JPH0740233A - Thickness measuring device of work - Google Patents

Abstract

PURPOSE:To carry out the measurement regardless of thickness of a surface plate by measuring thickness of a work in accordance with a difference between sensor measured values before and after machining by way of making one of two sensors contact with the upper surface of the work and the other contact with a lower surface plate in the state of sandwiching the work between the upper and lower surface plates. CONSTITUTION:In a device carrying out polishing by rotating a plural number of carriers 5 by a sun gear 3 and an internal gear 4 in a planetary gear shape and sandwiching a work 6 held by each of the carriers 5 by upper and lower surface plates 1, 2 from both sides, a work thickness measuring device 8 using two sensors 9 is provided free to revolve in a horizontal surface. At the time of thickness measurement of the work 6, machining is temporarily finished, and after revolving the work thickness measuring device 8 placed on a stand-by position to a measuring position, an air cylinder is extensively moved, a head end probe of each of the sensors 9 is inserted into two through holes of the upper surface plate 1, and one of the sensors 9 is made contact with the upper surface of the work 6 and the other is made contact the lower surface plate 2. From a difference of measured values of the sensors 9, thickness of the work 6 is detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat surface polishing apparatus for simultaneously polishing both surfaces of a work. More specifically, the present invention relates to a work thickness measuring device in a flat polishing device.

[0002]

2. Description of the Related Art Conventionally, as disclosed in Japanese Patent Publication No. 2-60467, at the center of a ring-shaped surface plate,
It is generally known that a magnetic sensor is used to measure the distance between the upper and lower surface plates, and this is replaced with the thickness of the work.

[0003]

However, in the present situation where the precision of the thickness dimension of the machined work is severely demanded, in the above-mentioned prior art, the upper and lower surface plates are worn and slight vibrations occur during the machining. Therefore, the thickness of the work could not be accurately measured. In order to solve this problem, before starting the first batch and after every few batches, the machine is stopped, the upper platen is lifted to take out the work, and the work is measured by a measuring device such as a dial gauge or a micrometer. It was necessary to measure the thickness, compare it with the work thickness displayed during processing, and input the correction value to the controller before starting the next batch processing. In view of this point, an object of the present invention is to provide a work thickness measuring device capable of measuring a value closer to the actual value.

[0004]

The present invention adopts the following technical means in order to solve the above problems. According to a first aspect of the present invention, in the surface polishing apparatus, driving of the upper and lower surface plates, the sun gear, and the internal gear is stopped, and one of the two sensors is placed in a state where the work is held between the upper and lower surface plates. A technical means was adopted in which the upper surface of the work and the other surface were brought into contact with the surface of the lower surface plate, and the thickness of the work was measured from the measurement difference by the sensor before and after processing. According to a second aspect of the present invention, in the surface polishing apparatus, the driving of the upper and lower surface plate, the sun gear, and the internal gear is stopped, and the work is held between the upper and lower surface plate,
A technical means is adopted in which one of the two sensors is brought into contact with the upper surface of the work and the other is brought into contact with the upper surface of the carrier, and the thickness of the work is measured from the difference between the sensors before and after processing.

[0005]

[Operation] With the upper and lower surface plates, the sun gear, and the internal gears stopped driving, one of the two sensors is placed on the upper surface of the work and the other is placed on the lower surface plate or the upper surface of the carrier while the workpiece is held between the upper and lower surface plates. Since the thickness of the work is measured from the values measured by the sensors that come into contact with each other before and after machining, it is possible to obtain a value that takes into account the wear of the upper and lower surface plates, and because machining is stopped, There is no effect of vibration. Furthermore, since the work is clamped between the upper and lower surface plates, the measurement can be restarted if the work thickness is larger than the final target value, which reduces the work time. Can be planned.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. First, FIGS. 1 to 3 show an embodiment of the present invention. This polishing apparatus is provided with upper and lower surface plates 1 and 2 coaxially positioned, a sun gear 3 and an internal gear 4 and both gears. The work 6 held by a plurality of carriers 5 driven in the form of planetary gears 3 and 4 is sandwiched between the upper and lower surface plates 1 and 2 from both sides and polished.

The machine body 7 is provided with a work thickness measuring device 8. The work thickness measuring device 8 has two sensors 9
(For example, a magnetic sensor) is moved up and down by an actuator such as an air cylinder 10 and a linear guide 11 and the like, and a measurement position a (solid line) and a standby position b (dotted line) in FIG. ) To rotate between. In this way, when measuring the thickness of the work, the processing is once finished with a target value by a sizing device or by time management. At this time, the sensor probe 14 of the sensor 9 is inserted into the two through holes 12 and 13 of the upper surface plate by stopping at a fixed position and rotating from the standby position to the measurement position. The thickness of the work 6 is measured by bringing it into contact with the lower surface plate surface or the carrier 5.

Next, in order to measure the work thickness using the work thickness measuring device 8, (1) In the case of a lapping machine, one sensor of the two sensors 9 is used as the upper surface of the work 6 and the other sensor. The lower surface plate 2
If they are brought into contact with the surface, the difference between the readings of the respective sensors becomes the work thickness. This will be described with reference to FIG. 4. The work thickness after processing is W = (reading of A) − (reading of B). Of course,
Before processing, both sensors may be brought into contact with the two surfaces of the lower surface plate to perform zero adjustment. (2) In the case of polishing machine, as shown in FIG.
Of the two sensors A and B, one sensor is brought into contact with the upper surface of the work 6 and the other sensor is brought into contact with the upper surface of the carrier 5, and the thickness of the carrier 5 is kept constant (a−c) + (the thickness of the carrier). Compare with the thickness of. Also in this case 2 before processing
All the sensors 9 of the book are brought into contact with the upper surface of the carrier 5 and
You may adjust it.

The work thickness measuring device thus constructed can be used alone as a thickness measuring device or can be used in combination with a conventional sizing device. In this case, the amount of lowering of the upper surface plate 1 is measured as the thickness of the work with the configuration as shown in FIG.
As disclosed in Japanese Patent Publication No. 7, the distance between the upper and lower stools is measured as the thickness of the work. In either case, the wear amount of the stool (the wear of the upper stool depends on the pressure and the polishing rate). However, since the wear of the lower surface plate affects the measurement of the thickness of the work), there is an error between the actual thickness and the target value. The work thickness measuring device of the present invention can be used to correct such an error. That is, the work thickness when the sizing device operates is thicker than the target value by the wear amount of the surface plate. Therefore, if you set a value that includes the ratio of the amount of work scraped and the amount of surface plate scraped to the target thickness, and the amount of surface plate wear that is expected at that time, and restart processing, the target Can be processed to thickness.

Further, instead of the conventional sizing device, it can be used together with polishing by time management. That is, the time required to reach the target value from the empirically obtained polishing rate is calculated, and after processing for that time, the actual thickness is measured with the work thickness measuring device of the present invention, and the remaining processing time is calculated. Can be set.

As described above, according to the present invention, the work thickness measuring device alone can be used to control the work thickness, and more accurate thickness control can be performed in combination with the conventional method. .

[0012]

As a result of adopting the above configuration, the present invention provides
The following effects can be obtained. (1) With a simple structure, measurement can be performed without being influenced by the wear of the surface plate. (2) If the work thickness measuring device is rotated to the standby position, the machining can be restarted as it is. (3) Better thickness control can be achieved by using it together with a conventional method, for example, a method of detecting the lower platen spacing as the thickness of the wafer.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a lapping apparatus for carrying out the present invention.

FIG. 2 is a cross-sectional view of essential parts showing the thickness measuring device of FIG.

FIG. 3 is a plan view of relevant parts showing measurement positions of the thickness measuring device of FIG.

FIG. 4 is an enlarged cross-sectional view of an essential part showing a state where one of the sensors of the present invention is in contact with the work and the other is in contact with the lower surface plate.

FIG. 5 is an enlarged cross-sectional view of an essential part showing a state where one of the sensors of the present invention is in contact with a work and the other is in contact with a carrier for measurement.

[Explanation of symbols]

1 ... upper surface plate 2 ... lower surface plate 3 ... sun gear 4 ... internal gear 5 ... carrier 6 ... work 7 ... machine body 8 ... thickness measuring device 9 ... sensor 10 ... air cylinder 11・ ・ ・ Straight guide 12, 13 ・ ・ ・ Through hole 14 ・ ・ ・ Sensor probe

Claims (2)

[Claims] 1. A flat-surface polishing apparatus for holding a work on a carrier that is meshed with a sun gear and an internal gear and driven like a planetary gear, and sandwiches the work from both sides by an upper platen and a lower platen for polishing. , The upper and lower surface plate, the sun gear, and the internal gear are stopped to be driven, and one of the two sensors is brought into contact with the upper surface of the work and the other surface of the lower surface plate with the workpiece held between the upper and lower surface plates, A work thickness measuring device that measures the work thickness from the measurement difference between the sensor before and after machining. 2. A flat polishing apparatus for holding a work on a carrier which is meshed with a sun gear and an internal gear and driven like a planetary gear, and sandwiches the work from both sides by an upper platen and a lower platen for polishing. , The upper and lower surface plate, the sun gear, and the internal gear are stopped to drive, with one of the two sensors in contact with the upper surface of the work and the upper surface of the carrier while the work is being held between the upper and lower surface plates. A work thickness measuring device that measures the work thickness from the difference between the front and rear sensors.