JPH0525243Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) This invention is used to cut a semiconductor wafer into two parts from the center of a thick width to manufacture discrete elements such as transistors. The present invention relates to a holding device that attracts and holds a cut semiconductor wafer at the latest immediately before cutting is completed.

(Prior Art) The applicant has already developed a method in which one side of a semiconductor wafer, on which an impurity diffusion layer has been formed, is completely suctioned and held by a suction cup, and this semiconductor wafer is cut into a thickness using an internal diamond cutter or the like. Holding of a cut semiconductor wafer in which the cut semiconductor wafer on the side opposite to the side firmly held by a suction cup is collected by suction before the cutting is completed during the cutting process of cutting the cut semiconductor wafer into two parts from the center of the width. A method and apparatus have been proposed (Japanese Patent Application Laid-open No. 1072/1983).

Separately, there is a device for suction-holding a cut semiconductor wafer, which suction-holds the wafer before it is cut from an end face of a silicon semiconductor ingot when the wafer is cut out from the ingot.

Each of the devices described above is equipped with a suction cup body made of metal or ceramics, and the suction surface of this suction cup body is formed in a substantially flat shape.

Also, the curvature of the suction surface can be changed in some cases;
The shape was symmetrical with respect to the vertical line at the center of the suction surface as the axis of symmetry.

In particular, when cutting semiconductor wafers such as those mentioned above,
When a semiconductor wafer with impurities diffused on both sides is divided into two parts from the center of its thickness, cutting begins along the center of the wafer, mainly because the properties of the central layer of the wafer are different from those of the layers on both sides. As the cutting process progresses, the cut semiconductor wafer on the side opposite to the side held by the suction cup gradually begins to warp outward.

Then, from the time when the surface of the cut semiconductor wafer in this state is suctioned and held by the flat suction cup as described above, a load force is applied to the wafer to forcibly correct the warp; Due to the difference in vibration systems between the holding device that holds the cut semiconductor wafer before cutting is completed and the holding device that firmly holds one side during cutting, cracks occur on the wafer periphery where it intersects with the cutter. There was something I ended up doing.

(Problem to be Solved by the Invention) The problem to be solved by the invention is to suction and hold the cut semiconductor wafer before the cutting is completed without applying an unreasonable load force to the cut semiconductor wafer, which warps as described above. At the same time, it is an object of the present invention to provide an adsorption/holding structure that absorbs and holds the vibration difference between the semiconductor wafer and the wafer, thereby preventing damage to the peripheral edge of the cut semiconductor wafer during the cutting operation.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the cutting semiconductor wafer holding device of the present invention has a suction cup made of rubber or soft synthetic resin that sticks to the surface of the cut semiconductor wafer at the tip of the arm body. A plurality of suction cup bodies are disposed, these suction cup bodies are connected to a suction means, and the amount of protrusion of each suction cup body with respect to the wafer surface can be adjusted and supported.

Further, a structure is adopted in which the suction opening edges of each of the plurality of suction cups are formed so as to be tilted so as to face each other in accordance with the warped curved surface that occurs when the cut semiconductor wafer is cut.

(Function) According to the above means, the plurality of suction cups provided at the tips of the arms are respectively attracted to the plurality of parts on the surface of the cut semiconductor wafer by suction by the suction means.

In parallel with the progress of cutting, the cut semiconductor wafer gradually warps outward to a large extent.

On the other hand, the amount of protrusion of each suction cup body is adjusted in accordance with the amount of warp deformation of each suction point on the wafer surface, which warps and deforms as described above at the time of suction action. As a result, each suction cup is aligned with and adsorbs the warped wafer surface, and the cut semiconductor wafer is held in the warped state and an unreasonable load force is applied to the wafer. is prevented.

In addition, the vibration difference generated between the wafer and the holding device, which is directly subjected to cutting vibration by the cutter, is absorbed by the elastic deformation of the suction cup.

By slanting the suction mouth edge of each suction cup body in accordance with the expected warping angle of the cut semiconductor wafer, each suction cup body can be positioned precisely at each suction site on the surface of the cut semiconductor wafer where the mouth edge is warped. It adsorbs in the opposite state.

(Effects of the invention) As described above, the holding device for a cut semiconductor wafer of the present invention is provided with a plurality of suction cups made of rubber or soft synthetic resin, and the amount of protrusion of the suction cups from the surface of the cut semiconductor wafer can be adjusted. It is mounted and supported. Therefore, the amount of protrusion of each suction cup body is adjusted in accordance with the amount of warpage of the suction part on the surface of the cut semiconductor wafer, which is warped and deformed at the time of suction action during cutting, and the cutting process is performed by adjusting the amount of protrusion of each suction cup body. By creating a suction surface that matches the surface of the semiconductor wafer, each suction cup can be attached without any steps to match the surface of the cut semiconductor wafer, which undergoes different warping deformation depending on the lot in the pre-diffusion process of the raw material wafer. It is possible to suction and hold the cut semiconductor wafer in a warped and deformed state without applying an unreasonable load.

In addition, the vibration difference between the cut semiconductor wafer and the holding device, which is directly affected by the cutting vibration caused by the cutter during cutting, can be absorbed by the elasticity of each suction cup. Damage occurring at the periphery can be effectively prevented.

Furthermore, since the shape of the suction mouth edge of each suction cup body is inclined according to the warp angle that occurs when the cut semiconductor wafer is cut, the suction mouth edge of each suction cup body can be adjusted to each suction area on the surface of the cut semiconductor wafer. Since the wafer can be suctioned while directly facing the wafer, there is little deformation of the suction body in the suction state, and the suction by the suction cup can be performed reliably, and the load force applied to the wafer can be reduced.

(Example) An example of the present invention will be described below with reference to the drawings. The semiconductor wafer W is made of a disc-shaped silicon single crystal, etc., and has an impurity undiffused layer in the center where impurities are not diffused. Impurity diffusion layers in which impurities are diffused are formed on both sides. FIG. 4 is an exaggerated view of the state in which the semiconductor wafer W as described above is being cut into two parts from the center of its thickness by the inner cutter C. Since the properties of the layer and the layer at the center of the wafer are different, the curve begins to warp outward from the start of cutting, and the amount of warp B reaches the mm level just before the end of cutting.

The reinforcing material D formed on the lower periphery of the semiconductor wafer W is an example of the purpose of preventing the lower periphery of the wafer, which is the end of cutting, from being damaged. It is formed by filling and hardening.

When the semiconductor wafer W is actually cut into two parts, substantially the entire surface of one side of the semiconductor wafer W is strongly sucked and held by the suction cup 7 made of porous ceramics or the like, so that the warpage deformation b of the semiconductor wafer W described above is avoided. This occurs only on the cut semiconductor wafer W'' on the side opposite to the cut semiconductor wafer W' on the side held by the suction cup 7 (FIG. 1).

The holding device A holds the cut semiconductor wafer W'' which is warped as described above by suction before the cutting is finished.
After cutting, the suction cup 2 is moved and delivered to a collection device (not shown), and a plurality of suction cup bodies 2, three in this embodiment, are attached to the tip of the arm body 1 that communicates with the suction device (not shown). is provided.

The arm body 1 is formed by connecting a hollow Y-shaped tube 1b that branches into a Y-shape to the tip of a base tube 1a that communicates with a suction device. The Y-shaped tube 1b is configured to have an internal space as a ventilation path 1b' by closing the ends which branch into two upwards. Then, the suction cup bodies 2 are attached to one side of the three points, the two tip ends and the base, respectively, facing one side, and these suction cup bodies 2 are attached to the Y-shaped pipe 1.
The suction cup 2 is arranged on an arc E centering on the branch point b, and the suction surface of each suction cup 2 can be raised or lowered from the same plane to adjust the protrusion height.

As shown in FIG. 3, the suction cup body 2 is made of rubber or soft synthetic resin, and has a dish-shaped part 2a that is fitted and fixed to the outer periphery of the tip of the hollow support shaft 4, and a part that extends along the outer periphery of the dish-shaped part. It is composed of a suction port edge 2b that protrudes,
The suction opening edge 2b is formed to be inclined in accordance with the warp angle of the cut semiconductor wafer W'' that is suctioned by each suction cup body 2.

Therefore, the suction opening edges 2b of the upper two suction cup bodies 2
The angle of inclination is relatively large, and the angle of inclination of the lower suction cup 2 is made small (see d in Fig. 3). As a result, each suction cup body 2 comes to be attracted to the suction surface of the warped and deformed cut semiconductor wafer W'' surface approximately directly facing the suction surface. By protruding upward, reliable adhesion can be obtained and vibration absorption properties can also be improved.

The support shaft 4 of each suction cup body 2 is the Y-shaped tube 1b of the arm body 1, respectively.
A fitting hole 6 for a boss member 6 that is screwed and fixed to the outer periphery.
It is mounted and supported by slidingly fitting into the inside of a.
Further, a coil spring 3 is elastically mounted between a flange 4a formed on the outer periphery of the support shaft 4 and an end face of the boss member 6, and a cap nut 5 fitted on the outside of the flange 4a is attached to the outer periphery of the boss member 6. By screwing into the
The support shaft 4 flange 4a of the suction cup body 2 is a coil spring 3
The stopping position of the suction cup 2 is reliably determined by being pressed against the inner end surface of the cap nut 5 by the elasticity of the suction cup 2, and the fixing nut 9 screwed onto the outer periphery of the support is brought into contact with the end surface of the cap nut 5. This prevents the suction cup body 2 from retreating.

Further, the protrusion amount F of each suction cup body 2 can be arbitrarily adjusted by loosening the fixing nut and rotating the cap nut 5. The amount of protrusion F of each suction cup 2 is made to move an appropriate amount in the sinking direction in accordance with the amount of warpage of each suction point on the surface of the cut semiconductor wafer W''. It is represented by

Each suction cup body 2 mounted and supported as described above has a support shaft 4
and a suction device (not shown) that communicates with the ventilation passage 1b' in the Y-shaped tube 1b via the passage 8 in the boss member 6.
Negative pressure is applied from the

The holding device A configured as described above supports the arm body 1 and each suction cup body 2 so as to move in parallel with the semiconductor wafer W held by the suction cup 7 in a general cutting method for moving a workpiece. When cutting the semiconductor wafer W into two parts from the top to the bottom with the center of the thickness width using the inner circumferential cutter C, some time before the wafer W is cut into two parts, the outside The surface of the cut semiconductor wafer W'', which is warped and deformed, is held by suction.

The three suction cup bodies 2 cut the semiconductor wafer so that the center of the arc E connecting them coincides with the center of the semiconductor wafer W, or is located slightly above the center.
At this time, the cut semiconductor wafer W'' is warped outward as shown in FIG. By adjusting the amount of protrusion F of the three suction cup bodies 2 in the direction of sinking relative to the lower suction cup body 2 based on the amount of warpage of the cut semiconductor wafer W'' at the suction point, the three suction cup bodies 2 can prevent warpage deformation. The cut semiconductor wafer W'' is placed without any step along the surface shape of the cut semiconductor wafer W'' which is curved. In addition, the suction mouth edge 2 of each suction cup body 2
b are inclined in accordance with the approximately average warp angle of the surface of the cut semiconductor wafer that they adsorb (d in Fig. 3), so that the suction opening of each suction cup 2 is attached to the wafer.
Since it is attracted directly to the surface of the wafer W'', it is possible to prevent the application of an unreasonable load force that would forcibly bend the wafer W'' back, unlike in the conventional case.

Furthermore, during cutting, the cut semiconductor wafer
The holding device for wafer W'' has a different vibration system from the suction cup 7 that holds the wafer W'', but this vibration difference can be absorbed by the elasticity of the suction cup body 2 made of rubber or soft synthetic resin, as described above. In combination with a comfortable holding state, it is possible to effectively prevent damage such as cracks occurring at the periphery of the cut semiconductor wafers W', W''.

The above-mentioned warping deformation b of the cut semiconductor wafer W'' changes in accordance with the processing form of the wafer W'' before cutting, and therefore, the protrusion amount F of each suction cup 2 depends on the suction effect for each processing lot, for example. The movement is adjusted in accordance with the degree of warp deformation at the time.

Furthermore, the number of suction cups installed is usually two or more,
Further, the arrangement thereof can be arbitrarily set depending on the target semiconductor wafer.

The holding device of the present invention can also be used to hold a wafer cut from a silicon semiconductor ingot.

In addition, as shown in the holding device A' shown in FIG. 5, the Y-shaped tube 1 of the arm body 1 is
It is also optional to provide the base tube 1a' to protrude from the center of b' to the back side.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway side view showing a state in which a cut semiconductor wafer is suctioned and held by a holding device embodying the present invention, Fig. 2 is a front view of the same device, and Fig. 3 is a support for a suction cup. A longitudinal sectional view showing the part, Figure 4 is 2
FIG. 5 is a side view showing a semiconductor wafer to be divided, and FIG. 5 is a partially cutaway side view showing a holding device in which the base tube of the arm extends rearward. In the figure, A...Holding device, C...Inner circumferential cutter, F...Protrusion amount, W...Semiconductor wafer, W''...
...cut semiconductor wafer, 1...arm body, 2...suction cup body.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A plurality of suction cup bodies made of rubber or soft synthetic resin are disposed at the tip of the arm body to attract the surface of the cut semiconductor wafer, and these suction cup bodies are connected to a suction means. Also, a holding device for a cut semiconductor wafer, in which the amount of protrusion of each suction cup relative to the wafer surface can be adjusted and supported. (2) The cut semiconductor according to claim 1, wherein the curved surface formed by the suction opening edge of each of the plurality of suction cup bodies as a whole is formed so as to face directly and be inclined in accordance with the warped curved surface that occurs when the cut semiconductor wafer is cut. Wafer holding device.