JPH0710494B2 - Wrapping device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a lapping apparatus, and more particularly to a lapping apparatus for polishing, for example, a silicon wafer by a lapping plate.

2. Description of the Related Art In a lapping machine using a lapping plate, it is necessary to measure the plane accuracy of the lapping plate and correct it in order to improve the processing accuracy.

In the conventional lapping machine, the flatness of the lap platen is measured using a straightness measuring bar in which a plurality of dial gauges are linearly arranged. However, the three-dimensional shape required for high precision lapping is unknown. Moreover, this measurement is performed only for the lower lapping platen, and for the double-sided lapping machine, the upper lapping platen is managed only in the radial direction, which is a plane shape far from the ideal plane.

In addition, the correction work of the lap surface plate can be done by the operator's intuition, depending on the shape such as the middle convex shape with the central part of the lap surface raised or the concave shape with the central part lowered. This is done by combining the rotation direction and rotation speed. Since the lap surface plate undergoes thermal deformation and elastic deformation due to lap processing heat and load, the corrected shape is determined know-how in consideration of wear during processing.Generally, the lower lap surface plate has a concave shape. Shape, the upper lap platen has a convex shape. Therefore, the correction work requires a considerable amount of time and experience and is a highly skilled work.

An object of the present invention is to solve the above problems and to provide a lapping apparatus capable of easily and surely measuring and correcting the plane accuracy of the upper and lower lapping platens and thus obtaining a highly accurate product.

Means for Solving the Problems A lapping apparatus according to the present invention includes a lower lap surface plate arranged upward, an upper lap surface plate arranged in a downward facing manner above the lower lap surface plate, and an upper surface of the lower lap surface plate. Has a plurality of distance sensors attached to a reversible measuring bar that can be rotated to a lower measurement position that measures the plane accuracy of the upper lapping plate and an upper measurement position that measures the plane accuracy of the lower surface of the upper lapping plate. In, the plane accuracy measuring means for measuring the plane accuracy of the surface of the lap surface by performing a process in which the output signal from the distance sensor, the positional relationship of the distance sensor, and the rotation angle position of the corresponding lap surface are associated with each other. And a reversible whetstone support member that can be rotated to a lower correction position that corrects the upper surface of the lower lap surface plate and an upper correction position that corrects the lower surface of the upper lap surface plate A correction means having a correction grindstone that is rotated, and at each correction position, the grindstone contacts the surface of the corresponding lapping plate and rotates, and the position of the grindstone with respect to the lapping plate, the contact pressure of the grinding stone, and the rotation speed can be adjusted. And control means for correcting the surface of the corresponding lapping plate by controlling the correction means at the corresponding correction position based on the measurement result of the plane accuracy measuring means at each measurement position.

Action Multiple distance sensors attached to a reversible measuring bar that can be rotated between a lower measurement position that measures the plane accuracy of the upper surface of the lower lap surface and an upper measurement position that measures the surface accuracy of the lower surface of the upper lap surface plate. Having the output signal from the distance sensor, the positional relationship of the distance sensor, and the corresponding rotation angle position of the lap surface plate at each measurement position, the flatness of the surface of the lap surface plate can be determined by performing the processing. Since it has a plane accuracy measuring means to measure, by reversing the measurement bar to the lower measurement position and the upper measurement position and changing the direction of the distance sensor, it is possible to use the upper lap surface plate as well as the lower lap surface plate. , Its three-dimensional shape can be easily and accurately measured.

Further, there is a correction grindstone attached to a reversible grindstone support member that is rotated to a lower correction position for correcting the upper surface of the lower lap surface plate and an upper correction position for correcting the lower surface of the upper lap surface plate. In the above, since the grindstone rotates in contact with the surface of the corresponding lap surface plate, the position of the grindstone with respect to the lap surface plate, the contact pressure of the grindstone, and the correction means capable of adjusting the rotation speed are provided. By reversing the correction position and the upper correction position and changing the direction of the grindstone, not only the lower lap surface plate but also the upper lap surface plate can easily and accurately correct any position on the surface by any amount. can do.

Further, since the control means for correcting the surface of the corresponding lapping plate is provided by controlling the correction means at the corresponding correction position based on the measurement result of the plane accuracy measurement means at each measurement position, the measurement of the plane accuracy is performed. Based on the result, it is possible to easily and accurately correct the upper and lower lap surface plates into an arbitrary shape.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic configuration of a portion related to plane accuracy measurement and correction of a double-sided lapping machine.

The lapping device includes upper and lower lapping plates (10) (11), a plane accuracy measuring device (12), a correction device (13), and a control device (14).

The lower lap surface plate (lower surface plate) (11) is arranged facing upward.

The upper lapping plate (upper plate) (10) is the lower lapping plate (11)
It is arranged above and above in a downward facing manner so that it can be moved up and down to adjust the distance to the lower surface plate (11).

The control device (14) is, for example, a personal computer, to which a graphic display (15) or the like is connected.

The plane accuracy measuring device (12) is configured as follows (see FIGS. 2 and 3).

The plane accuracy measuring device (12) includes one measuring bar (16). Both ends of the measuring bar (16) are
It is supported by 7) and the block (17) is the support base (18).
It is mounted so that the height can be adjusted. The support base (18) is installed on a device outside the lower surface plate (11) so that the measurement bar (16) is located between the upper and lower surface plates (10) and (11). A plurality of (for example, about 10) distance sensors (19) are linearly arranged on the measurement bar (16). Further, an optical switch (20) for height adjustment is provided at a portion near both ends of the measurement bar (16). The measurement bar (16) is rotated 180 degrees with respect to the block (17), so that the distance sensor (19) faces the upper surface of the lower platen (11) and the lower measurement position and the distance sensor (19) are the upper platen. (10) Switch to the upper measurement position that faces the lower surface.
And at the upper or lower measurement position,
By adjusting the height of the block (17) using the optical switch (20), all the distance sensors (19) are on the surface plate (1
0) The height of the measuring bar (16) is adjusted so that it lies in one plane substantially parallel to the surface of (11), preferably in a horizontal plane.

A marker (21) is attached to the peripheral portion of the upper surface of the upper surface plate (10), and a marker sensor for determining the rotation angle of the upper surface plate (10) by detecting the marker (21) at the fixed part of the device. (22) is provided. Similarly, a marker (23) is attached to the lower surface peripheral portion of the lower surface plate (11), and the rotation angle of the lower surface plate (11) is obtained by detecting this marker (23) on the fixed part of the device. Marker sensor (24) is provided.

Distance sensor (19) of measuring bar (16), optical switch for height adjustment (20) and marker sensor (22) (24)
Is connected to the control device (14). Control equipment (14)
Performs the processing in which the outputs of the plurality of distance sensors (19) of the measurement bar (16), the positional relationship between these distance sensors (19), and the rotation angles of the surface plates (10) (11) are associated with each other. By doing so, the plane accuracy of the surface plate (10) (11) is measured.

Next, referring to FIG. 3, the above-mentioned plane accuracy measuring device (1
The principle of plane accuracy measurement of the lower surface plate (11) by 2) is explained.

FIG. 3 shows the measurement line at each rotation position of 40 ° when the measurement bar (16) is installed on the lapping machine and the lower surface plate (11) is rotated. 10 on the measuring bar (16)
About 6 distance sensors (19) are attached, but in the figure, the positions of the 6 distance sensors (19) that are necessary in principle, j =,
,,,, are shown. Also, the lower surface plate (1
The position of the measuring bar (16) by the rotation of 1) is i = 1 , 2 ,
..., represented by 9 .

The output d _{i, j} of the distance sensor (19) of the measuring bar (16) is expressed as d _{i, j} = a _i · x _j + b _i + f _{i, j} (1). However, i is the rotational position of the lower surface plate (11) of 1 , ..., 9 and j is the sensor position of. Further, a and b are parameters of the straight line on the upper surface of the cut surface when the surface moving along with the rotation of the lower surface plate is cut by the measuring bar, and f is a deviation amount from the straight line, that is, a plane strain amount.

The basic idea of the measuring method by this plane accuracy measuring device (12) is based on the measured values at three points A, B and C in FIG. 3, and assuming that these points are in the horizontal plane, the point A , B, and C _, to obtain f _{i, j} from measured values d _{i, j} . The specific procedure will be described below.

First, f _{i, j} on positions 1 , 4 , and 7 passing points A, B, and C are obtained.

The measurement data at point A is1of,FourGiven as
From the formula (1), d_i,= A ₁ ・ X + B ₁ + F _{1 ,} ……… (2) d _{4 ,}= A _Four ・ X + B _Four + F _{4 ,} ……… (3)1 NotoFourAre in the same position (point A), so f _{4 ,}= F _{4 ,} Is.

Since this position is used as a reference, f _{4 ,}= 0
Good. On the other hand, x = 0 at the center of the measuring bar (16)
Then, from the symmetry of the position of the sensor (19), x
= -X Becomes

Since the same applies to the positions of the points B and C, d _{7 ,}= A ₇ ・ X + B ₇ + F _{7 ,} ……… (4) d _{1 ,}= A ₁ ・ X + B ₁ + F _{1 ,} ……… (5) d _{4 ,}= A _Four ・ X + B _Four + F _{4 ,} ……… (6) d _{7 ,}= A ₇ ・ X + B ₇ + F _{7 ,} ……… (7) and f _{7 ,}= F _{1 ,}= 0 f _{4 ,}= F _{7 ,}= 0.

From equations (2) and (5), a ₁ = (D _{1 ,}-D _{1 ,}) / (2x ) ………
(8) b ₁ = (D _{1 ,}-D _{1 ,}) / 2 ……… (9) From equations (3) and (6), a _Four = (D _{4 ,}-D _{4 ,}) / (2x ) ………
(10) b _Four = (D _{4 ,}-D _{4 ,}) / 2 ……… (11) From equations (4) and (7), a ₇ = (D _{7 ,}-D _{7 ,}) / (2x ) ………
(12) b ₇ = (D _{7 ,}-D _{7 ,}) / 2 ……… (13) Therefore,1The plane strain f above is the value of the equations (8) and (9).
Using f _{1 , j}= D _{1 , j}-A ₁ ・ X_j-B ₁  … It can be obtained by (14).

Similarly, the plane strain f on 4 is obtained from the equations (10) and (11), and the plane strain f on 7 is obtained from the equations (12) and (13).

Next, f _{i, j} at positions other than 1 , 4 , and 7 are obtained. 1, 4, 7 at a position other than the values of a, b are determined from the relationship between 1, 4, 7.

For example, in FIG. 3, a and b at position 2 are obtained as follows. Since 2 and 4 and 1 and 2 are the same point, f _{2 ,} = f _{4 ,} ... (15) f _{2 ,} = f _{1 ,} ... (16) where f _{4 ,} And f ₁ have already been obtained at positions 4 and 1 as described above.

Therefore, d _{2 ,}= A _Two ・ X + B _Two + F _{2 ,} ……… (17) d _{2 ,}= A _Two ・ X + B _Two + F _{2 ,} ……… (18), so a _Two = [(D _{2 ,}-D _{2 ,})-(F _{2 ,}-F
_{2 ,})] / (X -X ) ………… (19) b _Two = D _{2 ,}-F _{2 ,}-A _Two ・ X  ……… (20). Therefore,TwoAll the above f are required
Will be.

For the other positions 3 , 5 , 6 , 8 , 8 and 9 , similarly, f
Can be obtained.

Although d _{i, j} is a measured value, it is desirable to use a smoothed value for each position i when processing by the above procedure.

Also, it is desirable to input the data at each position i at the same time, but in reality, the sensor is scanned, and the lower surface plate (1
Since 1) rotates, it will measure the position deviating from the original position. Now, when a work with a diameter of 1 m is rotating at 10 rpm, the outermost circumference is about 500 mm / sec. Therefore, if it can be input within 10 msec, the maximum amount of measurement position deviation will be 5 mm, so it is considered that there is no practical problem.

The plane accuracy of the upper surface plate (10) is similarly measured with the measurement bar (16) switched to the upper measurement position.

The correction device (13) is configured as follows (see FIG. 4).

An elevating table (27) is fixed to the upper end of the column (26) that moves up and down with respect to the base (25). A swivel base (28) is attached to the lift base (27), and is swung about a vertical axis by a swiveling motor (29) mounted on the lift base (27).
A base end portion of the arm (30) is attached to the upper part of the swivel base (28) so as to be vertically rotatable by a horizontal pin (31).
A grindstone support member (32) is attached to the tip of the arm (30). A grindstone drive motor (33) is attached to the tip of this member (32), and a correction grindstone (37) is attached to the tip of the motor shaft (34) through a spherical joint (35) and a spring (36).
Is installed. Two levers (38) and (39) are rotatably attached to the swivel base (28) by pins (40) and (41) parallel to the pins (31) of the arm (30), and each lever (38). The pressure adjustment motors (42) (4
The pressure adjustment screws (44) (45) that can be raised and lowered by 3) are pressed. A first tension spring (46) is attached between a portion of the first lever (38) opposite to the screw (44) and a portion of the arm (30) closer to the tip end than the pin (31), and a second tension spring (46) is attached.
A second tension spring (47) is mounted between a portion of the lever (39) opposite to the screw (46) and a portion of the arm (30) closer to the base end than the pin (31).

By reversing the grindstone support member (32) with respect to the arm (30) by 180 degrees, the grindstone (37) moves to the lower correction position facing the upper surface of the lower surface plate (11) and the lower surface of the upper surface plate (10). To the upper correction position opposite to. In the lower correction position, the grindstone (37) is pressed against the upper surface of the lower surface plate (11) by the elastic force of the first spring (46), and the spherical joint (35) and the spring (36) work to bring it into close contact. To be Then, the upper surface of the lower surface plate (11) is polished by rotating the grindstone (37) with the drive motor (33), and the first pressure adjusting screw (44) is rotated with the first pressure adjusting motor (42). By adjusting the position, the pressure contact force of the grindstone (37), that is, the polishing amount is adjusted. In the upper correction position, the grindstone (37) is moved by the elastic force of the second spring (47) into the upper surface plate (1).
It is pressed against the lower surface of (0) and is also closely attached to it. Then, by adjusting the position of the second pressure adjusting screw (45) by the second pressure adjusting motor (43), the pressure contact force of the grindstone (37) to the upper surface plate (10), that is, the polishing amount is adjusted. It In addition, when reversing the grindstone (37),
The upper surface plate (10) is moved upward, and the lifting table (27) and the swivel table (28) are moved upward so that this does not interfere with the upper and lower surface plates (10) (11).

The motors (29) (33) (42) (43) are connected to the control device (14). The control device (14) has a turning motor (2
By controlling 9), the swivel base (28) and the arm (30) are swung to change the radial position of the grindstone (37) with respect to the surface plate (10) (11), and the marker sensor (22). The position of the grindstone (37) with respect to the surface plate (10) (11) is obtained from the rotation angle of the surface plate (10) (11) detected by the (24) and the position in the radial direction. In addition, the drive motor (3
3) is controlled to adjust the rotational speed of the grindstone (37), that is, the polishing amount, and the pressure adjusting motors (42) (43) are controlled to adjust the pressure contact force of the grindstone (37).

The work of correcting the surface plates (10) (11) is performed as follows, for example.

First, the measuring bar (16) of the measuring device (12) is switched to the lower measuring position, the grindstone (37) of the correcting device (13) is switched to the lower correcting position, and the lower surface plate (11) is rotated at a low speed. The control device (14) controls the correction device (13) on the basis of the planar shape of the lower surface plate (11) obtained by processing the output signal from the measuring device (12) as described above. By doing so, the lower surface plate (11) is corrected. That is, if the error of the plane shape measured by the plane accuracy measuring device (12) is larger than the control value, this is fed back and a correction command is issued to the correction device (13) to polish the high part of the surface plate (11). And bring this closer to the ideal side. At this time, the pressure contact force of the grindstone (37) is high in the high part of the lower surface plate (11), and the grindstone (37) is in the low part of the lower surface plate (11).
The lower surface plate (11) is corrected to an ideal surface by lowering the pressure contact force of. Grinding stones (37)
The number of rotations may be changed, or both of them may be used in combination. Then, the above operation is performed until the planar shape measured by the measuring device (12) becomes ideal.

It should be noted that the above correction work may be performed by once operating the correction device (13) after measuring the planar shape with the measurement device (12) and repeating this until an ideal surface is obtained. Good.

When the correction of the lower surface plate (11) is completed, the measuring bar (16) of the plane accuracy measuring device (12) is switched to the upper measuring position, and the grindstone (37) of the correcting device (13) is moved to the upper correcting position. Switch and similarly correct the upper surface plate (10).

FIG. 5 shows a conventional lapping plate.

In the figure, the surface (lap surface) of the lapping plate (50)
A plurality of grooves (51) orthogonal to each other are formed on the base plate, and the lap platen is separated from the base plate portion (53) on the back surface (52) side of the bottom of the groove (51) by the groove (51). It is divided into a plurality of lap cell parts (54). To give an example of the dimensions, the overall thickness H of the lapping plate is 45 mm,
The height of the lap cell portion (54), that is, the depth (groove depth) d of the groove (51) is 15 to 17 mm, and the width (lap cell portion width) B of the lap cell portion (54) is 40 mm at the maximum (see FIG. 6). ).

In such a lapping plate, since the ratio (d / B) of the groove depth d and the lapping cell width B is small, as shown in FIG.
The amount of heat q generated by lapping flows linearly from the lapping surface (50) to the base plate portion (53) side, and a large temperature gradient is generated in the thickness direction inside the base plate portion (53). Undergoes thermal deformation into a spherical shape with a convex shape protruding toward the lap surface (50). The radius R of this thermal deformation is expressed by the following equation (21), assuming that the periphery of the lapping platen is in a free state.

R = t / α · θ (21) In the above equation, t is the thickness of the base plate (base plate thickness), α is the linear expansion coefficient of the lapping plate,
θ represents a temperature difference between the front side and the back side of the base plate portion (53).

As is clear from the equation (21), it is necessary to reduce α and θ in order to keep t constant and reduce thermal deformation (R is large).

However, in the case of the above-mentioned lapping plate, since the temperature difference θ of the base plate portion (53) is large, thermal deformation is large. Therefore, at present, at the beginning of work, idle operation is performed until a thermal steady state is reached.

Therefore, for example, as shown in FIG. 7, it is desirable to use a lapping plate having means for making the temperature distribution in the thickness direction of the base plate portion substantially uniform in the lapping cell portion.

In FIG. 7, the groove depth d of the lapping plate is, for example, about 3 times as deep as that of the conventional one.

Since the ratio (d / B) of the groove depth d and the width B of the lap cell portion is large, the heat quantity q mainly flows toward the side surface (55) of the lap cell portion (54) as shown in FIG. Therefore, heat is prevented from flowing into the base plate portion (53), the temperature distribution in the thickness direction of the base plate portion (53) becomes substantially uniform, and thermal deformation does not occur in the base plate portion (53).
Further, the lap cell part (54) has an axially symmetric temperature distribution, which causes a temperature difference, but the lap cell part (54) has a groove (5
Since they are separated by 1) and the width B of the lap cell portion is smaller than the diameter of the lap platen, the deformation of the lap cell portion (54) can be ignored. Therefore, the thermal deformation of the lap surface (50) is very small.

In the lapping machine, the upper lap surface plate is usually fixed to the lower surface of the surface plate attachment plate by bolts.

Generally, in a wrapping machine, as described above,
Due to the generation of processing heat, the temperature of the lapping plate rises and thermal expansion occurs. However, since the lap surface plate is fixed to the surface plate attachment plate by bolts, this thermal expansion cannot be absorbed, and the lap surface plate is thermally deformed into a convex shape with the central side protruding.

For this reason, it is desirable to adopt the upper surface plate mounting method as shown in FIG.

Fig. 9 shows the surface plate mounting plate (60) for the lapping machine.
And the part of the upper lap surface plate (10) attached to this.

On the upper surface of the lap surface plate (10), screw holes (62) are formed at a plurality of points equally dividing the circumference around the center, and the first screws (63) are screwed into the screw holes (62). . A bracket with a hole (63a) is integrally formed on the upper end of the screw (63). In addition, torque pin holes (64) are formed at a plurality of positions on the inner diameter side of the upper surface of the lap surface plate (10) that equally divides the circumference around the center thereof.

A plurality of through holes (65) corresponding to the screw holes (62) of the lapping plate (10) are formed in the mounting plate (60). The lower part of the second screw (66) is inserted into the upper part of the through hole (65). A bracket with a hole (66a) is integrally formed at the lower end of the second screw (66). An adjusting nut (67) and a lock nut (68) are fitted on the second screw (66), and the lower surface of the adjusting nut (67) is in contact with the upper surface of the peripheral portion of the through hole (65). A tension coil spring (69) is inserted into the through hole (65), the lower end of which is in the hole of the bracket (63a) of the first screw (63) and the upper end of which is the bracket (66a) of the second screw (66). It is fixed in each hole. Then, this spring (69) causes the lapping plate (1
0) is pulled upward and pressed against the lower surface of the mounting plate (60). A wrench hook (66b) is formed on the upper part of the second screw (66), and the lock nut (68)
By loosening and rotating the second screw (66), the pressure contact force of the lap surface plate (11) by the spring (69) can be adjusted.

A plurality of torque pins (70) fitted in the pin holes (64) of the lapping plate (11) are fixed to the mounting plate (60). There is some play between the torque pin (70) and the pin hole (64) so that the lapping plate (11) can move in the radial direction with respect to the mounting plate (60).

In this case, the rotation of the mounting plate (60) is transmitted to the lapping plate (1) via the torque pin (70), and the lapping plate (1)
0) rotates.

When the temperature of the lapping platen (10) rises due to the processing heat, thermal expansion occurs in the lapping platen (10). However, the lap surface plate (10) has the mounting plate (60) at both the connecting portion by the spring (69) and the torque pin (70).
Since it can move in a radial direction, the thermal expansion is absorbed in this portion, and the thermal deformation of the convex shape is very small.

FIG. 10 shows a schematic configuration of a portion related to processing of the above-mentioned double-sided lapping machine.

The double-sided lapping machine includes a sun gear (72), an internal gear (73) and a planetary gear (74) in addition to the upper and lower surface plates (10, 11).

The sun gear (72) is concentrically arranged in the center between the upper and lower surface plates (10, 11).

The internal gear (73) is arranged concentrically around the upper and lower platens (10, 11).

The planetary gear (74) is arranged between the sun gear (72) and the internal gear (73) between the upper and lower surface plates (10) (11) and meshes with them. A work storage pocket (hole) (75) is formed in the planetary gear (74), and a work (76) is put in this pocket (75), and both upper and lower sides of the workout pocket come out from the planetary gear (74). There is.

Surface plate (10) (11), sun gear (72) and internal gear (7
3) are rotated independently of one another or in relation to one another by suitable drive means.

In a normal lapping machine, upper and lower surface plates (10) (11)
The rotation direction of the planetary gears is always the opposite direction, and even if the ideal relative rotation condition is satisfied on the lower platen (11) side, the planetary gear (74) rotates on the upper platen (10) side. The relative machining speed differs by the speed, and the machining state deviates from the ideal condition. Therefore, it is impossible to perform ideal flat surface processing on both upper and lower surfaces.

Therefore, the above method may be used during roughing (heavy load) in the initial stage of lapping, but it is desirable to employ the following processing method during medium / finishing (light load).

That is, first, the upper and lower surface plates (10, 11) are rotated in the same direction at the same speed. In addition, the direction (hereinafter simply referred to as relative rotation direction) and speed (hereinafter simply referred to as relative rotation speed) of the relative rotation of the surface plate (10) (11) with respect to the revolution of the planetary gear (74) are determined by the rotation of the planetary gear (74). Equal to direction and speed.

By doing so, the upper and lower surface plates (10, 11) rotate in the same direction and at the same speed, so that the upper and lower surfaces of the workpiece (76) are processed in the same state. Moreover, since the relative rotation direction and the relative rotation speed of the surface plate (10) (11) are equal to the rotation direction and the rotation speed of the planetary gear (74), as described below,
In each part of the work (76) that rotates integrally with the planetary gear (74), the average values of the relative speeds with the surface plates (10) and (11) become substantially equal, and ideal flat surface machining is performed.

In FIG. 11, the relative rotation direction of the surface plates (10) and (11) is counterclockwise, and the relative rotation speed is N (rpm).
The rotation direction in 4) is counterclockwise and the rotation speed is n (rpm). In addition, the points on the work (76) that are on the straight line passing through the center O _S of the sun gear (72) and the center O _C of the planetary gear (74) and are separated by r from O _C to the outside are from A and O _C. r apart points on the workpiece (76) and B inwardly, the distance from O _S to O _C r _C,
The distance from O _S to A r _A, the distance from O _S to B and r _B.

The lapping amount W is expressed by the following equation (22).

W∝p ・ v / t ……… (22) where p (kgf / cm ² ) is the lapping pressure, and v (cm / min) is the lapping speed (workpiece (76) and surface plate (10) (11)). Relative speed), t (min) is a lap time.

From the formula (22), in order to machine the work into an ideal plane, the product of p and v should be constant in the machining plane, and in the ideal plane lapping plate, p is constant, so v is an average value ( The average lap speed) v _M should be kept constant.

O _C assuming that the planetary gear (74) is not rotating,
Assuming that the lap speeds in A and B (temporary lap speeds) are v _CR , v _AR and v _BR , respectively, these are given by the following equation (2
It is represented by 3) to (25).

v _CR = 2πr _C · N (23) v _AR = 2πr _A · N (24) v _BR = 2πr _B · N (25) Also, the planet gear (74) is at speed n. If you are spinning
Lap speed at O _C , A and B (true lap speed)
Are respectively v _C , v _A and v _B , these are expressed by the following equations (26) to (28).

At o _C , the speed due to rotation is 0, so v _C = V _CR = 2πr _C · N (26) At A, the decrease in speed due to rotation is 2πr · n, so v _A = V _AR −2πr · n = 2πr _A · N−2πr · n (27) At B, since the increase in speed due to rotation is 2πr · n, v _B = v _BR + 2πr · n = 2πr _B · N + 2πr · n (28) From equations (27) and (28), n and N when v _A = v _B.
If the relationship of is obtained, the following equation (29) is obtained.

_{n = (r A -r B)} N / 2r ......... (29) where, since a r _A -r _B = 2r, becomes n = N ......... (30).

Substituting equation (30) into equation (27) yields v _A = 2π (r _A −r) · N (31), and r _A −r = r _C , so v _A = 2πr _C · N = v _C (32)

Further, by substituting equation (30) into equation _{(28), v B = 2π} (r B + r) · N ......... (33) where, since a _{r B + r = r C,} v B = 2πr C・ N ＝ v _C ………… (34) Therefore, if n = N, v _A ＝ v _B ＝ v _C , and the average lap speed v _M is almost constant at all points on the work (76). .

Planar accuracy measuring device (12) used in the above embodiments
Is similar to that of Japanese Patent Application No. 62-36371 previously proposed by the present inventors, but the configuration of the plane accuracy measuring device (12) is not limited to this.

The present invention can also be applied to a single-sided lapping device.

EFFECTS OF THE INVENTION According to the lapping apparatus of the present invention, as described above, it is possible to easily and surely measure and correct the plane accuracy of the upper and lower lapping plates, and obtain a highly accurate product.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a portion relating to plane accuracy measurement and correction of a double-sided lapping machine showing an embodiment of the present invention, and FIG. 2 is a partially cutaway side view showing a portion of the plane accuracy measuring apparatus of FIG. , FIG. 3 is a drawing for explaining the principle of plane accuracy measurement, FIG. 4 is a partially cutaway side view showing a portion of the correction device of FIG. 1, and FIG. 5 is a main part of a normal lapping platen. FIG. 6 is a partially cutaway perspective view showing the heat transfer and temperature distribution of the lap platen of FIG. 5, and FIG. 7 is a part of the main part of the lap platen with small thermal deformation. FIG. 8 is a cutaway perspective view, FIG. 8 is an explanatory view showing heat transfer and temperature distribution of the lap surface plate of FIG. 7, and FIG. 9 is a vertical cross-sectional view showing a mounting structure of an upper lap surface plate with small thermal deformation. Fig. 10 is a schematic perspective view of the part related to the processing of the double-sided lapping machine, and Fig. 11 is an explanatory view explaining the principle of the processing. is there. (10) …… Upper lapping plate, (11) …… Lower lapping plate, (12) …… Plane accuracy measuring device, (13) …… Correction device, (14) …… Control device, (16)… … Measuring bar, (19)
…… Distance sensor, (32) …… Grinding stone support member, (37)…
… A modified whetstone.

Claims (1)

[Claims] 1. A lower lap surface plate which is arranged upward, an upper lap surface plate which is arranged above the lower lap surface plate so as to face downward, and a lower measurement position for measuring the plane accuracy of the upper surface of the lower lap surface plate. And a plurality of distance sensors attached to a reversible measurement bar that can be rotated to an upper measurement position that measures the plane accuracy of the lower surface of the upper lap surface plate, and an output signal from the distance sensor at each measurement position. , The plane accuracy measuring means for measuring the plane accuracy of the surface of the lap surface plate by performing the processing in which the positional relationship of the distance sensor and the rotation angle position of the corresponding lap surface plate are associated, and the upper surface of the lower lap surface plate is corrected. A reversible grindstone supporting member that is rotated between a lower retouching position for rotating and an upper retouching position for revising the lower surface of the upper lapping plate. Is rotated by contacting the surface of the corresponding lapping plate and adjusting the position of the grinding stone with respect to the lapping plate, the contact pressure of the grinding stone and the rotation speed, and the measurement results of the plane accuracy measuring means at each measuring position. And a control means for correcting the surface of the corresponding lapping plate by controlling the correction means at the corresponding correction position based on the lapping apparatus.