JP2576421B2 - Dicing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cutting and dividing a plurality of semiconductor circuit elements arranged in a matrix on a circular wafer as a semiconductor substrate into individual semiconductor circuit elements by a rotating disk-shaped blade. It relates to a dicing device.

[0002]

2. Description of the Related Art Generally, in the manufacture of semiconductor devices,
After forming a large number of semiconductor circuit elements on a wafer with a large diameter in a row, they run along the scribe line that separates the semiconductor circuit elements on the wafer while rotating a blade embedded with diamond abrasive grains in a metal bond. And divided into individual semiconductor circuit element pieces, that is, chips. Further, a cooling liquid has been sprayed onto the blade and the wafer in order to prevent heat generation of the wafer and burnout of the blade generated during the cutting, and to remove chips generated by the cutting from the wafer. Furthermore, since the semiconductor circuit elements on the wafer require a high degree of cleaning, expensive pure water had to be used as the grinding fluid.

FIG. 2 is a view schematically showing an example of a conventional dicing apparatus, and FIG. 3 is a plan view showing the wafer of FIG. Conventionally, as shown in FIG. 2, this type of dicing apparatus includes a chuck table 3 for holding a wafer 11 together with a holder 7, a rotation driving unit 6a for rotating the blade 1 at a constant rotation speed of 30.000 rpm, Nozzle 9a that injects pure water 10 supplied from control unit 2a
A driving mechanism 4a for moving the chuck table 3 relative to the blade 1;
a and a control unit 5a for controlling the drive mechanism unit 4a.

In order to cut a wafer with this dicing apparatus, first, the chuck table 3 is moved by a signal from a control unit 5a, and as shown in FIG. The trajectory 12 is drawn and one direction of the wafer 11 is ground and cut by the blade 1, and then the chuck table 3 is rotated by 90 degrees. It has been cut and divided into individual pieces of semiconductor circuit elements.

A control unit 5 for controlling a driving mechanism 4a for moving the chuck table 3 and a rotation driving unit 6a for rotating the blade 1 during the grinding and cutting along the locus 12.
The flow rate of the pure water 10 was set by the flow rate control unit 2a independently of a, and a certain amount of the pure water 10 was jetted from the nozzle 9a to the blade 1 and the wafer 11.

[0006]

In the above-mentioned conventional dicing apparatus, the supply amount of the pure water 10 is kept constant even when the wafer 11 is cut or not.
Was ejected from the nozzle 9a as long as the vehicle was traveling. In addition, in order to perform sufficient cooling, the amount was supplied in excess of the amount required for cleaning. Therefore, even when the wafer 11 is not actually cut (the locus 12 other than on the wafer 11 in FIG. 3), the pure water 10 is continuously supplied and the expensive pure water 10 is wasted. Further, if the rotation speed of the blade 1 and the moving speed of the chuck table 3 are increased in order to improve the production capacity with the increase in the size of the wafer 11, the amount of chips increases. Of course,
The supply amount of the pure water 10 is set according to the amount of generated chips, and the pure water 10 is further wasted.

On the other hand, even when the wafer 11 is not cut, since the blade 1 is rotating at a high speed, the jetted pure water collides with the blade 1 and the diamond particles and the diamond particles which are about to be detached from the metal bond. The chips interposed between the grains are more likely to be separated by the rotational force and the jetting force of the pure water, and there is a problem that the grains and the chips are scattered from the blade 1 and adhere to the surface of the wafer 11. The semiconductor circuit element pieces to which the granules and chips have adhered cause serious quality problems in a later process.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a dicing apparatus which requires less consumption of pure water and can cut the wafer while keeping the wafer clean.

[0009]

SUMMARY OF THE INVENTION The feature of the present invention is that a plurality of semiconductor circuit elements arranged and formed in a matrix on a circular wafer as a semiconductor substrate are individually rotated by a disk-shaped blade. In a dicing device that cuts and divides into elements, a rotation drive unit that rotates the blade,
A chuck table for holding and moving the wafer,
A driving unit that moves the chuck table to relatively move the wafer and the blade, a nozzle that injects pure water to the blade and the wafer, and the pure water while the blade is cutting the wafer. A dicing apparatus comprising: a controller configured to set an injection amount to an appropriate amount and set the injection amount of the pure water to be smaller than the appropriate amount when the blade does not cut the wafer. Also,
It is preferable that the rotation speed of the blade when the wafer is not cut is lower than the rotation speed when the wafer is cut.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIGS. 1A and 1B are a schematic diagram and a time chart of a dicing apparatus for explaining an embodiment of the dicing apparatus according to the present invention. As shown in FIG. 1 (a), this dicing apparatus uses a suitable pure water while the blade 1 cuts the wafer 11 every time the blade 1 and the wafer move relatively in one direction. When the ejection amount is set to 10 and the blade 1 does not cut the wafer 11, a program sequencer 8 that programs the flow rate of the pure water 10 to be set smaller than an appropriate amount is connected to the control unit. The other drive mechanism 4, chuck table and holder 7, and nozzle 9 are the same as in the conventional example.

It is desirable that the rotation speed of the blade 1 when not cutting is set lower than the rotation speed during cutting by the program sequencer 8. This program sequencer 8 can be a commercially available program sequencer without special design and manufacture, and can be modified simply by assembling it into a conventional dicing apparatus.

The setting for the program sequencer 8 is as follows:
For example, as shown in FIG. 1B, switching of the opening and closing of valves 13a and 13b of flow control units 2b and 2c having different set flow rates of pure water 10 for each stroke of blade 1 traveling on wafer 11 surface. And the timing of the speed switching of the rotation drive unit 6 are programmed.

The flow rate control units 2b and 2c are a kind of flow rate control valve. The flow rate control unit 13a on the high flow rate side is preset to, for example, 3.3 l / min, and the flow rate control unit on the low flow rate side is set. If 2c is set to, for example, 1 l / min, the valves 13a and 13b are opened and closed at an arbitrary time every minute.
3 liters or 1 liter per minute of pure water 10 can be spouted.

On the other hand, the switching of the number of rotations of the blade 1 in the rotary drive unit 6 is performed by, for example, a coaxial electromagnetic clutch / brake built in the rotary drive unit 6. Then, the blade 1 starts to cut the wafer 11, the electromagnetic clutch is operated until the cutting is completed, and the blade 1 is rotated at an appropriate rotation speed. When the cutting is completed and the blade 1 is simply traveling in an area other than the wafer 11, When the vehicle is traveling to pass over the wafer 11 and return to the original position side, the electromagnetic brake is actuated to reduce the rotational speed to a predetermined rotational speed, and release the electromagnetic brake when the rotational speed reaches the predetermined rotational speed. Then, when the cutting of the wafer 11 is started again, the electromagnetic clutch is operated to set the blade 1 to an appropriate rotation speed.

Next, the operation of the dicing apparatus will be described. First, the timing of the valves 13a and 13b and the timing of switching the number of revolutions of the blade 1 are set for each stroke of the blade 1 when cutting the wafer 11 in the program sequencer 8 in advance. And the wafer 11
Is attached to the chuck table 3 together with the holder 7 composed of an adhesive sheet and a frame.

Next, the positions of the blade 1 and the chuck table 3 are set to the origin positions. Although not shown in the drawing, this origin position is a position where the blade is farthest from the wafer 11 and where the running line of the blade 1 coincides with the outermost scribe line of the wafer 11. Next, at the origin position, the blade is rotated at a low speed, for example, 8000 rpm by the operation of the electromagnetic clutch / brake described above. At the same time, the valve 13a closes and the valve 13b is opened, and pure water flows at, for example, 1 l / min. Then, the feed speed at the time of cutting the chuck table 3 is set to, for example, 80 mm / min, and the return speed of the blade 1 is set to, for example, 300 mm / min.

Next, when the chuck table 3 moves from the origin position and the blade 1 reaches the point P1, the rotation driving unit 6
And the program sequencer 8 switches the blade 1 to high-speed rotation. Further, when the blade 1 reaches P2, the valve 13b is closed and the valve 13a is opened, and the discharge amount of the pure water 10 from the nozzle 9 is increased to, for example, 3.3 l / min. The number of revolutions of the blade 1 is, for example, 3000 per minute.
When the rotation amount of the pure water 10 reaches 0 l / min, the blade 1 starts to cut the wafer 11. Here, when setting the distance between the points P1 and P2 and the edge of the wafer 11, the arrival time to the wafer edge by the feed speed of the chuck table 3, the rise time of the high-speed rotation of the blade 1, and the rise time of the supply speed of pure water are set. It is desirable to decide in consideration of.

Next, when the blade 1 reaches the point P3, the rotation speed of the blade 1 is switched to a low speed, and when the blade 1 reaches the point P4, the valve 13a is closed and the valve 13b is opened, and the amount of pure water 10 jetted decreases. Then, the chuck table 3 quickly returns to the original position at a speed of 300 mm / min. When the blade 1 reaches the point P5 again, the rotation speed of the blade 1 is switched to high speed. The amount of spout increases. Then, the blade 1 starts cutting into the wafer 11, and when the blade 1 reaches the point P7 of the wafer 11, the rotation of the blade 1 is switched to low speed, and reaches P8, and when the cutting of the wafer 11 by the blade 1 is completed. The amount of pure water 10 ejected from the nozzle 9 is reduced by switching the valve.

As described above, the operation set in advance in the program sequencer 8 switches the rotation speed of the blade 1 for each stroke and the amount of the pure water 10 jetted by the valves 13a and 13b in one direction. Complete the disconnect. Next, the chuck table 3 is rotated 90 degrees,
In the same manner as described above, the wafer 1 is caused to travel in the direction perpendicular to the above-mentioned one direction by running the blade 1 by the program incorporated in the program sequencer 8 in the direction perpendicular to the above-mentioned one direction, and cut into dices to form a rectangular shape. The semiconductor circuit element pieces are divided individually.

Here, a trial calculation will be made as to how much pure water can be saved. For example, the traveling speed when cutting the blade is 80 mm / min, and the traveling speed when reversing is 300 mm / m.
Assuming that a 6-inch diameter wafer was moved by a blade in each direction for 14 strokes in one direction and divided into 10-mm square semiconductor circuit element chips, the amount of pure water used was calculated for the conventional case and the present invention. View.

First, in the conventional case, while the blade is running,
A pure water flow of 3.3 l / min is always flowed, one stroke of the blade is set to 170 mm, which is slightly larger than the diameter of the wafer of 6 inches (about 150 mm), and the number of strokes for cutting and dividing is the number of times of reciprocating in one direction and one direction. The total number of reciprocations in the direction perpendicular to the direction is 14 × 4 = 56, and the total travel distance of the blade is 170 × 56 = 9520 m
m. Half of the distance is the distance traveled for cutting, and the other half is simply the distance to return the blade to the original position.

The time required to travel through this total traveling distance is 9520 mm / 2 ／ 80 mm / min + 9520 m
m / 2 ÷ 300 mm / min = 75.3 min.
That is, the amount of pure water consumed to cut and divide a 150 mm diameter wafer is 3.3 l / min × 75.3 m
in = 248.49 l, and the pure water consumption is about 250 liters.

On the other hand, in the present invention, pure water is jetted at a flow rate of 3.3 l / min only in the wafer portion having a circular shape.
70 mm square area to circular wafer diameter 150
As described above, pure water is discharged at a flow rate as small as 1 l / min at a distance where the blade returns to the original position from another area obtained by subtracting the circular area of mm. From this, first, when the traveling distance in a region other than the wafer is obtained, the area ratio between the square and the circle is (1−3.14 / 4) ×
9520 mm = 2046 mm. On the other hand, the traveling distance on the wafer surface is 9520 mm-2046 mm = 7474.
mm. Then, the distance traveled by the blade to return to the original position is 4760 mm as described above.

Next, the consumption of pure water is determined from the running time of these blades. First, pure water is applied on the wafer surface.
The running time while injecting 3 l / min is 7474.
mm / 2 ÷ 80 mm / min = 46.7 min,
The consumption is 46.7 min × 3.3 l / min = 1.
54l. On the other hand, the distance traveled at a flow rate of 1 l / min is 1023 mm, which is half of 2046 mm, in the region other than the wafer surface, and the distance that the blade returns to the original position is 4760 mm. And the running time is (10
23mm + 4760mm) ÷ 300mm / min = 1
9.27 min, the consumption is 19.27 × 1 l /
min = 19.27 l.

Therefore, the consumption of pure water according to the present invention is 1
54 liters + 19.27 liters = 173.27 liters. It can save more than 30% compared to the conventional 250 liters.

[0027]

As described above, according to the present invention, an appropriate flow rate of pure water is sprayed only when a wafer is being cut, and a small amount of pure water is supplied when the wafer is not cut. By providing a program sequencer, the consumption of pure water can be minimized. Also, when not cutting, reduce the injection amount of pure water and reduce the number of revolutions of the blade to prevent scattering of chips and chips, prevent reattachment to the wafer, and maintain cleanliness after cutting and dividing. There is also an effect that can be done.

[Brief description of the drawings]

FIG. 1 is a schematic diagram and a time chart of a dicing apparatus for explaining one embodiment of a dicing apparatus of the present invention.

FIG. 2 is a diagram schematically illustrating an example of a conventional dicing apparatus.

FIG. 3 is a plan view showing the wafer of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Blade 2a, 2b, 2c Flow control part 3 Chuck table 4, 4a Drive mechanism part 5, 5a Control part 6, 6a Rotation drive part 7 Holder 8 Program sequencer 9, 9a Nozzle 10 Pure water 11 Wafer 13a, 13b Valve

Claims (2)

(57) [Claims] 1. A dicing apparatus which cuts and divides a plurality of semiconductor circuit elements arranged and arranged in a matrix on a circular wafer as a semiconductor substrate into individual semiconductor circuit elements by a rotating disk-shaped blade. A rotation drive unit for rotating a blade, a chuck table for holding and moving the wafer, a drive unit for moving the chuck table and relatively moving the wafer and the blade, and a pure drive for the blade and the wafer. Nozzle for injecting water, the jetting amount of the pure water is set to an appropriate amount while the blade is cutting the wafer, and the jetting amount of the pure water is not appropriate when the blade is not cutting the wafer. Control means for setting the amount to be less than an appropriate amount. 2. The dicing apparatus according to claim 1, wherein the rotation speed of the blade when the wafer is not cut is lower than the rotation speed when the wafer is cut.