JPH06103675B2 - Wafer center positioning method in two-division cutting of semiconductor wafer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a wafer center positioning method for two-division cutting of a semiconductor wafer.

More specifically, for example, as an intermediate step of manufacturing a substrate for discrete elements such as transistors and diodes, when a semiconductor wafer having diffusion layers on both sides is cut into two parts from the center of the thickness, the semiconductor wafer is supplied. The present invention relates to a method for accurately aligning the center of wafer transfer with a holding mechanism for receiving and holding the wafer from the supply mechanism, and ensuring proper centering.

[Prior Art] Conventionally, a method of holding and cutting a semiconductor wafer, particularly a wafer movement between a supply mechanism and a holding mechanism of a wafer cutting mechanism, has been proposed by the applicant in Japanese Patent Laid-Open No. 3-145726. There is.

This applicant's previous proposal is for an intermediate step of manufacturing a discrete device substrate, and is for cutting a semiconductor wafer sliced from an ingot and having impurities diffused on both sides into two parts from the center of the thickness width. is there. This cutting is performed by a cutting mechanism which holds a semiconductor wafer supplied by a supply mechanism having a suction function vertically in a holding mechanism which also has a suction function, and which has an inner peripheral rotary cutting blade that rotates at high speed.

[Problems to be Solved by the Invention] In the above-mentioned prior proposal of the applicant, there is an error in taking out a semiconductor wafer by a supply mechanism from a supply unit of a supply cassette in which an unprocessed (before cutting) semiconductor wafer is stored. Accumulation of movement error to the holding mechanism by the supply mechanism, etc., and when the semiconductor wafer is transferred from the supply mechanism to the holding mechanism, a center misalignment occurs between the center of the semiconductor wafer and the center of the holding surface of the holding mechanism. In FIG. 1, the wafer delivered by the wafer supply mechanism is the center of rotation C of the cutting blade in the figure.
In order to obtain good cutting efficiency from the position of 0 to the position of 0, it may touch the inner edge of the inner edge when approaching at high speed (several times of the normal cutting speed), and may cause the inner edge of the wafer to be broken. Therefore, the margin must be set excessively at the starting position (b in the figure) of the cutting stroke of the semiconductor wafer, and there is a point to be improved in terms of good cutting efficiency.

Further, when the semiconductor wafer is transferred from the supply mechanism to the holding mechanism, the operation of the suction function of the supply mechanism and the holding mechanism is switched, but if the operation switching is not coordinated precisely,
In a so-called horizontal slicer device that holds a semiconductor wafer vertically to a holding mechanism, the semiconductor wafer has a point to be improved in that the semiconductor wafer may be dropped and damaged.

The present invention has been made in consideration of such points to be improved, and provides a method for accurately centering and reliably holding a semiconductor wafer when the semiconductor wafer is transferred from a supply mechanism to a holding mechanism. The challenge is to provide.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the wafer center positioning method according to the present invention employs the following means.

That is, in claim 1, in the two-divided cutting of the semiconductor wafer in which the semiconductor wafer delivered from the supply mechanism is vertically held by the holding mechanism, and the wafer is cut into two from the center of the thickness width by the cutting mechanism, Provided below the holding mechanism is a centering mechanism having at least two tip members arranged in a direction orthogonal to a vertical holding surface of the holding mechanism and capable of advancing and retracting in the arranging direction. When the semiconductor wafer is delivered, the semiconductor wafer is detached from the suction plate and is dropped and brought into contact with the tip member protruding from the centering mechanism to perform center positioning operation, and the positioning operation is performed on the tip member. It is characterized in that the completed semiconductor wafer is pushed and held on the holding surface of the holding mechanism, and the tip end member of the centering mechanism is retracted to avoid the cutting action surface of the cutting blade.

According to a second aspect of the present invention, in the method of centering a wafer according to the first aspect, the center line of the thickness of the wafer does not change in the thickness direction by forming impurity diffusion layers on both sides of the semiconductor wafer. It is characterized by having material properties symmetrical with respect to.

[Operation] According to the above-mentioned means, according to the first aspect, the semiconductor wafer is dropped by its own weight and brought into contact with the projecting tip member of the centering mechanism to correct the center misalignment in an extremely simplified form. The centering (centering) operation is performed, and the semiconductor wafer delivery auxiliary operation is performed in which the centered semiconductor wafer is pushed from the suction plate of the supply mechanism to the holding surface of the holding mechanism and gently to the holding surface. As a result, the semiconductor wafer is prevented from falling off and is reliably delivered and held from the supply mechanism to the holding mechanism. Since the tip member of the holding mechanism can avoid the cutting mechanism, the equipment of the centering mechanism does not hinder the operation of each part during the cutting.

Further, the second aspect is suitable for a semiconductor wafer or the like in which impurities are diffused on both sides.

[Embodiment] An embodiment of a method for centering a semiconductor wafer according to the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 and 2, this embodiment is an example of a horizontal type embodiment apparatus having a supply mechanism 1 and a holding mechanism 2 having a suction function by vacuum.
The y and z directions are shown.

The supply mechanism 1 of this embodiment has an adsorption disk 12 connected to a vacuum pump (not shown) and formed into a circular suction disk shape with an elastic material such as a rubber material capable of blowing air at appropriate times. is doing.

The supply mechanism 1 is capable of adsorbing or detaching one side of an unprocessed semiconductor wafer W on an adsorption disk 12 by vacuum adsorption by vacuum or air blowing, and an arm 11 connected to the adsorption disk 12 and a movement drive unit. The unprocessed semiconductor wafer W is taken out from a supply unit such as a supply cassette (not shown) and moved to the holding mechanism 2.

The holding mechanism 2 of this embodiment example has a flat holding surface made of porous ceramics or the like, and has a holding plate 22 attached to one side of a chamber 21 connected to a vacuum pump (not shown). The holding mechanism 2 is capable of sucking and holding one side of the unprocessed semiconductor wafer W on the holding plate 22 by suction and release of the vacuum by intermittent holding of the vacuum. And supply mechanism 1
The delivery of the wafer to the holding mechanism 2 is performed on the center of the rotation axis of the cutting blade, and then the distance b to the cutting blade edge is rapidly approached to improve the cutting efficiency. A position feeding mechanism for indexing the central portion of the thickness width of the wafer W to the cutting action surface of the cutting blade 3'of the cutting mechanism 3 (y direction), and a movement for cutting the held semiconductor wafer W (x
It is cut into two parts by the cutting feed mechanism that performs the direction.

The cutting mechanism 3 has an inner peripheral cutting blade 3 ′ that rotates at high speed.

The supply mechanism 1, the holding mechanism 2, and the cutting mechanism 3 have the same basic structure as the previous proposal of the applicant of the present invention, but the holding mechanism 2 is further provided with a centering mechanism 4 on the lower side thereof, which is accurate. The feature of the present invention is to enable easy centering.

The centering mechanism 4 is made of tetrafluoroethylene resin or the like and has an L-shaped cross section, and is arranged in a direction orthogonal to the holding plane about the center O of the holding surface of the holding plate 22 of the holding mechanism 2. It is composed of two tip members 41 and a drive unit 42 supported by the chamber 21 so that the tip members 41 can be moved in the arrangement direction (direction orthogonal to the holding surface) by an air cylinder or the like. Therefore, the centering mechanism 4 can be easily incorporated into the conventional device configuration.

Further, the semiconductor wafer W to be cut in such an example of the embodiment apparatus is not limited to the one for manufacturing a discrete element substrate in which impurities are diffused on both sides, and SiO _{2 can be formed on} both sides of a defect-free wafer such as an SO 1 substrate. It can also be used to cut a composite wafer that is adhered to two supporting substrates via a film.

Note that FIG. 1 shows a semiconductor wafer W having a cutting end W to which a reinforcing contact plate W'is attached, which does not interfere with the centering mechanism.

The operation of the present invention will be described with reference to FIG. 3. The drive unit 42 of the centering mechanism 4 is controlled to move the tip end member 41 to the forward position where it projects from the holding plate 22, and the suction mechanism of the supply mechanism 1 is sucked. While the unprocessed semiconductor wafer W is adsorbed on the board 12, it is lowered and supplied to the front surface of the holding board 22 (see FIG. 3, A ₁ ,
A ₂ ).

The descending semiconductor wafer W is stopped at a position where it reaches a certain distance d on the tip member 41, and the suction plate 12 is brought closer to the holding plate 22 by a short stroke cylinder or the like (not shown), and at that position. The vacuum suction of the suction disk 12 is stopped and the reverse air blowing operation is activated to drop the semiconductor wafer W onto the tip member 41, whereby the center between the center of the semiconductor wafer W and the center of the holding surface of the holding disk 22. Matching is done (FIG. 3B).

(Because the falling area d of the semiconductor wafer W is small (several mm), the wafer W is not damaged.) The semiconductor wafer W dropped on the tip member 41 is the suction plate.
With the continuous air blowing operation of 12, the tip member 41 is gently pushed toward the holding plate 22 with the tip member 41 as a guide, and the semiconductor wafer W is held on the holding plate 22 while the alignment of the two is maintained by the vacuum suction action of the holding plate 22 which is activated at the same time. It is adsorbed and held by 22 (Fig. 3C).

Then, in preparation for the start of the cutting process, the tip member 41 is driven by
It is retracted by 42, and the suction plate 12 also moves upward (FIG. 3D).

The holding mechanism 2 that sucks and holds the semiconductor wafer W is moved leftward in the drawing by a position feeding mechanism (not shown) so that the cutting blade 3'is positioned at the center of the thickness width of the wafer W ( A cutting process is started by driving (not shown), and the holding mechanism 2 is retracted at the end of the process, and after the processed semiconductor wafer divided into two parts is collected from the holding plate 22, A ₁ , FIG. The operation of supplying a new unprocessed wafer shown in A ₂ is started, and the operation described above is repeated.

[Advantages of the Invention] As described above, according to the present invention, in claim 1, while performing the centering operation for correcting the center misalignment by the centering mechanism,
The centering mechanism, the supply mechanism, and the holding mechanism regulate the falling distance of the semiconductor wafer and the handling of the semiconductor wafer becomes soft, so that the semiconductor wafer is prevented from being damaged, and
The semiconductor wafer can be delivered from the supply mechanism to the holding mechanism accurately and reliably. Also, due to this effect,
The effect of improving the cutting efficiency of the semiconductor wafer occurs.

Further, there is an effect that the structure of the centering mechanism can be simplified.

Further, in claim 2, there is an effect that it can effectively contribute to the manufacture of the discrete element substrate.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a wafer center positioning method in a semiconductor wafer divided into two pieces according to the present invention.
The figure is a side view of FIG. ₁ , FIG. 3 A ₁ , B, C, D are side views for explaining the operation of the present invention, and FIG. 3 A ₂ is a front view of FIG. 3 A ₁ . DESCRIPTION OF SYMBOLS 1 ... Supply mechanism, 2 ... Holding mechanism 3 ... Cutting mechanism, 4 ... Centering mechanism W ... Semiconductor wafer

Claims (2)

[Claims] 1. A semiconductor wafer is passed from a supply mechanism to a holding mechanism, one side of the wafer is held vertically by the holding mechanism, and the wafer is moved from the center of the width to a width of 2 by a cutting mechanism having an inner peripheral rotary cutting blade. In the method of centrally positioning a wafer of a holding mechanism when cutting into divided pieces, at least two pieces which are arranged below the holding mechanism in a direction orthogonal to a vertical holding surface of the holding mechanism and which can move forward and backward in the arrangement direction. A centering mechanism having a tip member is provided, and when the supply mechanism delivers the semiconductor wafer to the holding mechanism, the semiconductor wafer is detached from the suction plate and dropped onto the projecting tip member of the centering mechanism. By doing so, the center of the semiconductor wafer and the center of the holding surface of the holding mechanism are aligned with each other, and the wafer is pushed to the holding surface of the holding mechanism, and when the holding mechanism holds the wafer, the centering is performed. Retracting the tip member of the structure, thereby avoiding the cutting action face of the cutting blade of the cutting mechanism, the center positioning method of a wafer, characterized in that. 2. The center of a wafer according to claim 1, wherein the semiconductor wafer has a material characteristic symmetrical with respect to a center line of the thickness of the wafer, which is not accompanied by a material change in the thickness direction. Positioning method.