SU1093492A1 - Planar grinding machine - Google Patents

Abstract

1. PLATE GRINDING MACHINE, containing a frame, a rotary table for fastening parts, spindles for roughing, semi-finishing and finishing, a device for actively controlling the thickness of the parts being machined, which differ from 1K; so that, in order to increase the machining accuracy, the machine is equipped with a holder on the table for attaching the control sample, and the spindles are installed at different distances from the axis of rotation of the table with an increase in radius, starting from the finishing spindle, while the sensors of the active control device are located above the holder for mounting the control sample. 2. The machine according to claim 1, characterized in that the holder for fastening the test specimen is mounted with the possibility of vertical movement.

Description

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Fig, 1

The invention relates to abrasive machining and can be used in the grinding of flat surfaces of parts, in particular semiconductor wafers or photomask glasses.

A surface grinding machine is known, which contains three vertically arranged spindle heads with cup-type diamond wheels that can be vertically moved by an actuator controlled from plate thickness measuring devices, a rotary table with suction cups to hold the plate, three devices for measuring the plate thickness after grinding each spindle, a plate washing device, a device for loading and unloading plates from a turntable 1.

The disadvantages of the known machine are the lack of accuracy of processing due to the low accuracy of the measurement of the thickness of the processed plates, as well as the difficulty in maintaining it.

The accuracy of measuring the thickness of the plates is low due to the fact that the sensors for measuring the thickness are located directly near the shafts, i.e. in the grinding zone of the plates, as a result of which the measurement is performed on the contaminated surface of the plates covered with a silicon-silicon mixture.

The complexity of servicing the machine is due to the fact that to adjust it, a tuning plate (a suitable plate) is needed, which is sequentially inserted under each of the three spindles, starting with a coarse grinding spindle and ending with a finishing spindle. This operation leads to the deterioration of one or several suitable plates, and also requires a large investment of time, since each successive sequence is possible to adjust only during the setting of the previous one.

The aim of the invention is to improve the accuracy of processing.

The goal is achieved by the fact that a surface grinding machine containing a bed, a rotary table for fastening parts, roughing, finishing and finishing spindles, a device for actively controlling the thickness of the parts being machined is provided with a holder held on the table for fixing the test specimen, and the spindles are mounted from the axis of rotation of the table with an increase in the radius, starting from the shpinddel of finishing, while the sensors of the active control device are located above the holder m for fastening control sample.

A holder for reducing the test specimen is mounted with the possibility of vertical movement and provided with a drive of vertical movement.

FIG. 1 is a schematically depicted flat-face. machine cut; in fig. 2 - the same, top view.

The surface grinding machine contains a table 1 with vacuum suction cups - 2 machined plates 3, a finishing spindle 4, a semi-finishing spindle 5, a rough machining spindle 6 with diamond wheels 7-9 a control sample holder 10, a control sample 11, sensors 12-14 devices active control of the thickness of the processed plates: drive holder

control sample, incl. pneumatic cylinder 15, screw 16 and nut 17 with friction outer surface. The distance from the center of the table 1 to the axis of the spindle 5 is larger than from the center of the table to the axis of the pin 4, and the distance from the center of the table 1 to

The 5 axis of the spindle 6 is larger than the distance from the center of the table to the axis of the spindle 5. The difference in the distances of the spindles from the center of the table is chosen because of the condition that each spindle interacts with the control sample 11, i.e.

 diamond circles of 7–9 spindles 4 – b left the corresponding traces of processing, II, III on the control m sample 11 (Fig. 2).

5 Surface grinding machine works as follows.

Before starting work by grinding the control sample 11 and measuring the height of steps I, II, III. On the control sample (Fig. 2), the spindles 4-6 are adjusted to remove the specified allowances. Immediately before grinding the plates, the control sample 11 with the help of the screw 16 and the nut 17, which is rotated by the pneumatic cylinder 15, rises to a height of 0.05-0.1 mm from the level at which

finished setting the spindles of the machine. The plates 3 to be processed are fixed on the table 1 by vacuum. As the table 1 rotates, the plates 3 successively pass under rotating circles of 7-9 spindles 4-6 of diamond.

0 At the same time, the control sample 11 is also simultaneously grinded. After the control sample passes under all the spindles and also passes the wash zone (not shown), it passes under the sensors 12-14 of the active control devices. According to the results of measuring the height of the steps I, 11, III of the control sample 11, the sensors 12-14 give the command to adjust the height of the diamond tools 7–9 shafts 4-b above the vacuum level.

Q holders 2.

Before the start of each subsequent revolution of the table 1, the pilot sample 11 with a screw 16 and a nut 17, rotated by a pneumatic cylinder 15, rises 0.05-0.1 mm upwards.

5 Thus, in the proposed construction of the machine, the height of the steps I, II, - ill above the level of the vacuum X holders 2 is equal to the thickness of the processed plates after

remove corresponding allowances from them. In this case, the magnitude of the removed allowances is measured not by measuring the thickness of the plates being processed directly in the treatment area, as is the case in a known machine, but by measuring the corresponding steps of the control sample that has passed the washing zone. Due to this, the accuracy of measurement is increased, and consequently, the accuracy of processing, since

before measuring, the water-silicon mixture and abrasive tools wear products are completely removed from the surface of the control sample: In addition, the setup of the machine is greatly simplified and the need for using adjustment plates is eliminated, which leads to an increase in serviceability of the machine as a whole. At the expense of an increase in the processing accuracy, the yield of suitable plates increases on average by 5%.

FIG 2

Claims (2)

1. A PLANE GRINDING MACHINE containing a bed, a rotary table for attaching parts, spindles for roughing, finishing and finishing, an active control device for the thickness of the workpieces, characterized in that, in order to increase the accuracy of processing, the machine is equipped with a holder on the table for attaching a control sample, and the spindles are installed at different distances from the axis of rotation of the table with increasing radius, starting from the finishing spindle, while the sensors of the active control device are above the holder for attaching a control sample. 2. Machine on π. 1, characterized in that the holder for attaching the control sample is installed with the possibility of vertical movement. Figure 1