JPH0695506B2 - Double-sided lapping machine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement of a double-sided lapping machine for wrapping a wafer such as a work piece such as a metal or a semiconductor, and more specifically, swinging the wafer on a work surface. The present invention relates to a double-sided lapping machine that corrects each processing surface of the upper and lower surface plates while wrapping.

[Prior Art] Conventionally, in order to wrap a workpiece such as a semiconductor wafer, a method in which a wafer is attached to a plate and the attachment side is faced down and pressed against a processed surface of a rotary platen is generally used. .
However, since this method is inefficient, as a device for facilitating automation, it is carried out by eccentricity so as to partially overlap in the horizontal direction and holding a wafer held by one carrier between lower stools. A lap machine was developed.

[Problems to be Solved by the Invention] However, in such a lapping machine, 1) the wafer can be lapped only on each side.

2) Since the carrier that holds the wafer is free rotating, lapping tends to be uneven.

3) Only the machined surface of the lower surface plate can be corrected, so it is difficult to secure the surface accuracy of the wafer.

There was a problem in that.

As an apparatus for solving such a problem, a polishing apparatus for a semiconductor wafer, which simultaneously polishes both surfaces, has been proposed (JP-A-58-58).
122733 publication). This device is not a lapping of a semiconductor wafer, but a polishing device for mirror-polishing both surfaces of a wafer. The wafer is forcibly driven by a sun gear and an internal gear to simultaneously polish both surfaces of a workpiece. Therefore, the problems of 1) and 2) above are cleared. However, the polishing platen of the polishing apparatus is not required to be modified so much, and it must be repaired separately from the polishing of the wafer. Further, the apparatus includes a large number of water ejection holes for forming a water film in the apparatus, a wafer gripping mechanism that moves above the polishing carrier surface, a wafer detection sensor mechanism, a wafer transfer mechanism, and a sequence control unit for driving each mechanism. It has a complicated structure and function provided with members, is an expensive polishing device that is difficult to automate, and is a polishing device that is industrially disadvantageous.

Therefore, an object of the present invention is to provide an apparatus having a relatively simple structure and capable of lapping both surfaces of a work piece simultaneously and with high accuracy. Another issue is
It is an object of the present invention to provide a more industrially advantageous double-sided lapping machine in which the working surfaces of the upper and lower surface plates are effectively corrected during the lapping operation, and continuous lapping is possible.

[Means for Solving the Problems] Therefore, the present inventor has conducted various studies and, as a result, simultaneously laps both surfaces of the wafer to enhance work efficiency, forcibly rotates the carrier to uniformly lap the wafer, and further wraps the wafer. While performing the above, a lap machine for correcting the processed surface of the upper and lower stools was completed, and the double-sided lap machine of the present invention has the constituent features described in the claims as the gist.

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

FIGS. 1 (a) and 1 (b) are explanatory views of a double-sided lapping machine according to the present invention, in which a donut-shaped lower surface plate 1 and an upper surface plate 2 have respective processing surfaces 3
Are arranged so as to face each other, but the centers of the respective surface plates are eccentric to such an extent that the two machining surfaces partially overlap with each other, and they are movably held in a circular space in the circular carrier 4 between the overlapping machining surfaces. The wafer 5 is held, and each surface plate is rotated in the same direction at the same speed to lap the wafer. The carrier 4 is engraved with a spur gear 6 on the outer periphery thereof, and is forcibly rotated by meshing with the drive gears 7 and 8 which are positioned at the centers of the upper and lower surface plates and rotate synchronously. Since the center of the circular cavity is eccentric from the center of the carrier,
During lapping, the wafer oscillates between the processing surfaces to perform uniform lapping. Of course carrier 4 is wafer 5
Since it is thinner, it does not damage each machined surface of the surface plate.

On the other hand, 9 is a correction ring of the lower surface plate 1, which is placed on the processing surface 3'of the lower surface plate which does not overlap the upper surface plate 2 and is held at a fixed position, but is rotatable so that it is the processing surface of the lower surface plate. It rotates with the speed difference between the outer and inner circumferences. The pressing force on the lower surface plate is adjusted by adjusting the weight (not shown) placed on the lower surface plate, and the machined surface of the lower surface plate is corrected to always maintain an appropriate surface.

On the other hand, for the upper surface plate, the two correction rings 10,
11 is pushed up and pressed against the machining surface 3'of the upper surface plate 2 which does not overlap the lower surface plate 1 to make a correction. Both correction rings 10 and 11 require a universal joint, and are rotated by a timing belt (not shown) mounted on a drive pulley (not shown).

The correction surface of the upper platen correction rings 10 and 11 must be higher than the processed surface of the lower platen by the thickness of the wafer, but this height is automatically adjusted and determined by a worm gear (not shown) or the like. If the upper platen is of the fixed spindle type, press the correction ring periodically to correct it.

EFFECTS OF THE INVENTION As described above, in the present invention, the wafer is held by the eccentric carrier and is forcibly driven together with the upper and lower stools, so that the wafer oscillates between the overlapped working surfaces of the upper and lower stools, At the same time, the lapping is performed uniformly, and the working surface is corrected at the same time while lapping the upper and lower platens.Therefore, the lapping machine does not have to be stopped for the correction unlike the conventional method, and the lapping can be performed with high efficiency and high accuracy. The present invention is extremely useful industrially.

[Brief description of drawings]

FIG. 1 is an explanatory view of a lapping machine of the present invention, (a) is a plan view, and (b) is a sectional view taken along the line AA of (a). 1 ... Lower surface plate, 2 ... Upper surface plate, 3, 3 '... Machining surface, 4 ... Carrier, 5 ... Wafer, 6 ... Spur gear, 7, 8 ... Drive gear, 9, 10, 11 …… Correction ring.

Claims (2)

[Claims] 1. A double-sided lapping machine in which a workpiece is held between upper and lower surface plates and both surface plates are rotated to wrap both sides of the workpiece at the same time. They are eccentrically held so as to be overlapped with each other, and thin plate-shaped carriers that hold the workpiece and that are rotated by a rotation drive mechanism are arranged in the mutually overlapping portions, and the thin plate-shaped carriers are placed in the non-overlapping portions of the upper and lower surface plates, respectively. A double-sided lapping machine, characterized in that it is provided with respective correction rings for correcting the working surface of the board. 2. A double-sided lapping machine according to claim 1, further comprising automatic adjusting means for making the correction surface of the upper surface plate correction ring higher than the processing surface of the lower surface plate by the thickness of the workpiece.