JPH0523514B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a point scribing device for making a scratch on a flat compound semiconductor for a laser diode in order to perform a cleavage operation.

(Prior Art) Conventionally, an apparatus for cutting a silicon wafer into chips of a predetermined size is known. This device performs a so-called full scribing operation in which the surface of a silicon wafer is scratched in a square pattern and split into chips along the square scratches.

On the other hand, a laser diode has a size of about 250 microns square, and is obtained by cleaving a flat compound semiconductor having a size of about 1 cm square and a thickness of about 100 microns. Since a laser diode emits laser light from a cleavage plane, the shape of the cleavage plane is particularly important.

(Problems to be Solved by the Invention) The conventional apparatus described above is configured to inflict scratches on the surface of a workpiece in a grid pattern. Therefore, if this configuration is adopted for a cleavage operation in which a laser diode is obtained by dividing the laser diode into a predetermined size while exposing the cleavage plane, the problem remains that the cleavage plane is not neat due to the scratches made.

Further, although the above-mentioned device is suitable for making relatively long straight scratches, it cannot precisely make short scratches that can accurately determine the direction of cracking. Therefore, even if this configuration is adopted for cleavage work, it will not be possible to accurately produce a predetermined cleavage plane.
This leaves the problem that the yield of the product becomes extremely poor.

The present invention attempts to solve the above problems.

(Means for Solving the Problems) A point scribing device according to the present invention places a flat semiconductor workpiece on which a large number of laser diodes are formed, and scribes it in two orthogonal axes in a plane parallel to the plane of the semiconductor workpiece. a workpiece feeding table that is movable in (X-Y directions), and a cutter mechanism that is arranged above the workpiece feeding table and that allows a scribing cutter to be moved up and down in a direction (Z direction) perpendicular to the plane of the semiconductor workpiece. , semiconductor work W to be scribed
scribing information input operation means corresponding to the shape and dimensions of the workpiece, including at least the moving speed of the workpiece feed table, scribing interval, scribing length, scribing speed, scribing groove depth, and vertical/downward moving speed of the cutter; Next control step: Set the scribing cutter to the origin position; Set the cutter to a predetermined height position on the plane of the semiconductor workpiece; Move the workpiece feed table relative to the cutter at a predetermined speed in the scribing direction. Transfer; Simultaneously with the transfer of the workpiece feeding table, the cutting edge of the cutter is lowered at a predetermined speed into the semiconductor work fixed to the workpiece feeding table; The cutting edge of the cutter reaches a predetermined depth position within the semiconductor workpiece. rear,
While maintaining the depth position, the workpiece feeding table is transported a predetermined scribing distance at a predetermined scribing speed relative to the cutter; scribing the semiconductor workpiece with a length l in a predetermined direction (Y direction) After completion of the process, the cutter is raised again at a predetermined speed to the same height position as when scribing was started; and, while the transfer of the workpiece feeding table is stopped, the cutter is raised at a predetermined speed to the scribing pre-adjustment height position. The present invention is characterized by comprising an electronic control unit that controls the movement of the work feed table and the scribing cutter according to a control routine that includes the following steps:

(Function) First, a flat compound semiconductor for a laser diode is placed on a table. Next, the cutter attached to the cutter head is lowered to a predetermined height above the compound semiconductor, and then the table is slid relative to the cutter by a predetermined distance at a predetermined scribing speed. As the table slides, the cutter is lowered at a predetermined scribing speed, the cutter is then held at a predetermined depth within the compound semiconductor, and then the cutter is raised at a predetermined scribe speed.

As a result, a ship-shaped scratch suitable for linearly dividing the compound semiconductor to obtain a predetermined cleavage plane is formed on the compound semiconductor.

(Example) In FIG. 2 showing the appearance of the point scribing device according to the present invention, the lower part of the desk-shaped pedestal 11 is
A control box 12 having a CPU and a motor driver is provided. A device main body 13 is placed on the pedestal 11, and a keyboard box 14, a stake controller box 15, and a monitor 16 are also placed for inputting numerical values for controlling the device main body 13 and for controlling the device main body 13. ing.

As shown in FIG. 3, a support table 17 is fixed to the rear of the apparatus main body 13, and a microscope 18 through which the operator looks is supported on the support table 17 so as to be movable up and down, back and forth, and left and right. There is. As the microscope 18, for example, a binocular zoom stereo microscope with a magnification of 5 to 400 times is used. A table 19 is arranged on the upper front surface of the apparatus main body 13, and a microscope 18 is arranged above the table 19. A base portion of a cutter head 20 is supported at the rear of the device body 13, and a cutter 21 attached to the tip of the cutter head 20 is disposed above a table 19.

As shown in FIG. 1, which is a schematic diagram of the internal structure of the device main body 13, the table 1 is placed on a base 25.
9 is the table guide 26 and is guided by it
X-axis table 2 that moves in the axial direction (arrow X direction)
7, and the X-axis table 27 is driven and controlled by an X-axis pulse motor 28. A table guide 29 is placed on the X-axis table 27, and a Y-axis table 30 that is guided by the table guide 29 and moves in the Y-axis direction (arrow Y direction) is fitted into the table guide 27. The drive is controlled by a Y-axis pulse motor 31. A θ table 32 is placed on the Y-axis table 30, and the θ table 32 is rotated along the vertical axis (Z) by a θ-direction pulse motor (not shown).
The rotation is controlled in the θ direction around the shaft. Further, the upper end surface of the θ table 32 is formed horizontally. Although not shown, a large number of small holes are formed in the upper end surface of the θ table 32, and a pressure reducing mechanism is connected to the small holes through the inside of the θ table 32. That is, the upper end surface of the θ table 32 has a function of vacuum suction.

On the other hand, the cutter head 20 is installed at the tip of a cantilever lever extending in the diametrical direction of the θ table 32. A cutter 21 fixed to a cutter head 20 is placed above a θ table 32.
The base of the cutter head 20 is fixed to an intermediate portion of a support shaft 35 extending parallel to the X direction in a radially protruding position. Both ends of the support shaft 35 are connected to a pair of supporters 36 whose lower ends are fixed to the base 25.
It is rotatably supported at the top of the. An upper side surface of a Z-axis arm 37 extending in the vertical direction is connected to a portion of the support shaft 35 that protrudes in the X direction from one supporter 36.
If it moves in the direction, the support shaft 35
rotates. The lower end of the Z-axis arm 37 is screwed onto a ball screw 38 extending in the Y direction, and the rotation of the ball screw 38 causes the lower end of the Z-axis arm 37 to move in the Y direction. ing. A drive shaft of a Z-axis pulse motor 39 is connected to one end of the ball screw 38, so that the rotation of the ball screw 38 is controlled thereby. Note that this link mechanism allows the Z-axis arm 37
The amount of movement in the Y direction and the amount of movement in the Z direction of the tip of the cutter 21 attached to the cutter head 20 correspond in a 1:1 ratio.

As shown in FIG. 4, the cutter head 20 is mainly formed of a cutter head body 40 and an arm 41 that projects forward from the cutter head body 40. The base of the arm 41 is supported by the cutter head body 40 so as to be rotatable about an axis in the X direction within the cutter head body 40, and is always elastically biased downward by a spring (not shown). The biasing force of the spring against the arm 41 can be adjusted by manually rotating a spring adjustment knob 42 to press the cutter 21 downward. In compound semiconductor scribing work, the biasing force of the spring is set so that the load at the tip of the cutter 21 is about 5 to 35 g, more preferably about 20 g. The cutter 21 is held generally downward at the tip of the arm 41 that protrudes generally in the Y direction. The cutter 21 can be rotated around the axis in the X direction by loosening the angle adjustment knob 43 provided on the side of the tip of the arm 41, and the operator manually adjusts the inclination angle of the cutter 21 with respect to the horizontal plane. It is adjustable. Further, the cutter 21 can be released from being held by loosening a cutter removal knob 44 provided on the side of the tip end of the arm 41, thereby allowing the cutter 21 to be replaced.

As the cutter 21, for example, a three-point diamond cutter is used. cutter 2
1 has a truncated conical part formed at one end of a cylindrical member, and a triangular pyramid-shaped diamond cutter is fixed to the truncated conical part, as shown in FIG.
During scribing work, any one of the three corners 45 of the diamond cutter
People are starting to use one.

Next, the operation will be explained.

First, set the data necessary to perform the scribing work. Determine the moving speed (1), moving step width (2), and number of steps (3) of the X-axis table 27 in FIG. 1, and determine the moving speed (4), moving step width (5), and number of steps of the Y-axis table 30. (6)
Determine the moving length of the Y-axis table 30 when scribing, that is, the length of the scratch (7) and the speed when scribing.
(8), the vertical speed of the cutter 21 (9), and the descending distance of the cutter 21 from a predetermined height, that is, the depth of the scratch.
Determine (10). These determined values are entered using the keyboard box 14 in FIG.

After entering the data, the microscope 18 (Fig. 2)
The work is performed to align the intersection of the cross lines drawn on the eyepiece with the scribing start position of the semiconductor workpiece. The workpiece is placed on the θ table 32 in Figure 1.
Place it on top and fix it by vacuum suction. The workpiece is pre-patterned to create, for example, a 250μ square laser diode. A flat semiconductor work W in which a large number of laser diodes are integrated is, for example, 1 cm square and 100 μm thick. An operator manually operates a stake provided in a stake controller box 15 (FIG. 2) to bring the workpiece into the field of view of the microscope 18 using the stake control. Also, θ table 3
2 in the θ direction to orient the sides of the workpiece in the X and Y directions.

Once the workpiece has been set, the scratches are made only once in the same manner as described later. While moving the microscope 18 using the scratch as a mark, the microscope 1
Turn the eyepiece No. 8 to align the scratch with the cross line in the Y direction, and also align one end of the scratch with the intersection of the cross lines. For confirmation, the X-axis table 27 is moved by one movement step width (2) and the scratch is made once again. The new wound is under the microscope 18
If the cross line of the microscope 18 is on the cross line and one end of the scratch coincides with the intersection, it means that the cross line of the microscope 18 and the scratch starting position coincide. Note that it is necessary to align this cross line with the incision start position each time the angle and length of the cutter 21 are changed.

Next, a scribing operation is automatically performed based on the input data. The basic arrangement of the scratches is shown in FIG. In FIG. 6, W represents a workpiece, S represents a scratch made on the surface of the workpiece W, and the numbers in parentheses correspond to the above input data.

For example, it is assumed that the scratch is made starting from the scratch S at the upper left corner. The length of the scratch S is determined by data (7), specifically, by the amount of movement of the Y-axis table 30 by the Y-axis pulse motor 31. If there is one scratch S, data (2)
The workpiece W is moved one step in the X direction based on the data (7), and then a scratch S with the length of data (7) is created.
The moving speed of the workpiece W in the X direction is determined by data (1), specifically, the moving speed of the X-axis table 27 by the X-axis pulse motor 28.

Once a predetermined number of scratches S are made in the X direction as many times as data (3), the next scratches S are made at predetermined intervals in the Y direction based on data (5). The moving speed in the Y direction is determined based on data (4), specifically, the moving speed of the Y-axis table 30 by the Y-axis pulse motor 31. Again, data (1),
A predetermined number of scratches S are made at predetermined intervals based on (2), (3), and (7). By repeating this operation the number of times based on data (6), scribing on one workpiece W is completed.

Each wound S is made as shown in FIG. 7th
In the figure, is the origin position of the cutter 21. First, the cutter 21 is lowered to the position.
This vertical movement is performed by rotation of the ball screw 38 by the Z-axis pulse motor 39. Next, the cutter 21 is moved relative to the workpiece W in the Y direction. This movement is performed by the Y-axis pulse motor 31.
This is done by moving the axis table 30 in the Y direction, and the moving speed is based on data (4).
Further, this amount of movement corresponds to the amount of offset provided to ensure the field of view of the microscope 18.
This offset prevents the cutter 21 from moving out of the field of view of the microscope 18 and preventing the operator from being able to check the state of the wound S using the microscope 18.

The cutter 21 is moved further downward from the position. The movement speed at that time is based on data (9), and is much slower than the speed between. When the cutter 21 comes to a position at a certain predetermined height (for example, 150μ height) from the upper end surface of the workpiece W, the workpiece W is moved in the Y direction by the Y-axis table 30 at the speed of data (8). At the same time, the cutter 21 starts descending at a constant speed. As a result, the cutter 21 moves relative to the work W from the position . The movement speed based on data (8) at that time is much slower than data (4). The descending distance of the cutter 21 from to is based on data (10).

When the cutting edge of the cutter 21 reaches a predetermined depth position from the surface of the semiconductor workpiece W, the cutter 21
is held at that depth position. Therefore, from then on, the workpiece W is scratched at a constant depth. After the cutter 21 reaches the position, the workpiece W is transferred by the length (1) based on the data (7), and when the cutter 21 reaches the position relative to the workpiece W, the workpiece is moved from the above-mentioned position. It is raised in the same way as in the lowering operation of. The movement speed at that time is based on data (9). data
When the cutter 21 rises by the distance based on (10) and reaches the position, the movement of the workpiece W in the Y direction stops. From then on, the cutter 21 is only raised in the same way as in the lowering operation from the position to the position . The workpiece W moves from the position at a speed based on data (4), and the cutter 21 returns to the relative position.
Further, the cutter 21 moves upward and returns to the origin. That is, the cutter 21 returns to the position offset from the wound S, and the field of view of the microscope 18 is secured.

The planar shape of the resulting scratch S becomes a boat shape as shown in FIG. During the cleavage operation, the workpiece W is split in a straight line in the extending direction of the boat-shaped tip. The length of the scratch S is about 30 to 250μ, the width is about 7 to 8μ, and the depth is about 14 to 16μ. Once the cleavage process has been completed, each laser diode is 250μ square in size, and the product is completed by wiring with a bonder and molding.

In the actual scribing operation, it is preferable to perform the following process instead of making the scratches S vertically and horizontally on the entire surface of the workpiece W at once. First, a row of scratches S is made only in the vicinity of one side of the work W by the above method. That is, data (4), (5), and (6) are not used. Next, the workpiece W is divided into strips based on the scratches S to expose cleavage planes. This surface becomes the surface that emits the laser. After coating this cleavage plane with a protective film, scratches S are made to break each strip-shaped workpiece W into 250 μ square chips. In this case, the length of the scratch S is about 100 to 150 μm, and the scratch S is made at the middle part of the strip-shaped workpiece W in the width direction. That is, since no scratches S are made on the edges of the strip-shaped workpiece W, the scratches S do not adversely affect the cleavage plane from which the laser is emitted. Also, in this case, data (4),
A row of scratches S is created by the above method without using (5) and (6).
Attach. Finally, cut the workpiece W into chips,
The product is completed by wiring with a bonder and molding.

(Another embodiment) (a) Instead of the microscope 18 or together with the microscope 18
It is also possible to install a CCD camera and position the workpiece W by image recognition by a computer.

In that case, a configuration may be adopted in which two cameras are used, one with low magnification and the other with high magnification. By performing overall positioning with a low-magnification camera and precise positioning with a high-magnification camera, there is an advantage that work can be performed quickly and accurately.

(b) It is also possible to install an automatic loader so that the work W can be loaded and unloaded automatically.

(Effect of the invention) In the point scribing device of the present invention,
Scribing information set according to the shape and dimensions of the semiconductor workpiece W to be scribed is input into the electronic control unit, and the electronic control unit sequentially transports the workpiece feeding table and scribing cutter according to a predetermined control routine. By using numerical control, the following effects can be obtained: (a) The cleavage process to obtain minute laser diode chips can be performed accurately and efficiently; (b) The semiconductor to be scribed can be By simply changing the input data according to the shape of the workpiece, it is possible to make scratches in the desired shape very efficiently, making it possible to manage data on the scribing shape, making it suitable for the mass production process of laser diodes. can do.

[Brief explanation of the drawing]

FIG. 1 is a perspective view schematically showing the internal structure of a laser diode point scribing device according to the present invention, FIG. 2 is a front view schematically showing the entire structure, and FIG. Figure 4 is a perspective view of the cutter head, Figure 5 is a bottom view of the cutter,
FIG. 6 is a schematic plan view showing the position of the scratch on the workpiece, FIG. 7 is a side view showing the locus of the cutter, and FIG. 8 is a plan view showing the detailed shape of the scratch. 19... table, 20... cutter head, 21... cutter.

Claims (1)

[Claims] 1. A flat semiconductor workpiece on which a large number of laser diodes are formed is placed and movable in orthogonal biaxial directions (X-Y directions) in a plane parallel to the plane of the semiconductor workpiece. A work feed table, a cutter mechanism which is arranged above the work feed table and is capable of vertically moving a scribing cutter in a direction perpendicular to the plane of the semiconductor work (Z direction), and a shape and shape of the semiconductor work W to be scribed. At least the movement speed of the workpiece feed table (data 1, 10), scribe interval (data 2, 5), scribing length (data 7), scribing speed (data 8), and scribe groove depth (data 10) corresponding to the dimensions. ), and the top of the cutter.
scribing information input operation means including the downward movement speed (data 9), and at least the following control steps: setting the scribing cutter to the origin position; setting the cutter to a predetermined height position on the plane of the semiconductor workpiece; The workpiece feed table is transferred relative to the cutter in the scribing direction (Y direction) at a predetermined speed; At the same time as the workpiece feed table is transferred, the cutting edge of the cutter is directed into the semiconductor work fixed to the workpiece feed table. After the cutting edge of the cutter reaches a predetermined depth position in the semiconductor workpiece, while maintaining that depth position, move the workpiece feeding table relative to the cutter at a predetermined scribing speed. After scribing the semiconductor workpiece for a length (l) in a predetermined direction (Y direction), raise the cutter again at a predetermined speed to the same height position as when scribing started. and stopping the transfer of the workpiece feeding table and raising the cutter at a predetermined speed to the scribing pre-adjustment height position, and then returning it to the home position. A point scribing device for a laser diode, comprising an electronic control unit that controls the transfer of a scribing cutter.