JPH06318635A - Scribing apparatus for semiconductor wafer - Google Patents

Abstract

PURPOSE:To provide a scribing apparatus for a semiconductor wafer, wherein a cutting scratch in a proper and constant shape can be formed always precisely irrespective of an irregularity in the thickness of the semiconductor wafer. CONSTITUTION:The distance up to a part just under a cutter part 4 in a semiconductor wafer 1 is measured by a distance-measuring device 7 installed integrally with a cutter actuating mechanism part 5. The difference between the measured distance and a preset distance is operated, the up-and-down moving device of a stage stand 2 for wafer fixing is driven so as to make the absolute value of the computed difference zero, the stage stand for wafer dixing is moved up or down, and the stage stand is corrected in such a way that the distance up to the cutter part from the semiconductor wafer becomes constant. After that, the cutter actuating mechanism part is moved up and down and moved horizontally within a constant distance range, and a cutting scratch is formed on the semiconductor wafer by the cutter part. Consequently, the cutting scratch whose length and depth are always proper and constant can be formed precisely irrespective of the thickness of the semiconductor wafer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer scribing apparatus for forming cleavage scratches along a chip of a wafer so as to individually divide a large number of chips formed on a single semiconductor wafer. It is about.

[0002]

2. Description of the Related Art In general, when chips, which are semiconductor elements, are manufactured on a wafer through steps such as diffusion and photo-etching, a plurality of identical chips are regularly arranged on one semiconductor wafer. can get. As a dicing means for dividing the semiconductor wafer into individual chips, a scribing method has been widely used, in which a cutting portion such as a diamond needle is used to form cutting scratches along the chips and then the chips are mechanically divided.

A conventional scribing device based on such a system is generally constructed as shown in FIG.
That is, when the semiconductor wafer (1) is vacuum-sucked and held on the wafer fixing stage base (2) through the vacuum suction holes (3), the wafer fixing stage base (2) moves in the direction of arrow A to the semiconductor wafer (1). ) It is intermittently moved at a constant pitch corresponding to the width of the upper chip (not shown). Above the wafer fixing stage table (2), a cutter operating mechanism section (5) having a cutter section (4) such as a diamond cutter is disposed, and the cutter operating mechanism section (5).
Works as follows. After the wafer fixing stage base (2) is moved by a fixed pitch, it is moved downward by an elevating mechanism (not shown) as shown by the arrow B, and the tip cutting part of the cutter part (4) is moved to the semiconductor wafer (1). A constant load is applied to the inside of the cutter, and then it is moved horizontally in the direction of the arrow C, so that cutting scratches (6) along the chip on the semiconductor wafer (1) at the tip cutting part of the cutter part (4) It is formed like a line. After that, the cutter operating mechanism section (5) moves upward as shown by the arrow D, the cutter section (4) is separated from the semiconductor wafer (1), and the cutter operating mechanism section (5) reaches the upper limit position. The cutter unit (4) is returned to the initial position by moving horizontally in the direction of the arrow E, and then the above-described operation is repeated after the wafer fixing stage base (2) moves by a certain pitch, and cutting scratches along the chip ( 6) is continuously formed. Incidentally, the one-dot chain line shown on the semiconductor wafer (1) is a division virtual line along the chip that is mechanically divided by the cutting scratches (6), but it is set in advance in the manufacture of a semiconductor laser, for example. Sometimes divided by the pitch.

[0004]

By the way, in the above-mentioned scribing device, the vertical motion range of the cutter operating mechanism (5) is constant, and the cutter operating mechanism (5) operates so as to draw an arc rather than a direct downward direction. Therefore, when the thickness of the semiconductor wafer (1) on which the cutting scratches (6) are to be formed varies, or when the thickness varies depending on the location within the same semiconductor wafer (1), the cutting scratches formed are formed. There will be variations in the length and depth of (6). For example, when the thickness is large, long and deep cutting scratches (6) are formed, while when the thickness is small, short and shallow cutting scratches (6) are formed.

In this way, when the cutting scratches (6) cannot be formed to have a proper length and a constant depth, it is possible that the cleavage surface is chipped during the cleavage for division and the cleavage accuracy is lowered. There is a danger, especially when the cutting scratches (6) are too short, it may be impossible to divide the semiconductor wafer (1) into bars by cleavage. In addition, when manufacturing a semiconductor laser element, there is a possibility of causing serious problems such as difficulty in die-bonding and wire-bonding of a laser chip due to variations in laser cavity length, and inconsistent laser characteristics. There is also.

Therefore, the present invention is capable of always accurately forming a cutting scratch having a proper shape even when the thickness of each semiconductor wafer varies or when the thickness varies depending on each location in the same semiconductor wafer. It is a technical object to provide a scribing device for a semiconductor wafer that can be manufactured.

[0007]

According to the present invention, as a technical means for achieving the above-mentioned respective objects, a scribing device for a semiconductor wafer is constructed as follows. That is, in a scribing device for forming cleavage scratches on a semiconductor wafer at a cutter portion, a wafer fixing stage base for fixing the semiconductor wafer and a pitch feed for horizontally moving the wafer fixing stage base by a predetermined distance. An apparatus, a vertical moving device for the wafer fixing stage base, and a cutter portion integrally provided for the semiconductor wafer above the wafer fixing stage base, and a cutting scratch is formed on the semiconductor wafer by the cutter portion. A cutter operating mechanism that moves up and down and moves horizontally within a predetermined distance range, and a measurement that is provided integrally with the cutter operating mechanism to measure the distance to a position directly below the cutter on the semiconductor wafer without contact. The distance measuring device calculates the difference between the distance measured by the distance measuring device and a preset distance, and adjusts the above-mentioned vertical distance so that the absolute value of the difference becomes zero. It is configured as characterized by comprising a control device for driving a device.

[0008]

Before operation of the device, the distance from the position just below the cutter to the tip of the cutter on the semiconductor wafer for forming a cutting scratch of an appropriate length and depth with respect to the vertical movement range of the cutter. Is preset and input to the control device. Then, when the wafer fixing stage base is horizontally moved by a certain pitch by the pitch feeding device, the distance measuring device is then driven to measure the distance to the position directly below the cutter part of the semiconductor wafer (1). At the same time, the measured distance signal is input to the control device. This measured distance signal is
Since the distance measuring device is provided integrally with the cutter operating mechanism, it always corresponds to the distance from the tip of the cutter to the position directly below the cutter on the semiconductor wafer.

Next, the controller calculates the difference between the above-mentioned set distance signal and the measured distance signal input from the distance measuring device, and at the same time, sets the wafer fixing stage table so that the absolute value of the difference becomes zero. Drive control of the vertical movement device. For example, when the drive source of the vertical movement device is a pulse motor, the rotation angle in the required rotation direction of the pulse motor for making the absolute value of the difference zero is calculated, and the pulse corresponding to that rotation angle is used as the pulse motor. And the pulse motor is controlled to rotate by the calculated rotation angle, and the wafer fixing stage base is moved up or down. Therefore, before the formation of cutting scratches,
The vertical position of the wafer fixing stage base, that is, the semiconductor ware is corrected so that it is always constant regardless of the thickness of the semiconductor ware, and then the cutter operating mechanism is vertically moved and horizontally moved within a constant distance range. As a result, a cutting scratch is formed on the semiconductor wafer, so that a cutting scratch having an appropriate length and a constant depth is always accurately formed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows a schematic configuration of an embodiment of the present invention. In the figure, the same or equivalent parts as those in FIG. 4 are designated by the same reference numerals, and the description thereof will be omitted. Only the different configuration will be described next. . Distance measuring device (7) arranged so as to move integrally with the cutter operating mechanism (5)
Is a distance (h) from a predetermined position of the cutter operating mechanism (5) to a position immediately below the cutter (4) in the semiconductor wafer (1) where a cutting scratch (6) is to be formed, for example, Non-contact measurement is performed based on the time from when the ultrasonic wave is emitted to when the ultrasonic wave is reflected and returned. The wafer fixing stage base (2) is held so as to be movable up and down, and a rack portion (8) is integrally hung from the lower surface as an operating member for vertically moving the rack portion (8). ) Is engaged with a transmission gear (9), and further, the transmission gear (9)
The drive gear (12) fixed to the motor shaft (11) of the pulse motor (10) is meshed with. Therefore, the forward or reverse rotation of the pulse motor (10) is transmitted to the rack portion (8) via the drive gear (12) and the transmission gear (9), so that the wafer is integrated with the rack portion (8). The stationary stage base (2) can be moved up or down. The pulse motor (10) and the transmission gear (9) are designed to be horizontally pitch-moved integrally with the wafer fixing stage base (2) while maintaining their meshed states.

FIG. 2 is a block diagram of the above-described embodiment. The same parts as those in FIG. 1 are designated by the same reference numerals, and the central processing unit (13) causes the entire device to follow the flow chart of FIG. It is configured to be controlled and processed. A reference distance (height) from a position directly below the cutter unit (4) on the semiconductor wafer (1) to a predetermined position corresponding to the distance measuring device (7) of the cutter operating mechanism unit (5) by the operation panel (14). Is set, the set distance is compared with the measured distance input from the distance measuring device (7), and the pulse motor (10) is passed through the driver (20) so that the difference becomes zero. By controlling the rotation in the direction of, the height of the wafer fixing stage base (2) is adjusted so that the distance from the tip of the cutter unit (4) to the surface of the semiconductor wafer (1) directly below the cutter unit (4) becomes constant. , Driver (1
8) The cutting drive mechanism section (21) is drive-controlled to vertically and horizontally move the cutter operation mechanism section (5), and then the pitch feed device (22) is drive-controlled through the driver (19) to fix the wafer. The stage table (2) is moved by a predetermined pitch. At this time, a pulse motor (10) constituting a vertical movement mechanism of the wafer fixing stage base (2),
It goes without saying that the drive gear (12) and the transmission gear (9) are also moved integrally with the wafer fixing stage base (2).
The wafer recognition circuit (15) recognizes the presence or absence and the position of the semiconductor wafer (1) from the image data signal of the semiconductor wafer (1) picked up by the camera (16), and monitors the data. Although reflected in (17), it is a configuration not directly related to the present invention.

Next, the operation of the above embodiment will be described with reference to the flowchart of FIG. Prior to driving the apparatus, a semiconductor wafer for forming cutting scratches (6) having an appropriate length and depth with respect to the vertical movement range of the cutter unit (4) set in the central processing unit (13) The distance from the position directly below the cutter (4) in (1) where the cutting scratch (6) is to be formed to the predetermined position of the cutter operating mechanism (5) is set from the operation panel (14) to the central processing unit. (13)
Enter the setting. Then, in actual operation, the central processing unit (13) drives and controls the pitch feed unit (22) through the driver (19) to move the wafer fixing stage base (2) horizontally by a fixed pitch (step S1), the distance measuring device (7) is driven thereafter, and the distance from the distance measuring device (7) shown in FIG. 1 to the place where the cutting flaw (6) is to be formed next to the semiconductor wafer (1) ( h) is measured, and the measured distance signal is measured by the central processing unit (1
3) is input (step S2). Since the distance measuring device (7) is provided integrally with the cutter operating mechanism (5), the measured distance signal is transmitted from the tip of the cutter (4) to the semiconductor wafer (1) and then the cutting scratch (6). Always corresponds to the distance to the point where

Then, in the central processing unit (13), the difference between the set distance signal preset and input from the operation panel (14) and the measured distance signal input from the distance measuring device (7) is calculated ( Next, in step S3), it is determined whether or not the calculated absolute value of the difference is equal to or less than the allowable value (step S4). Now, if the absolute value of the difference is equal to or greater than the allowable value, a pulse motor (10) for making the difference zero
The rotation angle of the rack is calculated (step S5), a pulse corresponding to the rotation angle is supplied from the driver (20) to the pulse motor (10), and the pulse motor (10) is rotationally controlled by the calculated rotation angle. The wafer fixing stage base (2) is moved up or down via the unit (8) (step S6).

The above processing will be described in detail. For example, when the measured distance data (h) is smaller than the set distance data (H) due to the large thickness of the semiconductor wafer (1),
The value of the difference Δh that satisfies H = h + Δh is calculated. Now, in order to simplify the explanation, assuming that H = 100 and h = 90,
Since Δh = 10, the wafer fixing stage base (2) should be lowered by this Δh. Assuming that the wafer fixing stage base (2) moves up or down by "1" by applying 1 pulse to the pulse motor (10) and rotating it by 1 step, the pulse motor (10) is By applying 10 pulses to rotate in the positive direction indicated by the arrow in FIG. 1, the transmission gear (9)
Rotates in the direction of the arrow, and the rack portion (8), that is, the wafer fixing stage base (2) moves downward by "10", and the cutter operating mechanism portion (5 The distance to the predetermined position in () matches the set distance (H). That is, the distance from the place where a cutting flaw is to be formed next to the semiconductor wafer (1) to the tip of the cutter portion (4) is the set value.

On the other hand, when the measured distance data (h) is larger than the set distance data (H) due to the small thickness of the semiconductor wafer (1), the value of the difference Δh, which is H = h-Δh, is calculated and the pulse is calculated. By applying a calculated number of pulses to the motor (10) so as to rotate in the opposite direction shown by the opposite arrow in FIG. 1, the transmission gear (9) rotates in the opposite arrow direction so that the rack portion (8), that is, the wafer. The fixed stage base (2) moves upward by a step corresponding to the number of supply pulses, and the distance from the position where the cutting scratch (6) is to be formed on the semiconductor wafer (1) to the tip of the cutter part (4) becomes a set value. Match.

After that, the central processing unit (13) drives and controls the cutting drive mechanism section (21) via the driver (18) to lower the cutter operating mechanism section (5) to the lower limit position, and then to the horizontal position. Moving in the direction, cutter part (4)
Thus, a cutting scratch is formed on the semiconductor wafer (1) (step S7), and subsequently, the cutter operating mechanism section (5) moves up to the upper limit position and then horizontally moves to return the cutter section (4) to the initial position. (Step S8). After that, step S1
And the same processing as described above is repeated.
When the absolute value of the difference is less than or equal to the allowable value or zero, the cutting drive mechanism section (21) is immediately driven and controlled, the cutter operating mechanism section (5) is operated, and the cutter section (4) is operated. Cutting scratches are formed (step S7).

[0017]

As described above, according to the semiconductor wafer scribing apparatus of the present invention, the distance from the cutter portion to the portion of the semiconductor wear immediately below the wafer is determined according to the thickness of the semiconductor wear before the formation of the cutting scratch. By adjusting the vertical position of the stationary stage base, that is, the semiconductor ware, it is adjusted to be constant at all times, and then the cutter operating mechanism is vertically moved and horizontally moved within a certain distance range so that the cutter moves on the semiconductor wafer. Since the cutting scratches are formed on the surface, it is possible to always form a cutting scratch having an appropriate length and a constant depth accurately, and the cleaving work after the formation of the cutting scratches can be performed with good reproducibility and high accuracy. Further, there is an advantage that the work of adjusting the height of the cutter operating mechanism unit is not required every time the semiconductor wafer on which the cutting scratch is to be formed is different, and the work efficiency is remarkably improved.

[Brief description of drawings]

FIG. 1 is a front view showing a schematic configuration of an embodiment of the present invention.

FIG. 2 is a block diagram showing the same as above.

FIG. 3 is a flowchart of the same.

FIG. 4 is a perspective view showing a schematic configuration of a conventional device.

[Explanation of symbols]

1 Semiconductor Wafer 2 Wafer Fixing Stage 4 Cutter 5 Cutter Actuator 7 Distance Measuring Device 8, 9, 10, 12 Rack, Transmission Gear, Pulse Motor, Drive Gear (Up / Down Device) 13 Central Processing Unit ( Control device) 22 Pitch feed device

Claims (1)

[Claims] 1. In a scribing device for forming a cutting scratch for cleavage on a semiconductor wafer at a cutter portion, a wafer fixing stage base for fixing the semiconductor wafer and the wafer fixing stage base are horizontally moved by a predetermined distance. A pitch feed device, a vertical movement device for the wafer fixing stage base, and the cutter portion integrally with the semiconductor wafer at a position above the wafer fixing stage base, and a cutting scratch on the semiconductor wafer by the cutter portion. A cutter operating mechanism that is vertically moved and horizontally moved within a predetermined distance range so as to form a non-contact distance to a position directly below the cutter on the semiconductor wafer that is provided integrally with the cutter operating mechanism. Before calculating the difference between the distance measuring device to be measured and the measured distance of this distance measuring device and the preset distance, the absolute value of the difference becomes zero. A semiconductor wafer scribing device comprising: a controller for driving the vertical movement device.