JP3217731B2 - Wafer processing method and double-sided surface grinder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing method for ultra-precise and parallel grinding of both surfaces of a hard thin wafer used for a semiconductor and a double-sided surface grinding machine used in the processing method. is there.

[0002]

A wafer cut from an ingot is rough in both surface roughness and shape accuracy. Therefore, when lapping is performed on a wafer that has been cut from an ingot, it takes a very long time and processing efficiency is not good. Also, in single-side grinding of a wafer, the shape of the wafer after one-side grinding from the ingot is flat during suction because the vacuum chuck chucks one side of the work, but the shape returns to its original shape when the work is removed from the vacuum chuck. There is a tendency.

According to the processing of a wafer by grinding which is attempted to improve the processing efficiency and the processing accuracy by the above-described lapping, required surface accuracy can be obtained in a short processing time. However, as long as the chucking of the wafer is performed by a vacuum chuck, the shape accuracy cannot be obtained.

The present invention is a further development of the prior art described below, and aims to provide a wafer processing method capable of obtaining surface accuracy and shape accuracy in a short time and a double-sided surface grinding machine used in the processing method. Aim.

[0005]

According to a first aspect of the present invention, there is provided a method of processing a wafer after cutting from an ingot.
A work supporting member that holds the wafer and rotates the wafer,
A double-sided surface grinder that has a pair of whetstones and grinds the wafer at the whetstone end faces with the two whetstone end faces facing each other, and the wafer surface protruding from the whetstone outer peripheral side of the contact part between the wafer and the whetstone end face to only one side of the wafer Prepare a work rest that holds the wafer immediatly and immovably by acting on the gas, rotate the wafer with the work support member, hold the wafer from only one side with the work rest, and grind the center of the wafer with a grindstone This is a wafer processing method characterized in that grinding is performed by applying a grindstone to both surfaces of a wafer so that the surface passes through.

According to a second aspect of the present invention, there is provided a double-headed surface grinding machine in which a pair of grindstones are disposed with both grindstone end faces facing each other, and a disc-shaped work is machined with the grindstone end faces. A work supporting member for rotating the work at a center parallel to the grindstone axis, a grindstone, and a gas that acts on only one side of the work by applying a gas to the work surface protruding from the grindstone when the grindstone is applied to the work surface. And a work rest for holding the workpiece immediately and inseparably.

A third invention according to the present application is characterized in that a hydrostatic slide is provided by providing a gas intake orifice and a gas discharge orifice in the work rest between the work rest and the work surface. 2 is a double-sided surface grinding machine according to the invention. A fourth invention according to the present application is the double-sided surface grinder according to the third invention, wherein a plurality of discharge orifices are provided around the suction orifice.

[0008]

2. Description of the Related Art Wafers such as silicon wafers are obtained by cutting an ingot with an inner saw or a wire saw and then finishing the polishing with a lapping machine.

On the other hand, finishing a wafer by grinding is disclosed, for example, in Japanese Utility Model Publication No. 3028734, Machine and Tool, 1995.
July to July, pages 60 to 64, Journal of the Japan Society of Abrasive Technology Vo
l. 39 No. 4 1995. JUL. It is disclosed on pages 20 to 23 and the like.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to FIGS.

(Embodiment 1) As shown in FIGS. 1 to 4, the double-sided surface grinding machine of this embodiment includes a lower frame 11, and the lower frame 11
An upper frame 111 is fixed above. The lower frame 11 is provided with a lower grindstone rotating / elevating mechanism 12 and a work supporting member 14, and the upper frame 111 is equipped with an upper grindstone rotating / elevating mechanism 13. Upper and lower rotary grindstones 15 and 16 are disposed on the two grindstone rotary elevating mechanisms 12 and 13, respectively, and the upper or lower end surfaces of the rotary grindstones 15 and 16 are opposed to each other so that the grinding surfaces 15a and 16a are parallel to each other. Are located. Then, in a state where the thin plate-shaped work 17 is supported by the work support member 14, the work 17 is inserted between the rotary grindstones 15 and 16 of the two grindstone rotary elevating mechanisms 12 and 13, and the grinding action surfaces of the rotary grindstones 15 and 16 are arranged. 15a,
16a allows both surfaces of the work 17 to be ground simultaneously.

As shown in FIGS. 2 and 3, the grinding wheel base 20 of the lower grinding wheel rotating and lifting mechanism 12 is mounted on the lower frame 11 via a so-called V-flat guide 21 through the lower rotating grinding wheel 15.
Are supported so as to be movable in a direction perpendicular to the rotation axis of the rotator. The lower wheel head moving motor 22 is disposed on the side of the lower frame 11, and the rotation of the motor 22 causes the wheel head 20 to move horizontally through a ball screw 23 screwed into a ball nut 23 a fixed to the wheel head 20. Move laterally. The lower shaft support 24 is supported so as to be able to move up and down in the rotation axis direction of the lower rotary grindstone 15 via a vertical guide 24 a provided integrally with the grindstone table 20. The lower grindstone head elevating motor 25 is provided with a guide portion 24 at a lower portion of the grindstone head 20.
a rotation transmitting mechanism 2, which is provided on the side of
The lower shaft support 24 is moved up and down by being guided by the guide portion 24a via a ball screw 27 screwed into a ball nut (not shown) fixed to the bracket 6 and the bracket 24b fixed to the lower shaft support 24. This elevating stroke is slight.

The lower grindstone shaft 28 is rotatably supported in the lower shaft support 24, and the lower rotating grindstone 15 is mounted via a grindstone holder 29 integrally formed on the upper end thereof.

A grinding wheel drive motor 34 is disposed inside the lower shaft support 24, and its stator is fitted and fixed to the lower shaft support 24, and its rotor is fitted and fixed to the lower grind shaft 28, and is used for grinding. The rotation of the motor 34 causes the lower rotating grindstone 15 to rotate at a high speed via the lower grinding wheel shaft 28.

As shown in FIG. 3, the upper shaft support cylinder 38 of the upper grindstone rotating / elevating mechanism 13 is supported via a guide 39 integral with the upper frame 111 so as to be able to move up and down in the rotational axis direction of the lower grindstone 16. ing. The elevating motor 40 is disposed on the side of the upper frame 111, and the rotation of the motor 40 causes the bracket 3 fixed to the upper shaft support 38.
The upper shaft support cylinder 38 is moved up and down via a ball screw 41 screwed into a ball nut 41a fitted and fixed to 8a.

The upper grinding wheel shaft 42 is rotatably supported in the upper shaft support cylinder 38, and the upper rotating wheel 16 is mounted on the lower end thereof via a grinding wheel holder 43 formed integrally. A grindstone drive motor 48 is disposed inside the upper shaft support 38, and its stator is fitted and fixed to the upper shaft support 38, and its rotor is fitted and fixed to the upper grindstone shaft 42 and rotates the motor 48 during grinding. Thereby, the upper rotating grindstone 16 rotates at a high speed via the upper grindstone shaft 42.

As shown in FIGS. 2 and 4, the support table 52 of the work support member 14 has upper and lower grinding wheels
It is disposed on the lower frame 11 between 2 and 13. The slide table 53 is supported by a pair of guide rails 54 disposed on both sides of the lower rotary grindstone 15 on the support table 52 so as to be movable in the same direction as the moving direction of the grindstone table 20 of the lower grindstone rotary elevating mechanism 12. Have been. As shown in FIG. 4, the slide table moving motor 55 is
The ball screw 56 connected to the motor shaft of the motor 55 is screwed into a ball nut 56a fixed to the slide table 53 by the rotation of the motor 55, so that the slide table 53 can be moved. ing.

An annular rotating plate 57 is disposed in the slide table 53 and rotatably supported via three guide rollers 58 rotatably supported by the slide table 53 (see FIG. 5). . The rotating plate 57 has a work supporting plate 60 mounted on an annular thick outer peripheral frame 57a.
A gear 59 is formed on a lower outer periphery of the outer peripheral frame 57a. The work support plate 60 is formed thinner than the work 17,
The lower surface of the outer peripheral frame 57a is horizontally stretched via a tension mechanism (not shown) so as not to be bent and deformed by the gravity, and a set hole 60a for setting the work 17 in a detachable manner is formed at the center thereof. I have. This set hole 6
0a has a diameter at which the work 17 is loosely fitted. A rotating plate rotating motor 61 is provided on a slide table 53, and a gear 62 that meshes with a gear 59 of a rotating plate 57 is fixed to a motor shaft of the motor 61. Then, by the rotation of the motor 61, the rotating plate 57 is
Rotates. The inner diameter of the outer peripheral frame 57 a has a diameter such that the upper rotary grindstone 16 descending offset with respect to the rotary plate 57 can approach the work supporting plate 60.

As shown in FIG. 4, a notch or an orientation flat (orientation flat) serving as a reference for the crystal orientation of a workpiece 17 which is an unground wafer which has been cut from an ingot is formed in a set hole 60a of the workpiece support plate 60. A work drive unit 60b protruding toward the inner peripheral side so as to engage with the portion 17a is provided. Notch 1 of this work 17
The shape of 7a is a shape having a V-groove-shaped notch as in the present embodiment or an orientation flat that cuts a circular arc on the outer periphery of the work as an edge, and the driving portion 60b is a shape that substantially complements the cutout portion 17a of the work. However, the notch 1 of the work 17
7a may be separately provided on the work 17 in order to drive the work 17 at a position other than the position for knowing the crystal orientation.

Although the work set hole 60a is a circle in this example, the work set hole 60a is not limited to a circle and may have any shape so that the position of the work 17 can be determined. 17 may be in contact with the outer periphery.

Next, the operation of the double-sided surface grinder configured as described above will be described.

In the case of performing grinding in the double-sided surface grinder, the work 17 is not supported by the work supporting member 14.
The upper and lower rotary grindstones 15 and 16 are inserted and disposed between the upper and lower rotary grindstones 15 and 16 while the upper and lower grindstone rotary elevating mechanisms 12 and 13 are loosely fitted to the work support plate 60. In this state, the upper and lower rotary grindstones 15, 16 are rotated at a high speed while the upper and lower grindstone rotary elevating mechanisms 12, 13 are rotated at a high speed, the rotary plate rotating motor 61 is driven to rotate at a low speed, and the work supporting plate 60 serves as a rotary drive means. Gear 6
The work 17 held by the set holes 60a is rotated through the rotation of the workpieces 2 and 59. Then, the upper rotary grindstone 16 of the upper grindstone rotary elevating mechanism 13 descends and approaches the work 17, and the grinding action surfaces 15 a,
Both surfaces of the work 17 are simultaneously ground by 16a.

FIG. 7 is a front view showing a grinding operation surface of the grinding tool, and FIG. 8 is a longitudinal sectional view of the grinding tool including the center of FIG. In the present embodiment, the same members are used for the rotating grindstones (grinding tools) 15 and 16 described above. Here, the whole of the grinding tool is represented by reference numeral 1.

The grinding tool 1 is provided with a diamond grindstone 3 as a rotary grindstone slightly smaller than the diameter of the baseplate 2 and concentric with the grindstone shaft on the end face of the baseplate 2 made of an iron disk. The diamond grindstone 3 is arranged in an annular shape with a width.

The diamond grindstone 3 is obtained by hardening diamond abrasive grains with a binder and fixing it to the base plate 2.

The grinding surface 3a of the diamond wheel 3 is on the same plane perpendicular to the wheel axis. A cylindrical concave fitting portion 2a is fitted on the rear surface of the base plate 2 to a convex fitting portion 6a of a grindstone holder 6 having the same diameter as the base plate 2 (used in place of the reference numerals 29 and 43). Then, the back surface of the base plate 2 and the front surface of the grindstone holder 6 are brought into close contact with each other, and a bolt 7 inserted through a bolt hole of the base plate 2 is screwed into the grindstone holder 6 and fixed.

FIG. 7 shows a diamond grindstone 3 and a work 17.
Dimensions and positional relationship are shown. When the work 17 is set in the work set hole 60a, the work set hole 60a
The center of a and the center of the work 17 coincide. The center 0G of the diamond grindstone 3 is offset from the work center 0W so that the diamond grindstone 3 passes on the work center 0W.
are doing. Assuming that the average diameter centered on 0 G through the bisecting point of the grinding wheel surface 3a in the radial direction of the diamond grinding wheel 3 is called a grinding wheel average diameter, in this example, the grinding wheel average diameter is one half of the diameter of the work 17. Has become. The average diameter of the grindstone is a diameter obtained by subtracting the radial width of the grinding surface 3a from one half of the diameter of the work 17, that is, a range in which the outer diameter of the grindstone of the diamond grindstone 3 is a half of the diameter of the work 17. In theory, it is desirable that the outer diameter of the grindstone is larger than one half of the diameter of the work 17 so that the entire surface of the work 17 can be ground but the work surface that is not ground in practice does not occur.

On the other hand, since the upper grindstone 16 must enter the outer peripheral frame 57a of the rotary plate 57, the average diameter of the grindstone is Dg, the diameter of the grindstone holder (or the base plate 2) 6 is Dp, and the inner diameter of the outer peripheral frame 57a is Is Df, Dg + Dp <Df. Therefore, the work 17 can be ground by the diamond grindstone 3 even if the grindstone diameter Dg is larger than one half of the diameter of the work 17. However, if the diameter Dp of the grindstone holder 6 is large, the diameter of the outer peripheral frame 57 becomes large. . Also, the offset amount e between the workpiece center 0W and the grinding wheel center 0G increases. Accordingly, if the average diameter Dg of the grindstone is set to approximately one half of the diameter of the work 17, it is effective to reduce the size of the device around the grindstone.

As shown in FIGS. 2 and 7, upper and lower work rests 71, 7 for holding both surfaces of the work 17 protruding from the outer peripheral side of the grindstone at the contact surface between the work 7 and the upper and lower grindstones 15, 16 are shown.
2 are provided. The lower work rest 71 is fixed on the lower frame 11 (FIG. 2) or is disposed on an arm 74 fixed to the vertical output shaft 73a of a hydraulically operated rotary actuator 73 fixed to the lower frame 11. (FIG. 7).

As shown in FIG. 17 which is an enlarged view of a part of FIG.
Distance piece 76 on base 75 fixed on top
A lower hydrostatic slide 77 is provided via. FIG.
As shown in FIG.
Reference numeral 7a designates a straight line connecting the rotating plate center 0W and the grinding wheel center 0G as a symmetrical line with a small gap so as to face the surface of the work 17 protruding from the contact portion between the grinding tool 1 and the work 17 on both sides of this diameter. Has been established. Lower hydrostatic slide 7
A pocket (not shown) is provided on the slide surface 77a of the slide 7 and a passage for a gas adopted as a pressure fluid supplied toward the pocket is provided. However, since the static pressure fluid film is formed even without the pocket, the case without the pocket can be adopted. That is, the pressure fluid inlet 7 of the base 75
5a, a fluid passage 75b, a fluid passage 77b of a lower hydrostatic slide 77 fitted into the base 75 via a sealing ring 78, and a space between the fluid passage 77b and a pocket (not shown) provided on the slide surface 77a. The communicating orifice 77c is provided continuously, and gas supplied from the pressure fluid inlet 75a flows between the slide surface 77a of the lower hydrostatic slide 77 and the opposing surface of the lower surface of the work 17.
The gas supplied to the slide surface 77a and the lower surface of the work 17 flows back from the reflux port of the slide surface 77a facing the lower surface of the work 17 outside the pocket (not shown). It should be noted that the work 17 and the slide surface 77 are removed by eliminating this recirculation port.
The gas supplied between the workpiece a and the slide surface 77a
A hybrid fluid pressure slide that uses static pressure and dynamic pressure to flow out to the external space from the gap between them may be used.

The upper work rest 72 has an upper hydrostatic slide main body 81, and comprises a cylinder body 79a, a cylinder bush 79b and a cylinder lid 79g, which constitute a hydraulic cylinder 79, in which an upper part integrated with a piston 81e is provided. A hydrostatic slide main body 81 is provided to be vertically movable. The supply of gas to the upper fluid static pressure slide body 81 is performed by a pressure fluid inlet 79c provided in the cylinder body 79a,
The hole 79d of the cylinder bush 79b, the outer peripheral groove 81a of the upper hydrostatic slide main body 81, the fluid passage 81b provided in the upper hydrostatic slide main body 81, the work 17 and the slide surface 81d on the surface of the upper hydrostatic slide main body 81 are formed. The operation is performed through an orifice 81c communicating between the provided pocket and the fluid passage 81b, and the gas supplied to the pocket is recirculated similarly to the lower hydrostatic slide 77. Note that a hybrid fluid pressure slide may be used.

The upper fluid static pressure slide body 81 is controlled by selectively flowing out and in the pressure fluid from the pressure fluid ports 79e and 79f to both sides of the piston 81e, or by not supplying the pressure fluid together. That is, when the pressure fluid flows into the lower cylinder chamber and the upper cylinder chamber is made non-pressurized, the upper hydrostatic slide body 81 rises, and conversely, when the pressure fluid flows into the upper cylinder chamber and the lower cylinder chamber is depressurized, the upper The hydrostatic slide body 81 descends. It is appropriate to control the speed by bleeding off the non-pressure side. When both cylinder chambers are not pressurized, the upper hydrostatic slide main body 81 tends to descend by its own weight.

The upper work rest 72 having the upper hydrostatic slide constructed in this manner is connected to the upper frame 111.
Or fixed to the upper shaft support cylinder 38. Alternatively, it can be made to be able to move up and down by an independent lifting device (not shown). Further, similarly to the lower work rest 71, the arm may be movable along the work 17 by using an arm, and a position where the surface of the work 17 is held and a position where the work 17 is retracted out of the work 17 may be set.

The above-mentioned pressure fluid may be gas or liquid. The gas is compressed air, the fluid is oil, or the like.
A grinding fluid or the like is used. However, as described above, gas is used as the pressurized fluid for the hydrostatic slide of the work rest.

The operation of the above configuration will be described. The slide surface 77a of the lower hydrostatic slide 77 is located at a position where the lower surface of the work 17 is held. The upper hydrostatic slide main body 81 is retracted from a position for holding the upper surface of the work 17. This retreat position needs at least a position where the upper hydrostatic slide body 81 has risen with respect to the cylinder 79. However, if the retreat position is rising together with the upper shaft support 38 as described above, the upper shaft support After lowering the upper grinding wheel 16 by lowering 38, the upper hydrostatic slide main body 81 is set to the lower position with respect to the cylinder 79. The slide table 53 is moved while the upper rotary grindstone 16 is raised, and the center 0W of the work set hole 60a is offset from the center 0G of the grinding tool 1 to be positioned. This offset e is the average radius of the diamond grindstone 3. The workpiece center 0 W must necessarily overlap the diamond grindstone 3. At this point, the lower rotating grindstone 15 is raised to approach the lower surface of the work support plate 60, and the work 17 is moved to the work drive unit 6 in which the notch 17a of the work 17 projects into the work setting hole 60a.
The workpiece 17 is fitted into the workpiece setting hole 60a by being engaged with the workpiece 0b, and is placed on the lower rotating grindstone 15. As a result, the upper and lower surfaces of the work 17 project upward and downward, respectively, from the upper and lower surfaces of the work support plate 60. Here, the upper rotating grindstone 16 descends and approaches the work 17. Then, the slide surface 81d of the upper hydrostatic slide main body 81 moves from the retracted position toward the upper surface of the work 17. At this time, the slide surface 81d is set on the upper surface of the work 17 at a position where the upper hydrostatic slide body 81 does not descend to the lower limit position with respect to the cylinder 79.

Here, gas is supplied to the upper and lower fluid static pressure slides of the upper and lower work rests 71 and 72, respectively.
The portions 17b protruding from the opposing surfaces of the grinding wheels 15 and 16 on both surfaces of 7 are held by upper and lower fluid static pressure slides.
The holding of the work 17 is performed by the lower surface of the work 17 being determined with respect to the slide surface 77 a of the lower hydrostatic slide 77 and the upper hydrostatic slide body 81 being placed on the upper surface of the work 17. In this case, only the own weight of the upper fluid static pressure slide body 81 is directed toward the workpiece 17 so that an appropriate static pressure fluid film is generated between the slide surface 81d of the upper fluid static pressure slide body 81 and the surface of the workpiece 17. Pressurization or pressurization is performed by the cylinder 79. In addition,
As the pressure medium of the cylinder 79, any of gas and liquid can be adopted. When the grinding wheel drive motors 34 and 48 and the rotary plate rotating motor 61 for driving the work are energized, the upper and lower rotating wheels 1
5, 16 and the work 17 rotate. Here, when the upper rotating grindstone 16 is lowered and cut into the work 17, the diamond grindstone 3 grinds both surfaces of the work 17 respectively. At the time of this grinding, the grinding action surface 3a of the diamond grindstone 3 of the work 17
Where is acting (an arc band passing through the center of the work 17)
The part protruding from the whetstone contact surface other than the work rest 7
At 1,72, it is held from both sides.

When the processing of the work 17 is completed, the upper grindstone 16
The upper hydrostatic slide body 81 is raised, and the lower grindstone 15 is raised.
17b of the work 17 protruding from the outer peripheral side
(See FIG. 7) and lift the work 17 into the set hole 60a.
And remove the work 17. As described above, the upper fluid static pressure slide main body 81 is balanced with the load capacity of the static pressure fluid film between the static pressure slide surface 81d and the work 17 by the weight of itself or the pressurization of the cylinder 79, so that the thermal deformation of the machine body or the like is achieved. And the work 17 can always be held accurately.

In the above description, the work 17 has a wafer diameter of 200 mm and a work rotation speed of 10 r. p. m, the outer diameter of the diamond grindstone 3 is 160 m, the inner diameter is 130 mm, and the upper and lower rotating grindstones 15 and 16 are rotated.
0-3000r. p. After grinding with m, TTV 0.3μ
m, the grinding time was 2 minutes.

In the above description, the upper and lower work rests 71,
Although both surfaces of the work 17 are held at 72, only one surface of the work 17 may be held by one of the work rests. Therefore, in the case of holding the work 17 only on one side of the work 17 with the work rest, it is sufficient to provide one of the upper and lower work rests 71 and 72 in the double-sided surface grinder.

(Embodiment 2) FIGS. 9 and 10 show an example of a grinding tool 1 using a diamond impregnated grindstone. On the surface of the base plate 2, a diamond impregnating grindstone 8 is provided in such a manner that a plurality of concentric circles are alternately provided in radial directions in the same direction. The workpiece 17 is ground so that the center of the workpiece 17 is on the outer peripheral side of the grinding tool 1. As in the case of the cup grindstone, the grindstone diameter is slightly larger than half the diameter of the work 17.

(Embodiment 3) If the main purpose is to grind one side of the work 17, the above-mentioned double-headed grinding machine is used to rotate the lower rotating grindstone 15 or not.
The processing may be performed by rotating the grinding wheel gently, or the lower rotating grindstone 15 may be changed to a member that loosens the grinding action on the workpiece 17 or has no grinding action.

(Fourth Embodiment) FIG. 11 shows a fourth embodiment. Since the upper and lower grindstones 15 and 16 are worn by grinding, the upper and lower grindstones 15 and 16 are driven by the wear amount when the wear amount of the upper and lower grindstones 15 and 16 reaches a predetermined constant amount in order to make the work 17 have a constant thickness. Whetstone 1
5,16 forward).

In the figure, a turning shaft 84 parallel to the grindstone shafts 28 and 42 is connected to a rotary drive source and supported. The root of an arm 85 is fixed to the turning shaft 84. Arm 8
The position sensor 86 attached to the tip of the upper and lower wheels 5,
Grinding action surface 1 of whetstones 15, 16 in contact with or in proximity to
The positions of 5a and 16a can be detected. As shown in FIG. 11, a storage device (not shown) in which the upper grinding wheel 15 is mainly raised, and the grinding action surfaces 15 a and 16 a of the unworn grinding wheels 15 and 16 are brought into contact with or close to the position sensor 86 and detected by the position sensor 86. To memorize it. Then, the arm 85 is rotated to move the position sensor 86 to the grindstones 15 and 1.
12 after retreating from the workpiece 6 and grinding the workpiece 17, FIG.
Then, the grindstones 15 and 16 are retracted to the state (1), and the positions of the grinding surfaces 15a and 16a are detected in the same manner as described above. When detecting this position, the amount of wear on the grindstones 15 and 16 is determined by encoders attached to the elevating motors 25 and 40, and the grinding devices 15 and 16 of the worn grindstones 15 and 16 are driven by the control device to drive the grinding work surfaces 15a and 16a. Finish the thickness of No. 17 uniformly. As the position sensor 86, an air micro, a differential truss, an AE sensor or the like is used.

(Fifth Embodiment) FIG. 13 shows a fifth embodiment. The fifth embodiment is characterized in that the lower work rest 71 is supported, and the other configuration is the same as that of the first embodiment.

A disk 91 concentric with the grinding wheel shaft 28 is fixed to the lower grinding wheel stand 20. A radial bearing 92 is fixed to the disc 91 concentrically. A hydrostatic slide 93 is provided so as to sandwich the outer periphery of the disk 91 from above and below, and the upper and lower surfaces of the disk 91 support the hydrostatic slide 93. The hydrostatic slide 93 has an annular upper slide 93a and a lower slide 93b fixed to each other via a distance piece 93c. Upper slide 93
“a” is rotatably fitted to the radial bearing 92.

The hydrostatic slide 93 serves as an annular table, and a lower hydrostatic slide, that is, a lower work rest 71 is formed on the upper slide 93a of the annular table. A part of the gas supply path to the lower hydrostatic slide is provided in the upper slide 93a. The hydrostatic slide 93 is rotated by a driving device (not shown), but the rotation angle is within 90 degrees. The supply of gas to the hydrostatic slide 93 is performed using a flexible tube (not shown).

In the state shown in FIG.
Reference numerals 1 and 72 are at opposing positions, and hold the work 17 and grind the work 17 with the grindstones 15 and 16. When the work 17 is detached from the machine, if the hydrostatic slide 93 is turned 90 degrees from the position shown in FIG. 13, the portion of the lower work rest 71 which has been below the work 17 becomes a space. By raising the pressure slide body 81, the work 17 can be easily attached and detached. According to this embodiment, via the disk 91 and the hydrostatic slide 93,
Since the lower work rest 71 follows the vertical movement of the lower grindstone table 20, the work 1 of the lower work rest 71 is
The height of the slide surface 77a for holding the workpiece 7 is at a position where the workpiece 17 being ground can always be held in a good horizontal position.
Moreover, a stable holding state can be obtained by absorbing thermal deformation and vibration.

(Sixth Embodiment) FIGS. 15 and 16 show the slide surface of a hydrostatic slide used in a sixth embodiment. In this embodiment, the work 17 is supported only by the lower work rest 71 without using the upper work rest 72.

As described above, the point that the portion 17b of the work 17 protruding from the grindstone is supported at two locations on one side by hydrostatic bearings is also the same in this embodiment.

In the figure, the lower static pressure slide 77 has a circular slide surface 77a as in the previous embodiment. A suction orifice 77 is provided at the center of the slide surface 77a.
The orifice 77c for discharge is disposed by arranging three circles around the orifice 77d for suction with d.

The gas discharged from the discharge orifice 77c enters between the discharge orifice 77c and the lower surface of the work 17 to form a static pressure fluid layer.

In this fluid static pressure layer, gas flows toward the suction orifice 77d that is being sucked. The negative pressure and the orifice diameter in the suction orifice 77d are provided so as to reduce the thickness of the fluid static pressure layer.

The work 17 floats at a position where the weight of the work 17 is balanced with the weight of the work 17, but the work 17 is caused to float at the periphery of the discharge-side orifice 77c from which gas is blown out, and the suction is performed. Since the work 17 is to be pulled in at the center of the orifice 77d, the work 17 and the slide surface 77a are balanced in a small gap state, so that the rigidity for supporting the work 17 can be improved.

According to this embodiment, the range in which the suction force of the suction orifice 77d is applied to the work 17 is small, so that the work 17 is not deformed and can be held rigidly.

In the embodiment of the present invention, a grinding wheel having a grinding wheel diameter of approximately one-half the diameter of the work is provided so that the grinding center passes through the rotation center of the work, and a grinding surface is provided on the outer peripheral side of the work. As a result, the inner diameter of the outer peripheral frame 57a of the rotating plate 57 that supports and rotates the work is small, and the rotating plate 57 is small, so that the work supporting member 14 is small.

In the embodiment of the present invention, when a portion of the work that has protruded from the outside of the grinding action surface of the grindstone is held by the work rest, the above-described work wheel having a diameter approximately half that of the work is used. The problem of how to maintain the position of a workpiece is solved.

In the embodiment of the present invention, as described above, a work support plate thinner than a wafer having a work set hole with a drive portion protruding into a notch provided for indicating the crystal orientation of the wafer is driven to rotate. Since the grindstones are simultaneously applied to the upper and lower surfaces of the wafer for grinding, there is an effect that the wafer is reliably fed in rotation, the grinding action acts on the entire surface of the wafer and both surfaces are simultaneously ground. And because of the grinding, good surface roughness can be secured in a short time, and when the wafer is sucked by the vacuum chuck, the wafer is pulled into the suction surface of the vacuum chuck, and is flattened. When processing is removed from the vacuum chuck, the shape is restored by the elasticity and the shape accuracy is deteriorated. However, according to this embodiment, since the work is not flattened to support the work, the shape accuracy is good.

Although the vertical double-sided surface grinding machine has been described as the grinding machine of the embodiment, a horizontal double-sided surface grinding machine may be used.

[0059]

According to the wafer processing method of the present invention, the position of the work portion protruding from the grindstone is regulated by the work rest. Therefore, even when the grindstone diameter is set to approximately one half of the work diameter, it is stable. Grinding is possible. And the support member of a work can be made small.

By forming the work rest as a hydrostatic slide using gas as the pressure fluid, the wafer is not damaged by the work rest and the work is damped, so that the grinding is performed stably. .

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of a double-ended surface grinder according to the present invention.

FIG. 2 is a longitudinal sectional view of a main part of a lower frame portion.

FIG. 3 is a longitudinal sectional view of a main part of an upper frame portion.

FIG. 4 is a plan view of a work supporting member.

FIG. 5 is a longitudinal sectional view showing a slide table unit.

FIG. 6 is a perspective view of the same.

FIG. 7 is a plan view showing a relationship between a grinding tool, a work, and a work rest.

FIG. 8 is a longitudinal sectional view of the grinding tool of FIG. 7;

FIG. 9 is a front view showing another example of the grinding tool.

FIG. 10 is a longitudinal sectional view of FIG. 9;

FIG. 11 is a plan view schematically showing a method of detecting a grinding wheel wear of a grinding wheel.

FIG. 12 is a longitudinal sectional view of a work supporting member.

FIG. 13 is a longitudinal sectional view showing a moving member of a work rest according to another embodiment.

FIG. 14 is a partially enlarged view of FIG. 2;

FIG. 15 is a sectional view taken along line AA of FIG. 16;

FIG. 16 is a plan view of a hydrostatic slide according to a seventh embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Grinding tool 2 ... Base plate 2a ... Concave fitting part 3 ... Diamond grindstone 3a ... Grinding working surface 6 ... Grindstone holder 6a ... Convex fitting part 7 ... Bolt 8 ... Diamond impregnating grindstone 11 ... Lower frame 12 ... Lower part Grinding wheel rotating / lifting mechanism 13 ... Upper grinding wheel rotating / lifting mechanism 14 ... Work support member 15 ... Lower grinding stone 15a ... Grinding working surface 16 ... Upper grinding stone 16a ... Grinding working surface 17 ... Work (wafer) 17a ... Notch 17b ... Part 20 ... Grinding stone Table 21 ... Guide 22 ... Lower wheel head moving motor 23 ... Ball screw 23a ... Ball nut 24 ... Lower shaft support 24a ... Guide part 24b ... Bracket 25 ... Lower wheel head lifting / lowering motor 26 ... Rotation transmission mechanism 27 ... Ball screw 28: Lower grinding wheel shaft 29: Grinding wheel holder 34: Grinding wheel drive motor 38: Upper shaft support 38a: Bracket 39: Guide 4 0 ... Moving motor 41 ... Ball screw 41a ... Ball nut 42 ... Upper grindstone shaft 43 ... Whetstone holder 48 ... Gritstone driving motor 52 ... Support table 53 ... Slide table 54 ... Guide rail 55 ... Slide table moving motor 56 ... Ball screw 56a: Ball nut 57: Rotating plate 57a: Outer frame 58: Guide roller 59: Gear 60: Work support plate 60a: Set hole 60b: Work drive unit 61: Rotating plate rotating motor 62: Gear 71: Lower work rest 72: Upper work rest 73 ... Rotary actuator 73a ... Output shaft 74 ... Arm 75 ... Base 75a ... Pressure fluid inlet 75b ... Fluid passage 76 ... Distance piece 77 ... Lower fluid static pressure slide 77a ... Slide surface 7
7b ... Fluid passage 77c ... Orifice 77d ... Suction orifice 78 ... Seal ring 79 ... Cylinder 79a ... Cylinder body 79b ... Cylinder bush 79c ... Pressure fluid inlet 79d ... Hole 79e, 79f ... Pressure fluid inlet / outlet 79g ... Cylinder lid 81 ... Upper hydrostatic slide main body 81a ... outer peripheral groove 8
1b Fluid passage 81c Orifice 81d Slide surface 81e Piston 84 Revolving shaft 85 Arm 86 Position sensor 91 Disc 92 Radial bearing 93 Hydrostatic slide 93a Lower slide 93
b: Upper slide 93c: Distance piece 111: Upper frame

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toyohashi Wada 100 Fukuno-cho, Higashi-Tonami-gun, Toyama Pref. Japan Co., Ltd. Niihira Toyama Toyama Plant (56) References JP-A-6-304854 (JP, A) JP-A Heihei 10-217079 (JP, A) JP-A-9-262747 (JP, A) JP-A-54-23608 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B24B 7/17 B24B 41/06 H01L 21/304 621

Claims (4)

(57) [Claims] 1. A method of processing a wafer after cutting from an ingot, comprising: a work supporting member that holds the wafer and rotates the wafer; and a pair of grindstones, the two grindstone end faces being opposed to each other to grind the wafer with the grindstone end faces. Prepare a double-sided surface grinder, and a work rest that holds the wafer immediatly and immovably by applying gas to only one side of the wafer so that the surface of the wafer that protrudes from the outer periphery of the grinding wheel at the contact portion between the wafer and the grinding wheel end surface The work supporting member rotates the wafer and the work rest holds the wafer from only one side, and grinds the wafer by applying the grindstone to both sides of the wafer so that the center of the wafer passes through the grinding wheel working surface. Wafer processing method. 2. A double-sided surface grinder in which a pair of grindstones are arranged with both grindstone end faces facing each other, and the disc surface of a disc-shaped work is machined by the grindstone end faces. A work supporting member to be rotated at a proper center, a grindstone, and when the grindstone is applied to the surface of the work, the surface of the work protruding from the grindstone acts on only one surface of the work to hold the work immediatly and inseparably. A double-sided surface grinder, comprising: a work rest; 3. The double-headed flat surface according to claim 2, wherein a gas suction orifice and a gas discharge orifice are provided in the work rest between the work rest and the work surface to form a hydrostatic slide. Grinder. 4. The double-sided surface grinding machine according to claim 3, wherein a plurality of discharge orifices are provided around the suction orifice.