JPS60238246A - Vacuum suction block - Google Patents

Abstract

PURPOSE:To make highly accurateness securable without entailing any influence of thermal or humid deformation, etc., by burning and forming a suction block with a porous material base block and an outer edge part being homogeneous to a laminated, nonporous material thin layer and then installing plural grooves or holes reaching to the base block. CONSTITUTION:After a base block 13 having a proper amount of porosity and a top suction part 12 consisting of a nonporous material thin layer having airtightness as well as an outer edge part 14 are solidly burnt, grooves or holes are formed so as to be reached to the base block 13 upon being adjusted to a suction work, and furthermore the top is accurately polished up so as to cause it to be flattened. And, when suction air tekes place by a suctin device, air inside a vacuum suction block 11 is drawn in by suction at grooves 16-18 via an air leading hole 19 so that a wafer 10 is attracted to the top suction part 12 with uniform power and locked thereat, and when polishing is over, the suction device is stopped, releasing the suction of the wafer 10. Next, when cleaning water is fed, it is pressed into the inside of the vacuum suction block 11 from these grooves 16-18 via the air leading hole 19, floating up the wafer 10 from the suction part 12 through grooves or holes 12a and making it easy to separate, and simultaneously swarf or dust in these grooves or holes is washed clean.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vacuum suction table for suctioning and fixing a member to be suctioned, such as a semiconductor wafer glass substrate, onto the suction surface of the table by suction action.

[Background of the invention]

For example, when performing precision polishing on silicon wafers for integrated circuits, or performing precise measurements on glass substrates for liquid crystal display devices, etc., the silicon wafer glass substrate is placed on the bar mounting base by suction action. Adsorption identification. Conventionally, methods for fixing this include forming grooves or holes on the top surface of a metal platform and adsorbing it, or using a porous material in the center as the platform and surrounding the outer edge with non-porous metal. A method of adsorption was used.

[Conventional technology and problems]

However, in the method using a porous material, the porous material is surrounded by a metal with no air permeability, but because the material that makes up the adsorption surface and the material that makes up its outer edge are different, thermal expansion occurs. Due to differences in coefficients and differences in deformation rate due to humidity, the adsorption surface may become distorted, resulting in a thin (.
When polishing a wafer, if you press it from above, it will curve along the distortion, and if you polish it again, when the pressure is released, it will deform and the wafer will bulge out on the surface. This cannot be ignored in wafer polishing, which requires very strict precision (for example, within ±5 μm), and it also has the disadvantage of easily damaging the polishing whetstone and cutter when polishing the suction surface.

Additionally, in order to prevent damage to the whetstone and cutlery as much as possible, it is also possible to use synthetic resin for the outer edge, but in this case, when forming the platform, the resin passes through the porous interior and onto the suction surface. There have been disadvantages in that the suction surface may become uneven or deformed due to protrusion or differences in expansion coefficients.

[Purpose of the invention]

The present invention was developed in view of the drawbacks of the conventional vacuum suction table as described above, and the suction table body is made of a thin layer of non-porous material with no air permeability laminated with a base of porous material. After firing and forming the outer edge of the material - a plurality of adsorption grooves or holes are formed in the nonporous thin layer forming the adsorption surface, and one of the grooves or holes is configured to reach the porous base. This is an attempt to provide a vacuum suction table that is not available in the US.

[Embodiments of the invention]

Next, as an embodiment of the present invention, a vacuum suction table in a polishing apparatus for ultra-precisely polishing silicon wafers with diamond particles using a rotating polishing stone will be described.

In the figure, a cup-shaped rotary polishing grindstone 20 rotates at high speed around a rotating shaft 21. As shown in FIG. A silicon wafer 1'0, which is a member to be attracted, has one surface on which a large number of ICs and LSIs are mounted at predetermined intervals, and one surface must be precisely polished. Reference numeral 11 denotes a vacuum suction table for suctioning and fixing the wafer 10. This vacuum suction table 11 is integrally constructed using an inorganic material such as porcelain or glass. They are ground flat so that there are no gaps between them.

The vacuum suction table 11 is made of, for example, Alundum abrasive grains 6o to 100.
The base 16 is made of coarse particles to obtain an appropriate porosity, and the upper suction part 12 is made of a thin layer of nonporous inorganic material that is also airtight. It is constituted by an outer edge portion 14 of a porous inorganic material. The upper suction part 12 further has a groove or hole 1 so as to reach the base 13.
The manufacturing method of this embodiment, in which a plurality of strips or a plurality of 2a are formed at appropriate intervals over the entire surface and can be sucked when the intake device (not shown) is activated, as described later, will be described as follows. After the base 16 with an appropriate porosity, the upper surface adsorption part 12 and the outer edge part 11i of the airtight thin layer of porosity and no substance are fired together, grooves or holes are formed in the base according to the object to be adsorbed. 16, and then precisely polished to make the soil surface flat.

Base 16, adsorption section 12. By selecting the outer edge portions 14 having the same physical properties but very similar to each other,
It is possible to prevent distortion of the suction surface due to differences in thermal expansion coefficients and differences in deformation rate due to humidity, which are the disadvantages of the prior art described above, and also to prevent the polishing wheel or cutter from being biased to one side when polishing the suction surface. Grooves 16-17-18 for suction and cleaning are formed at the joint between the vacuum suction table 11 and the intermediate member 15, and these grooves 1117-18 are connected to the suction device (
(not shown) and a cleaning device (not shown), and acts for adsorption when the intake device is in operation, and for cleaning when the cleaning device is in operation.

Although not shown in the drawings, it is the same as the conventional structure in that a nozzle, etc. for injecting water or the like for cooling and removing chips is provided corresponding to the polishing location of the rotary polishing wheel 2°.

In such a configuration, when air is taken in by the suction device, the air inside the vacuum suction table 11 is suctioned by the grooves 16-17-18 through the mm through hole 19, so that the wafer 1[] It is suctioned and fixed with a substantially uniform force.

When one polishing is completed, the suction device is stopped and the wafer 10 is released from suction. Next, water for cleaning is sent out from the cleaning device, and this water passes through the conductive hole 19 and is vacuum-adsorbed from the grooves 1117-18. The wafer 1o is press-fitted into the inside of the table 11 through the groove or hole 12a, and is lifted up from the suction part 12 and easily peeled off (
At the same time, the abrasive debris and dirt that have entered the groove or hole 12a are washed away. Effects of the Invention] As is clear from the above description, according to the structure of the present invention, the base constituting the vacuum suction table. , the upper suction part, and the outer edge can be selected from materials that are physically similar to each other, reducing thermal deformation.
It is possible to provide a high-precision vacuum suction table that is not easily affected by changes in humidity and the like. Furthermore, since the above-mentioned base-top suction part and outer edge are physically similar to those described above, even when finishing the suction surface, there is no risk of damaging tools such as the grindstone, and the finish can be uniformly finished. It is possible to provide a vacuum suction table that is extremely effective in practice.

In addition, in this embodiment, it is possible to select and use a material (for example, one with good grindability) that is physically similar to the material of the outer edge of the base-top suction part described above but different from the outer edge. It is.

[Brief explanation of the drawing]

The figure is a sectional view showing one embodiment of the present invention. 11...Vacuum suction table, 12...Top suction part. 12a...Groove or hole, 13...Base-
11i...Outer edge portion-15...Intermediate member. Citizen watch stock size △n10)

Claims (1)

[Claims] A vacuum suction table having a planar suction surface that brings a member to be suctioned, such as a semiconductor wafer, into close contact with it by vacuum suction.One vacuum suction table has a base made of a porous material and a thin layer of non-porous material laminated on the base. 1. A vacuum suction table comprising an upper suction part, an outer edge of a porous material, and a vacuum suction table, wherein the adsorption part has a suction groove or hole deep enough to reach the base.