer 9, the resin is processed regardless of the thickness t of the plate 3, the diameter d of the through holes 4 formed in the plate 3, and the cross-sectional shape. The thin film layer 9 can be easily perforated. In this way, a resin thin film layer 9 is formed on the surface 3a of the plate 3, and the surface of this resin thin film layer 9 is lapped in the next step, so that the surface is finished into a surface with high flatness accuracy. The resin thin film layer 9 whose surface has been lapped functions as the above-mentioned mounting material for holding the semiconductor wafer by suction when the semiconductor wafer is mirror-polished by the polishing device. Incidentally, in the lapping treatment of the surface of the resin thin film layer 9, soft particles such as silica having a minute particle size are used as a lapping agent. By the way, in the above embodiments, an epoxy resin adhesive, which is a thermosetting adhesive, was used as the resin coating agent 8. They are shown in Table 1 and Table 2, respectively.

【table】

【table】

[Table] As the thermosetting adhesive, in addition to the epoxy resin adhesive, phenol resin, urea resin adhesive, etc. can be used.Furthermore, as the resin coating agent 8, thermosetting resin adhesive can be used. In addition to the adhesive, thermoplastic resin adhesives such as polyethylene, vinyl chloride resin, and acrylic resin adhesives can also be used. Furthermore, in the above embodiments, air was particularly used as the compressed gas, but in addition to air, an inert gas such as nitrogen may also be used. Next, a specific example of a polishing apparatus using the resin thin film layer 9 as a mounting material for holding a semiconductor wafer will be described with reference to FIG. That is, FIG. 4 is a longitudinal cross-sectional view of the polishing device, and in the same figure, reference numeral 11 is a disc-shaped surface plate, and the surface plate 11 is driven to rotate around its central axis by a drive device (not shown). An abrasive cloth 12 having appropriate elasticity is attached to the upper surface thereof. or,
A shaft 13 is vertically installed above the outer circumference of the surface plate 11, and the plate 3 is attached to the lower end of the shaft 13 via a spherical bearing 14 so as to be tiltable. The resin thin film layer 9, which is a mounting material, is formed on the surface (lower surface in the illustrated example) 3a of the plate 3. The plate 3 is rotatably supported by a shaft 13 via a ball bearing 15 that rotatably supports a spherical bearing 14. As described above, this plate 3 is provided with a large number of minute through holes 4. Further, the shaft 13 is hollow, and a hole 13a penetrated through the center of the shaft 13 is communicated with a vacuum pump 16 as shown in the figure, and an end of the hole 13a is connected to the spherical bearing 14. It opens into a space S surrounded by the plate 3. On the other hand, a plurality of annular grooves 17 communicating with the space S are concentrically formed on the lower surface of the spherical bearing 14. A thin plate-shaped semiconductor wafer W, which is an object to be polished, is attracted to the lower surface of the plate 3 with a resin thin film layer 9 in between, and the semiconductor wafer W is held in a predetermined manner. It is pressed onto the polishing cloth 12 by force. Next, the polishing operation of the semiconductor wafer W using this polishing apparatus will be explained. The thin semiconductor wafer W has minute through holes 4..., 10 bored in the plate 3 and the resin thin film layer 9.
..., the space S, the resin thin film layer 9 due to the negative pressure drawn by the vacuum pump 16 through the hole 13a in the shaft 13.
It is held by suction on the bottom surface of. On the other hand, the surface plate 11 is rotated horizontally around its central axis at a constant speed by a drive mechanism (not shown), and the semiconductor wafer W held on the resin thin film layer 9 is placed on the surface plate 11. Affixed abrasive cloth 12
is pressed against the upper surface of the holder with a predetermined force. Then, relative slippage occurs between the semiconductor wafer W and the abrasive cloth 12, and due to this slippage, the semiconductor wafer W is supplied with abrasive from a nozzle (not shown) while the abrasive cloth 12
Mirror polished by 2. In the above, the semiconductor wafer W is held by the non-foaming resin thin film layer 9 with high rigidity, and the surface of the resin thin film layer 9 is lapped to maintain high flatness accuracy, so that the mirror polishing is performed. The degree of flatness of the surface of the semiconductor wafer W after this is kept extremely high. (Effects of the Invention) As is clear from the above description, according to the present invention, compressed gas is allowed to pass from the back side of the plate to the micro through holes on the surface of the plate formed with a large number of micro through holes. At the same time, since the resin coating agent is coated to form a resin thin film layer and the surface of the resin thin film layer is lapped, when the resin coating agent is coated on the plate surface, this resin coating agent is Because of the compressed gas ejected from the minute through holes drilled in the plate, it does not flow into the minute through holes of the plate, and the resin coating agent hardens and forms a thin resin film layer on the plate surface. A large number of micro-holes communicating with the micro-through holes of The effect is that a desired resin thin film layer can be efficiently obtained with a small number of steps, regardless of the diameter and cross-sectional shape of the minute through-holes, and without damaging the plate or the like.

[Brief explanation of the drawing]

Figure 1 is a schematic configuration diagram of an apparatus for carrying out the method of the present invention, Figure 2 is a cross-sectional view showing the state in which a resin coating agent is applied to the surface of a plate, and Figure 3 is a thin resin film layer formed on the surface. FIG. 4 is a longitudinal sectional view of the polishing device, and FIGS. 5 and 6 are sectional views showing conventional drilling operations. 3...Plate, 4...Minute through hole, 8...Resin coating agent, 9...Resin thin film layer, 10...
...Micropore, a...Compressed air, W...Semiconductor wafer.

Claims (1)

[Scope of Claims] 1. A resin coating agent is coated on the surface of a plate having a large number of minute through-holes while allowing compressed gas to pass through the minute through-holes from the back side of the plate. 1. A method for forming a resin thin film layer for semiconductor wafer mounting, comprising forming a thin film layer and subjecting the surface of the resin thin film layer to a lapping treatment. 2. The method of forming a resin thin film layer for semiconductor wafer mounting according to claim 1, wherein the resin coating agent is a thermoplastic or thermosetting resin adhesive. 3. Claim 2, wherein the thermosetting resin adhesive is an epoxy resin adhesive.
A method for forming a resin film layer for semiconductor wafer mounting as described in 1.