JP2003117818A - Method and device for grinding substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for grinding a substrate capable of preventing the substrate from being broken by solving such a problem with a substrate having a diameter of as large as 300 mm or more that grinding waste penetrates into a clearance between a film and a device pattern face together with grinding fluid and the substrate is broken. SOLUTION: When the rear surface of the substrate is ground by slidably moving a cup wheel type grinding wheel on the surface of the substrate by using a grinding device having the cup wheel type grinding wheel 50 and a grinding fluid feeding mechanism 59, fluid adhered to the blade tip 55 of the cup wheel type grinding wheel apart from the surface of the substrate is removed by allowing the blade tip 55 to pass through the inside of the groove of a fluid cutting board 90 installed on the outside of a chuck 4. Since the grinding fluid adhered to the blade tip is removed by the fluid cutting board 90, the possibility of presence of the grinding waste between the film and the device pattern face in a grinding system can be eliminated to prevent the substrate from being broken.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a silicon wafer,
The present invention relates to a surface grinding apparatus suitable for grinding a semiconductor substrate such as a germanium wafer, an aluminum wafer, and a glass substrate, and a method for grinding the surface of a semiconductor substrate.

2. Description of the Related Art For grinding a semiconductor substrate, a surface grinding machine having a substrate chuck mechanism, a cup wheel type grindstone supported by a spindle, and a grinding liquid supply mechanism is used (Japanese Patent Laid-Open No. 2-274462). Same as 3-154773
No. 11-254318, JP-A-2000-9434.
No. 2).

An example of such a surface grinding apparatus is a surface grinding apparatus shown in FIG.
-254318). In the figure, 1 is a surface grinding machine, A
Is a main body base, 2 is a rotation axis, 3 is a wafer (substrate), 4 is a chuck, 5 is a cup wheel type grindstone, 6 is a body casing, 7 is a lifting device, 8 is a spindle, 9 is a bearing, and 10 is a bearing. Is a spindle casing, 11 is a head for mounting a cup wheel type grindstone, 12 is a mounting member for mounting the spindle casing on an elevating mechanism, 13 is a motor for driving a tilt adjusting bolt described later, and 14 is a spindle shaft. A built-in motor driven to rotate, 15 is an X-axis tilt adjustment bolt, 15a is a disc spring, 15 'is a Y-axis tilt adjustment bolt, and 16 is a vertical movement device. A rail having a concave groove, 18 is a hemispherical convex portion provided on the spindle shaft casing, and 19 is formed so that it can be fitted on the front surface of the elevating device with a slight gap with the hemispherical convex portion. Hemispherical recess, 1 rod, 22 is an air bearing.

A spindle 8 is lowered by an elevating device onto the surface of the wafer 3 placed on the grinding table 4 to press a cup wheel type grindstone against the wafer surface, and both spindle shafts 2 and 8 are moved in the same direction or in the reverse direction. The wafer is ground by sliding a grindstone on the wafer surface by rotating the wafer in the direction.

As the cup wheel type grindstone 5, an annular peripheral wall 5a shown in FIG. 7 and a bottom wall 5b provided at one end thereof.
A fan-shaped grindstone piece (blade edge) 5d is annularly formed on the upper surface of the cup-shaped base metal opposite to the bottom wall of the cup-shaped base metal with an adhesive so that a grinding fluid flows between the grindstone pieces 5d and 5d. Cup wheel type grinding wheel fixed so as to form 5f (No. 61-144959, No. 61-144)
961, 61-149,962, JP-A-62-18
1875). The grindstone pieces are
Height 3-7mm, width 3-10mm, length 3-7m
It is generally an annular fan of m.

Further, as disclosed in Japanese Patent Application Laid-Open No. 2000-94342, a surface of a cup-shaped base metal having an annular peripheral wall and a bottom wall provided at one end of the cup-shaped base metal is opposite to the bottom wall of the peripheral wall. Is a cup-wheel type grindstone in which an annular grindstone is fixed to the upper surface of the base metal, and the base metal includes an annular groove (a) provided concentrically with the peripheral wall on the outer surface of the bottom wall and a grinding liquid supplied into the annular groove. It is provided so as to penetrate the bottom wall from the bottom surface of the annular groove so as to be introduced into the inner side of the peripheral wall, is inclined toward the outer peripheral side toward the other end side of the peripheral wall, and is equidistant from the peripheral wall at many equal intervals. An annular grindstone having a grinding fluid introduction hole (b) provided and fixed to the upper surface of the peripheral wall opposite to the bottom wall is a shaft shared by the peripheral wall and the annular groove in a portion protruding from the top surface of the peripheral wall. With respect to the upright surface of the circular grindstone that is orthogonal to the axis and the axis, face the outer side of the wheel from the axis side. 30 to 60 degrees inclined grinding liquid discharge slit (c) is provided in a number equal intervals Kappuhoi - and Le grinding wheel also be used.

In this cup wheel type grindstone, the height of the slit is 3 to 10 mm, the grindstone width is 2 to 7 mm,
Length of grindstone blade divided by slit is 10-50mm
Is. The diameter of the grinding fluid introduction hole is 2 to 6 mm, and the peripheral wall height is 2
It is 5 to 45 mm.

The grinding machine shown in FIG. 5 shows a grindstone head structure of a grinding machine 1 equipped with the latter cup wheel type grindstone.

In the head structure of the surface grinding apparatus shown in FIG. 5, 6 is a main body casing, 8 is a spindle shaft, 9 is a bearing, 11 is a cup wheel type grindstone mounting plate, and 12 is a spindle shaft casing mounting. Reference numeral 13 is a motor for driving the tilt adjusting bolt, 14 is a build-in motor for rotationally driving the spindle shaft, 22 is an air bearing, 23 is an air supply pipe, 24 is a mounting plate 11 and a spindle shaft. A connecting shaft with a fixed plate 25 for supporting the spindle shaft 26 is a spindle shaft casing 10.
A cooling liquid supply pipe 27 is a head H composed of an air bearing 22 and a surrounding plate (grinding wheel cover) 28 provided below the peripheral wall of the air bearing 22.
A space provided inside, 50 is a cup wheel type grindstone,
51 is a peripheral wall, 52 is a bottom wall, 53 is a cup-shaped base metal, 55 is a grindstone, 56 is an annular groove, 57 is a grinding liquid introduction hole, 59 is a grinding liquid supply nozzle, 60 is a grinding liquid supply pipe, and 61 is a grinding liquid. Although not shown, this grinding fluid supply pipe is an intake port, is fixed to a mounting member of the lifting mechanism, and is connected to the grinding fluid tank by a flexible hose.

The cup wheel type grindstone 50 transmits the rotational drive of the build-in motor 14 through the spindle shaft 8, the fixed plate 25, the connecting shaft 24, and the mounting plate 11 to rotate it. Since the head is fixed to the mounting member 12, the grindstone 5
Even if 0 rotates, the head confidence does not rotate. Therefore, the flexible hose connecting the grinding fluid supply nozzle 59 and the grinding fluid supply tank is not twisted and damaged. The grinding fluid supplied from the grinding fluid supply nozzle 59 to the annular groove 56 of the grindstone 50 is guided to the inner surface 56 of the grindstone circumferential wall through the introduction holes 57, 57, and further passes through the slit 50f and is discharged to the outer side of the grindstone circumferential wall. To be done.

The diameter r of the blade edge group 55 of the cup wheel type grindstone 50 is 4/3 to 2 times larger than the radius of the substrate, and the spindle is set so that the blade edge of the cup wheel type grindstone passes substantially the center point of the substrate. Rotate 8. To grind the substrate, while rotating the substrate held by the chuck 4 in the horizontal direction and supplying a grinding liquid to the surface of the substrate, the blade edge 55 of the cup wheel type grindstone moves the substantially central point o of the substrate. The spindle is rotated so as to pass, and the cup wheel type grindstone is slid on the substrate surface to grind the substrate surface.

As shown in FIG. 4, the diameter is 300 mm, 4
00 mm, the device pattern 3a is provided on the front surface, and the back surface grinding of the semiconductor substrate having the dicer cut groove 3b provided on the device pattern is performed by protecting the surface of the device pattern with a protective film (adhesive tape) 80. With the protective film 80 in contact with the chuck surface, and the back surface 3c of the substrate.
The semiconductor substrate 3 is placed on the chuck 4 so as to face the cup wheel type grindstone 55 (5), and the back surface of the substrate is ground by the cup wheel type grindstone.

[0012]

There was no problem in grinding bare silicon or in a semiconductor substrate having a diameter of 200 mm or less, but in a semiconductor substrate having a substrate diameter of 300 mm or more, the protective film 80 and semiconductor The grinding fluid containing grinding dust enters between the device patterns 3a of the substrate 3,
It has been found that a phenomenon in which the semiconductor chips 3 are broken due to the grinding dust working badly during the back surface grinding or during the transportation of the substrate after grinding rarely occurs.

The cause of this crack is that the end portion (edge portion) 3d of the semiconductor substrate has a rounded sharp point, and the end portion of the protective film 80 during grinding is the device pattern 3 of the substrate.
When peeled from the surface a, the grinding liquid containing grinding dust penetrates between the protective film 80 and the device pattern 3a of the semiconductor substrate 3, and the grinding liquid penetrates through the dicer groove 3b. When remaining in the dicer groove 3b of the device pattern, the pressure applied to the semiconductor substrate from the head H concentrates on the grinding dust, and external stress acts on the dicer groove 3b portion of the substrate, which is weak in strength. It seems that this will lead to cracking.

It is an object of the present invention to provide a substrate grinding method and a grinding apparatus used therefor, which do not cause such cracking of the substrate even in the case of backside grinding of a semiconductor substrate having a large diameter.

[0015]

According to a first aspect of the present invention, there is provided a chuck for holding a substrate, a cup wheel type grindstone having a diameter larger than a radius of the substrate supported by a spindle, and a grinding fluid supply mechanism. Using a grinding device provided, while rotating the substrate held by the chuck in the horizontal direction, while supplying the grinding liquid to the substrate surface, the blade edge of the cup wheel type grinding stone passes the substantially central point of the substrate. In the method of grinding the substrate surface by rotating the spindle in such a manner that the cup wheel type grinding stone slides on the substrate surface, the cutting edge of the cup wheel type grinding stone separated from the substrate surface is provided outside the chuck. The present invention provides a method for grinding a substrate, which is characterized in that the liquid adhering to the blade edge is removed by passing through the groove.

When the cutting edge of the cup wheel type grindstone passes through the groove of the liquid cutting weir, the liquid such as the grinding liquid adhering to the cutting edge rotating at a high speed is a gap between the groove of the liquid cutting weir and the cutting edge. Since it is drained, the grinding dust contained in the grinding fluid comes into contact with the liquid cutting weir and is blown away, so when the blade tip returns to the grinding system, no grinding dust is attached to the blade tip. .
Therefore, the opportunity for grinding dust to penetrate between the protective film 80 and the device pattern 3a of the semiconductor substrate 3 is lost, so that the semiconductor substrate 3 is not cracked.

According to a second aspect of the present invention, in the method for grinding a substrate described above, the groove of the liquid draining weir has a side wall of the groove of 10 to 1000 μm from a side surface of a cutting edge of a cup wheel type grinding stone, and a bottom of the groove has a cutting edge. It is characterized in that it is 10 to 1000 μm away from the lower surface of the.

Considering the surface tension of the liquid and the number of rotations of the cup wheel type grindstone, this is the gap distance between the groove and the cutting edge where the grinding dust does not pass through the groove of the liquid cutting weir.

According to a third aspect of the present invention, a chuck for holding a substrate, a rotating mechanism of the chuck, a cup wheel type grindstone having a diameter larger than a radius of a substrate supported by a spindle, a rotating mechanism of the spindle, and a lifting mechanism. A grinding device provided with a mechanism, a grinding liquid supply mechanism, and a liquid cutting weir for removing the liquid adhering to the blade edge of a cup wheel type grindstone.

Since the cup wheel type grindstone having a diameter larger than the radius of the substrate supported by the spindle is used, the liquid draining weir can be provided outside the chuck.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below with reference to the drawings. FIG. 1 is a partial front view of a grinding device in which a liquid cutting weir is provided in a support member provided in a grindstone cover, and FIG.
FIG. 3 is a perspective view of a liquid cutting weir, and FIG. 3 is a perspective view showing the relative relationship among the blade tip rotation direction of the cup wheel type grinding stone of the grinding device, the substrate rotation direction, the grinding liquid supply position, and the position of the liquid cutting weir. Four
Is a semiconductor substrate mounted on the chuck and a cup wheel.
It is a partial front view which shows the positional relationship of a grinding wheel, a liquid cutting weir, and a grinding fluid supply mechanism.

Cup-wheel type grindstone: The cup-wheel type grindstone is the same as the above-mentioned No. 61-144959, Ukaikai Sho 61-149959.
No. 144961, No. 61-144962, JP-A-62.
Known cup wheel type grindstones can be used, including the cup wheel type grindstones described in JP-A-181875 and JP-A-2000-94342. The cup wheel type grindstone is available from Okamoto Machine Tool Co., Ltd., Asahi Diamond Co., Ltd., and Mitsubishi Materials Co., Ltd.

The blade edge 55 of the cup wheel type grindstone is formed by molding diamond abrasive grains and CBN abrasive grains into an annular fan with an adhesive such as phenol resin or epoxy resin. As for the dimensions of the annular fan body (grinding blade tip) 55, the height is generally 3 to 7 mm, the width is 3 to 10 mm, and the length of the grindstone blade divided by the slit is 10 to 50 mm. The slit width is 1 to 3 mm. The diameter formed by the blade group 55 of the cup wheel type grinding stone is 4/3 of the radius of the substrate to be ground.
2.2 times, preferably 2 times. Cup hoo
Since the cup wheel type grinding stone is slid on the substrate surface to grind the substrate surface by rotating the spindle so that the blade edge of the grinding wheel passes the substantially central point of the substrate, the liquid cutting weir 90 Can be provided outside the chuck 4 (FIG. 1,
See FIG. 2).

Grinding device: The grinding device is not limited to the grinding device shown in FIG. 5, but a commercially available back surface grinding device, for example, GNX (trade name) series manufactured by Okamoto Machine Tool Co., Ltd.
GNX-P (trade name) series (JP-A-11-3074)
No. 89, Tokyo Seimitsu Co., Ltd. PG (trade name) series can also be used. In the grindstone cover 28 of these backside grinding devices,
As shown in FIG. 1, a support member 91 is provided, and the liquid draining weir 90 is fixed to the support member with bolts 92. Whetstone cover-28
It is preferable that one of the members is slidably provided so that the wear state of the cutting edge 55 of the cup wheel type grindstone 50 can be observed.

As shown in FIG. 3, the liquid draining weir 90 has a groove 90a having a concave cross section. The size of this groove is such that the side wall of the groove is 10 to 1000 .mu.m from the side surface of the cutting edge of the cup wheel type grindstone.
m, preferably 30 to 100 μm, the bottom of the groove is 10 to 1000 μm from the lower surface of the cutting edge, preferably 30 to 600 μm
The distance is m. The groove width w of the liquid cutting weir 90 is 10 to 3
0 mm is sufficient.

Examples of the material for the liquid draining weir 90 include resin moldings such as ceramic unglazed, poly (tetrafluoroethylene), poly (dichlorodifluoroethylene), and polyacetal.

The attachment position of the liquid cutting weir 90 is a position outside the chuck near a position where the blade edge of the cup wheel type grindstone grinds the substrate and moves away from the chuck, and is a position far from the grinding liquid supply position.

For backside grinding of the substrate, the hollow spindle 2 bearing the porous ceramic chuck 4 is depressurized with the backside of the substrate 3 facing upward to hold the substrate on the chuck 4, and the hollow spindle 2 is horizontally moved by the motor 2a. By rotating the substrate held by the chuck 2 in the horizontal direction by supplying the grinding fluid 1 to 15 liters / minute to the surface of the substrate from the grinding fluid supply pipe 59, the cup wheel type grindstone 50 is rotated. The spindle 8 is rotated so that the blade edge 55 of the grindstone passes through the substantially center point of the substrate, and the cup wheel type grindstone is slid on the substrate surface to grind the substrate surface. In addition,
The grinding liquid may be supplied onto the substrate 3 via the annular groove 56 of the grindstone 50 as shown in FIG. 5, or may be supplied directly onto the substrate as shown in FIG.

The number of revolutions of the hollow spindle 2 is 30 to 30.
0 rpm, the rotation speed of the spindle 8 is 1000 to 4000
rpm.

[0030]

Example 1 A semiconductor substrate having a thickness of about 700 μm and a diameter of 300
20 mm long and 20 mm wide on the surface of a silicon wafer of mm
A device having a device pattern in which a plurality of square device patterns are divided into a grid pattern with a dicer width of 200 μm and a dicer groove depth of 10 μm and a protective film is attached to the device pattern surface. I was there.

As the backside grinding machine, a grinding machine in which a ceramic liquid draining weir made of alumina particle biscuit is fixed with bolts to a support member attached to a grindstone cover of a backside grinding machine GNX300 (trade name) manufactured by Okamoto Machine Tool Co., Ltd. Using. The size of the arc-shaped groove of the liquid cutting weir is 100 μm from the side surface of the cutting edge of the cup wheel type grinding stone when the back surface is initially ground.
m, the bottom of the groove is 200 μm away from the lower surface of the cutting edge, and the arcuate groove width is 15 mm. The margin of the back surface silicon layer of the semiconductor substrate was set to 100 μm.

The semiconductor substrate is covered with the protective film.
The semiconductor substrate was placed on the chuck so as to abut the lath ceramic chuck surface, and the hollow spindle was depressurized to fix the semiconductor substrate to the chuck. Next, the semiconductor substrate is horizontally rotated by rotating the hollow spindle at 100 rpm, and the spindle supporting the cup wheel type grinding wheel with a diameter of 300 mm is rotated at 3000 rpm while being lowered to make the blade edge of the cup wheel type grinding wheel. Is brought into contact with the silicon substrate of the semiconductor substrate at a position where it passes the center point of the semiconductor substrate, and 6 liters / liter of grinding liquid is applied to the surface of the semiconductor substrate.
The back surface of the substrate was ground while the liquid adhering to the blade was cut off by the liquid cutting weir while being supplied at a rate of min.

When the back surface grinding for peeling off the silicon layer of about 100 μm thickness is completed, the spindle is raised and the cup wheel is moved.
The grinding wheel was moved away from the surface of the semiconductor substrate, and then rotation and depressurization of the hollow spindle were stopped, and compressed air was supplied to the hollow spindle to facilitate the chuck separation of the semiconductor substrate.

The semiconductor substrate on the chuck was adsorbed to the transfer pad, transferred to the cleaning mechanism, spin-cleaned and spin-dried by the cleaning mechanism, and then the back-ground semiconductor substrate was transferred into the storage cassette by the transfer robot.

The backside grinding of 200 semiconductor substrates was continuously performed in the same manner, but none of the semiconductor substrates was damaged.

[0036]

EFFECTS OF THE INVENTION The grinding device provided with the liquid cutting dam of the present invention is
When back grinding a semiconductor substrate using a cup wheel type grindstone, even if the grinding fluid containing grinding dust generated by the back side grinding adheres to the blade edge of the cup wheel type grindstone, when the blade edge returns to the grinding system again. Since the grinding dust adhering to the blade edge is removed by the liquid cutting weir, the opportunity for the grinding dust to penetrate between the protective film and the device pattern surface of the substrate is lost.
The semiconductor substrate will not be damaged during grinding or substrate transfer.

[Brief description of drawings]

FIG. 1 is a partial front view of a grinding apparatus in which a support member provided on a grindstone cover is provided with a liquid cutting dam.

FIG. 2 is a plan view showing a relative relationship among a rotation direction of a cutting edge of a cup wheel type grindstone of a grinding device, a rotation direction of a substrate, a grinding liquid supply position, and a position of a liquid cutting weir.

FIG. 3 is a perspective view of a liquid draining weir.

FIG. 4 is a partial front view showing a positional relationship among a semiconductor substrate mounted on a chuck, a cup wheel type grindstone, a liquid cutting dam, and a grinding liquid supply mechanism.

FIG. 5 is a front view showing a head portion of a backside grinding device. (Public)

FIG. 6 is a front view of a backside grinding device. (Public)

FIG. 7 is a perspective view of a cup wheel type grindstone. (Public)

[Explanation of symbols]

1 grinding machine 2 hollow spindle 3 substrates 3a Device pattern 3b Dicer groove 4 chuck 5,50 cup wheel type grindstone 55 cutting edge 8 spindles 14 Built-in Motor 28 Whetstone cover 59 Grinding liquid supply nozzle 80 Protective film 90 draining weir 91 Mounting member

Claims (3)

[Claims] 1. A chuck for holding a substrate, a cup wheel type grindstone having a diameter larger than the radius of the substrate supported by a spindle, and a grinding apparatus equipped with a grinding fluid supply mechanism are used to hold the chuck. While rotating the substrate in the horizontal direction, while supplying the grinding liquid to the substrate surface, the cup wheel type grindstone is rotated by rotating the spindle so that the blade edge of the grindstone passes through the substantially central point of the substrate. In the method of grinding the substrate surface by sliding on the substrate surface, the blade tip of the cup wheel type grindstone distant from the substrate surface is passed through the groove of the liquid cutting weir provided outside the chuck, and the liquid adhered to the blade tip. A method for grinding a substrate, characterized in that 2. The size of the groove of the liquid draining weir is such that the side wall of the groove is 10 to 1000 μm away from the side surface of the cutting edge of the cup wheel type grindstone, and the bottom of the groove is apart from 10 to 1000 μm from the lower surface of the cutting edge. The method for grinding a substrate according to claim 1, wherein the method is for grinding a substrate. 3. A chuck for holding a substrate, a rotating mechanism for the chuck, a cup wheel type grindstone having a diameter larger than a radius of a substrate supported by a spindle, a rotating mechanism for the spindle, a lifting mechanism, and a grinding fluid supply mechanism. , And a grinding device equipped with a liquid cutting weir for removing the liquid adhering to the blade of the cup wheel type grindstone.