JPH0612770B2 - Semiconductor wafer cutting method - Google Patents

Description

The present invention relates to a semiconductor wafer cutting method.

More specifically, it relates to a method of cutting a semiconductor wafer for manufacturing a substrate for a discrete element such as a transistor, and to improvement of efficiency in the cutting process.

[Prior Art] Conventionally, the present applicant has previously proposed a semiconductor wafer cutting means for producing a substrate for a discrete element (Japanese Patent Laid-Open No. 3-145726).

That is, in a cutting means for cutting a semiconductor wafer having an impurity diffusion layer in which impurities are diffused on both sides from a substantially central portion of its thickness width, an object is to efficiently perform a cutting process without damaging the semiconductor wafer. Is.

Further, regarding the previous proposal of the present applicant, a method of forming a contact plate and the like is further described in JP-A-3-181131 and JP-A-3-58.
Proposed improvement of No. 807.

[Problems to be Solved by the Invention] In the above-mentioned prior proposal by the present applicant, since the semiconductor wafer is extremely thin, it is possible to prevent generation of minute cracks during cutting, particularly cracks at the end of cutting and to ensure accuracy. Therefore, there is a point to be improved in that the cutting speed cannot be increased as much as the slicing of a wafer from an ingot, and the cutting efficiency is not good.

The present invention has been made in consideration of such points to be improved and technical background, and provides a semiconductor wafer cutting method for efficiently cutting a plurality of semiconductor wafers simultaneously by one cutting mechanism. The challenge is to provide.

[Means for Solving the Problems] In order to solve the above problems, the semiconductor wafer cutting method according to the present invention employs the following means.

That is, according to the first aspect, the semiconductor wafer having the impurity diffusion layers in which the impurities are diffused on both sides is held by vacuum suction, and is cut into two parts from the center portion of the thickness width by the work rotating inner peripheral cutting machine. In the semiconductor wafer cutting method, a plurality of semiconductor wafers are radially arranged independently in the cutting action plane of the cutting blade of the cutting mechanism, with their outer peripheral portions reinforced, and the semiconductor wafers are arranged at the center of the radial arrangement. It is characterized in that a plurality of semiconductor wafers of three or more are cut into two pieces by one cutting feed operation while rotating around a point.

More specifically, the minimum cutting stroke required to cut a single wafer having a diameter d is (1/2) d, but when cutting a plurality of wafers (n ≧ 3) at the same time, d / n per wafer Therefore, under the same conditions with the same cutting speed, the productivity ratio is n /
It is a double improvement, that is, the larger the number of wafers n,
The effect is great.

According to a second aspect of the present invention, in the method of cutting a semiconductor wafer according to the first aspect, a reinforcing portion is formed on a part of a peripheral edge of the semiconductor wafer, and each of the plurality of independent semiconductor wafers has a radial center point side. It is characterized in that the reinforcing portion is located at a position where a part of the reinforcing portion is left uncut, and the two-divided semiconductor wafer is non-separably cut through the reinforcing portion.

According to a third aspect of the present invention, in the semiconductor wafer cutting method according to the first or second aspect, the main operation for supplying and collecting the unprocessed and processed semiconductor wafers is completed during the semiconductor wafer cutting. It is characterized by

According to a fourth aspect of the present invention, in the semiconductor wafer cutting processing method according to the third aspect, the cutting blade is not used for delivering the unprocessed and processed semiconductor wafer to the holding mechanism that holds the semiconductor wafer and contacts and separates from the cutting blade. It is characterized in that it is performed at the position.

[Operation] According to the above-mentioned means, according to claim 1, a plurality of semiconductor wafers are arranged at a predetermined position with respect to the cutting blade, and are sequentially rotated and linearly moved to sequentially cut the semiconductor wafer. Since a plurality of semiconductor wafers can be cut at twice the single cutting feed stroke, a method of cutting a plurality of (n) semiconductor wafers simultaneously and efficiently with one cutting blade Is solved (where n ≧ 3).

Also, by holding each wafer independently on a fixed reference surface (holding plate), accurate cutting can be performed without interfering with each other.

Further, in the second aspect, in the operation of the first aspect, the cutting end of the semiconductor wafer is reinforced by the reinforcing portion, and the life of the cutting blade is improved because the conventional work-type rotary cutting mechanism uses the point contact cutting method. , Processing distortion is large,
In particular, it is possible to solve the problem that it is difficult to use for cutting a silicon semiconductor because it is damaged at the end of cutting.

Further, in the conventional work rotating type wafer cutting, in order to prevent the wafer to be cut from being cut off from the back side of the cutting blade, a delicate holding device capable of rotating the work in the same direction is required, but it is omitted. Further, it is possible to prevent the processed semiconductor wafer from being separated, and to perform integrated recovery.

Further, in addition to the effect of the first aspect, in the third aspect, the supply and recovery operations of the semiconductor wafer proceed simultaneously with the cutting process, and the cutting efficiency is improved.

According to the fourth aspect of the invention, in the operation of the third aspect, the presence of the cutting blade does not hinder the transfer operation of the semiconductor wafer, and the transfer operation is easy and safe.

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

FIG. 1 is a basic schematic diagram showing an embodiment of a semiconductor wafer cutting method according to the present invention.

FIG. 1 (A) shows a part of the peripheral edge in the cutting action plane of the inner diameter 1 ′ of the cutting blade 1 of the inner peripheral cutting mechanism that cuts the semiconductor wafer W into two halves from the approximate center of the thickness. The three unprocessed semiconductor wafers W each having the reinforcing portion P are arranged so that the reinforcing portions P face each other, and the cutting blade is rotated while rotating the semiconductor wafer W around the center point R of the semiconductor wafer W which is immediately opposite. Three semiconductor wafers W are simultaneously cut in one cutting feed stroke. The reinforcing portion P formed on the semiconductor wafer W is formed by depositing an adhesive or the like or adhering a preformed resin material or the like, and is an impurity diffusion layer in which impurities are diffused on both sides. A thin and hard semiconductor wafer W having qualitative non-uniformity in the thickness direction, for example, is used to prevent damage to the cutting edge, which occurs remarkably in the workpiece rotation type, and a wide reinforcement range is preferable.

As a more efficient example of FIG. 1 (A), see FIG.
4 semiconductor wafers W are arranged as shown in FIG.
It is also possible to arrange five semiconductor wafers W as shown in FIG. In these examples as well, the semiconductor wafers W are arranged in a radial pattern so as to face each other at an equal distance, and the reinforcing portion P is located on the radial center point R side.

According to such an embodiment, as shown in FIG. 2 showing four semiconductor wafers W in FIG. 1 (B), a holding mechanism 2 having a holding plate 2'having a porous suction structure communicating with a vacuum. The semiconductor wafers W are radially arranged and held on the wafer, and a position feed mechanism such as a servo motor is driven to index so that the substantially central portion of each semiconductor wafer W is located within the cutting action plane of the cutting blade. A cutting feed mechanism such as the above is driven to move either one of the cutting blade 1 and the holding mechanism 2, and the holding mechanism 2 is rotated about the center point R to rotate the semiconductor wafer W and four 4 semiconductor wafers W
The two holding plates can be used as reference planes for accurate and simultaneous cutting. Further, if a part of the reinforcing portion P is left uncut, it is possible to maintain the connection of the two-divided semiconductor wafer W through the reinforcing portion P and prevent separation, and the processed semiconductor wafer W is processed.
Can be easily collected, and an elaborate holding device that prevents the wafer from being cut off just before the completion of cutting can be omitted.

In the experimental example of the applicant, in the case shown in FIG. 2, the inner diameter 1'of the cutting mechanism 1 is 240 mm, the diameter of the semiconductor wafer W is 75 mmφ, the thickness is 1.25 mm, and the thickness h of the reinforcing portion P is 10m
m, the distance D between the centers of the respective semiconductor wafers W passing through the center point R is 120 mmφ, the cutting mechanism 1 cuts the holding mechanism 2 at a normal speed, and the holding mechanism 2 rotates at a low speed (tens of rpm) to cut the cutting speed 3
Cutting work was performed with a cutting stroke S of 80 mm at 0 mm / min. As a result, the required cutting time was about 48 seconds, which was less than half the required cutting time for one semiconductor wafer W under the same conditions.

Further, regarding the device configuration for carrying out the method according to the present invention, the position feeding mechanism separates the holding mechanism 2 from the cutting action space of the cutting blade 1 to avoid the cutting blade 1 and to supply and recover a mechanism 5 described later. It is preferable that the semiconductor wafer W can be smoothly transferred to the holding mechanism 2 by enabling the linkage.

Further, a supply / recovery mechanism 5 for supplying and recovering the semiconductor wafer W.
As shown in FIG. 3, is provided with a moving part 51 utilizing a stepping motor or the like capable of reciprocating within a certain range, and two roboting arm parts 52, 53 connected to the moving part 51, It is preferable to complete the main operations of supplying and collecting the semiconductor wafer W during the cutting process.

That is, the moving unit 51 includes a supply unit 6 in which an unprocessed semiconductor wafer W is placed adjacent to a delivery position where the holding mechanism 2 is farthest from the cutting blade 1, and a processed semiconductor wafer W ′.
The first moving unit 51 disposed between the collecting unit 7 and the collecting unit 7
a, a second moving portion 51b that is supported by the first moving portion 51a and complements the reciprocating movement of the first moving portion 51a, and a roboting arm portion that is supported adjacently to the second moving portion 51b at a fixed interval. It is provided with a pair of supply side moving part 51c and recovery side moving part 51d which directly operate 52 and 53. Further, the roboting arm parts 52 and 53 are composed of a supply side moving part 51c and a supply side corresponding to the collecting side moving part 51d and a collecting side, and the rear ends thereof are provided to the supplying side moving part 51c and the collecting side moving part 51d, respectively. The rotatable arms 52a and 53a connected to each other, the rotating portions 52b and 53b such as a geared servomotor or the like serving as a rotation fulcrum of the arms 52a and 53a, and the arms 52a and 5a.
Four supply-side hands 52c, 52d, 52, each of which is attached to the tip of 3a and holds an unprocessed semiconductor wafer W by suction means or the like.
It is provided with four recovery-side hands 53c, 53d, 53e, 53f for gripping the semiconductor wafer W'which has been processed with 52f by suction means or the like. The supply unit 6 and the recovery unit 7 have a cassette structure in which unprocessed and processed semiconductor wafers W and W'can be arranged side by side. A constant stepping motor or the like is used every time the semiconductor wafers W and W'are taken out and stored. Pitch (semiconductor wafers W, W '
It is designed to move in the parallel direction at the time of taking out and storing the number of sheets.

According to such an apparatus configuration, the supply / recovery mechanism 5 is configured such that the first moving part 51a and the second moving part 51b are the most supplying part 6 and the recovering part 7.
Arm 52 of the supply side roboting arm 52 by operating the supply side moving part 51c downward.
Straighten and lower a to supply side hands 52c, 52d, 52e, 52
At f, the four unprocessed semiconductor wafers W stored in the supply unit 6 are rotated and sequentially gripped, and at the same time, the recovery side moving unit 51d.
By the downward movement, the arm 53a of the collecting-side roboting arm portion 53 is straightened and lowered to collect the collecting hands 53c, 53d, 5
The four processed semiconductor wafers W ′ gripped by 3e and 53f are stored in the recovery unit 7. Then, as shown in FIG. 3 (A), the arm 52 of both roboting arm parts 52, 43
a, 53a are raised, and then as shown in FIG. 3 (B), the collecting-side hands 53c, 5 of the collecting-side roboting arm 53 are collected.
3d, 53e, 53f are moved to a position where they can cooperate with the holding mechanism 2, and the unprocessed semiconductor wafer W is formed on the supply-side hands 52c, 52d, 52e, 52f of the supply-side roboting arm portion 52.
4 are prepared, and the completion of the cutting process of the four unprocessed semiconductor wafers W previously held by the holding mechanism 2 is awaited.

That is, during the cutting process of four unprocessed semiconductor wafers W,
Most of the operations of recovering the four processed semiconductor wafers W ′ and supplying new four unprocessed semiconductor wafers W can be simultaneously advanced.

Further, at the end of the cutting process, the holding mechanism 2 is separated from the cutting blade 1 by the position feeding mechanism so that the supply / recovery mechanism 5 can avoid the cutting blade 1 of the cutting mechanism and operate in cooperation with the holding mechanism 2. As shown in FIG. 3 (C), the collecting-side moving unit 51d is moved downward and the collecting-side roboting arm unit 53
Arm 53a is lowered to collect hands 53c, 53d, 53e,
53f holds four processed semiconductor wafers W ',
The suction mechanism of both holding plates 2'of the holding machine 2 is released.

After this, the collection side moving unit 51d is moved upward to move the arm 53a of the collection side roboting arm unit 53 to the collection side hand 53.
Four processed semiconductor wafers W'on c, 53d, 53e and 53f
While holding it, it is raised and the second moving part 51b is moved to a position closest to the transfer position of the holding mechanism 2 as shown in FIG. 3 (D), and the unprocessed semiconductor wafer W is transferred to the holding mechanism 2. After that, the first operation shown in FIG. 3 (A) is repeated.

EFFECTS OF THE INVENTION As described above, the semiconductor wafer cutting method according to the present invention can cut a plurality of semiconductor wafers by one cutting feed operation of the cutting blade according to the first aspect of the invention. There is an effect that can be performed efficiently and accurately.

Furthermore, according to claim 2, in addition to the effect of claim 1,
Due to the peculiarity of the arrangement of the semiconductor wafers to be cut, it is possible to integrally collect the processed semiconductor wafers divided into two parts, and the recovery efficiency of the processed semiconductor wafers becomes good,
Further, there is an effect that the attachment and adjustment of the suction holding device on the opposite side of the holding device that prevents the wafer from being cut off at the end of cutting can be completely eliminated.

Further, according to the third and fourth aspects, in addition to the effects of the first and second aspects, since the steps related to the cutting step are smoothly linked, there is an effect of further improving the cutting efficiency.

[Brief description of drawings]

FIG. 1 (A) is a basic schematic diagram showing an embodiment of a semiconductor wafer cutting method according to the present invention, and FIGS. 1 (B) and (C) are respectively FIG. 1 (A).
Fig. 2 (A) is Fig. 1 (B) showing a more efficient example of
2B is a plan view of FIG. 2A, and FIG. 3 is an operation diagram of a mechanism linked to the semiconductor wafer cutting method according to the present invention. The steps are shown in the order of (D). 1 ... Cutting blade 2 ... Holding mechanism 5 ... Supply / recovery mechanism W ... Unprocessed semiconductor wafer W '... Processed semiconductor wafer P ... Reinforcement part

Claims (4)

[Claims] 1. A semiconductor wafer having a semiconductor wafer having an impurity diffusion layer in which impurities are diffused on both sides thereof is held by vacuum suction and cut into two parts from a center portion of its thickness width by a work rotating inner peripheral cutting machine. In the wafer cutting processing method, a plurality of semiconductor wafers are reinforced in the outer peripheral portion of each of the semiconductor wafers in the cutting action plane of the cutting blade of the cutting mechanism, and are individually arranged radially.
A method of cutting a semiconductor wafer, which comprises cutting three or more semiconductor wafers into two parts by one cutting feed operation while rotating the semiconductor wafer about a center point of a radial arrangement. 2. The method for cutting a semiconductor wafer according to claim 1, wherein a reinforcing portion is formed on a part of the peripheral edge of the semiconductor wafer, and the reinforcing portion is reinforced on the central point side of the radial arrangement of a plurality of independent semiconductor wafers. And a part of the reinforcing part is left uncut, and the semiconductor wafer divided into two parts is cut in a non-separable manner while being a connected body via the reinforcing part. 3. The method for cutting a semiconductor wafer according to claim 1 or 2, wherein the main operation for supplying and collecting the unprocessed and processed semiconductor wafer is completed during the cutting of the semiconductor wafer. A method for cutting and processing a characteristic semiconductor wafer. 4. The method of cutting a semiconductor wafer according to claim 3, wherein the unprocessed and processed semiconductor wafer is delivered to a holding mechanism for holding the semiconductor wafer and bringing it into and out of contact with the cutting blade at a position avoiding the cutting blade. A method for cutting and processing a semiconductor wafer, which is performed.