Polishing body, polishing apparatus, polishing apparatus adjustment method, polished film thickness or polishing endpoint measurement method, and semiconductor device manufacturing method

Abstract

After a hole is formed in a polishing pad, a transparent window plate is inserted into the hole. Here, a gap is left between the upper surface of the transparent window plate and the outermost surface constituting the working surface of the polishing pad. During polishing, the polishing head holding the wafer applies a load to the polishing pad by means of a load-applying mechanism, so that the polishing pad and transparent window plate are compressed. In this case, the system is arranged so that the gap remains constant, and so that a dimension equal to or greater than a standard value is maintained. Since the upper surface of the transparent window plate is recessed from the upper surface of the polishing pad, there is no scratching of the surface of the transparent window plate during dressing. Accordingly, the polishing pad has a long useful life.

Description

BACKGROUND OF THE INVENTION[0001] 1. Field of the Invention[0002] The present invention relates to a polishing body, polishing apparatus, polishing apparatus adjustment method and polished film thickness or polishing endpoint measurement method which are suitable for use in the polishing of semiconductor devices in a method for manufacturing semiconductor devices such as ULSI devices, etc., and to a semiconductor device manufacturing method.[0003] 2. Discussion of the Related Art[0004] As semiconductor integrated circuits have become finer and more highly integrated, the individual processes involved in semiconductor manufacturing processes have become more numerous and complicated. However, the surfaces of semiconductor devices are not always flat. The presence of step differences on the surfaces of semiconductor devices leads to step breakage of wiring and local increases in resistance, etc., and thus causes wiring interruptions and drops in electrical capacitance. Furthermore, in...

AI Technical Summary

Benefits of technology

[0022] The first aspect of the present invention is to solve the above-mentioned problems, and to provide a polishing body which is used in a polishing apparatus that is capable of measuring the polished state by means of light, namely a polishing body that does not cause instability in polishing, a polishing body which has a measurement window that does not require a complicated mechanism, a polishing body that does not suffer from problems such as scratching during dressing, etc., and a polishing body that does not cause instability in the detection of the polishing endpoint in situ, and a polishing apparatus which uses such polishing bodies.

[0024] The second aspect of the present invention is to provide a semiconductor device manufacturing method in which the process is made more efficient by reducing the cost of the polishing process and detecting the polished state with good precision as a result of the use of the polishing apparatus, polishing apparatus adjustment method and polishing endpoint determination method, and which therefore makes it possible to manufacture semiconductor devices at a lower cost than conventional semiconductor device manufacturing methods.

Problems solved by technology

As semiconductor integrated circuits have become finer and more highly integrated, the individual processes involved in semiconductor manufacturing processes have become more numerous and complicated.

However, the surfaces of semiconductor devices are not always flat.

The presence of step differences on the surfaces of semiconductor devices leads to step breakage of wiring and local increases in resistance, etc., and thus causes wiring interruptions and drops in electrical capacitance.

Furthermore, in insulating films such step differences also lead to a deterioration in the withstand voltage and the occurrence of leaks.

As a result, the focal depth of the projection lenses used in such semiconductor exposure apparatuses has become substantially shallower.

Furthermore, because of variations in the surface conditions of the polishing body, the polishing rate drops with the number of wafers processed, and there are differences in the polishing rate due to individual differences between polishing bodies, etc.

Accordingly, it is difficult to determine the endpoint of polishing by performing a specified amount of polishing using time control.

Accordingly, this polishing work results in increased costs, and is therefore undesirable for stabilizing the semiconductor device manufacturing process and reducing production costs.

However, in the case of silicon wafers having complicated patterns, there is little variation in the material of the object of polishing.

Accordingly, there are cases in which it is difficult to ascertain the endpoint.

It is difficult to measure the film thickness using a method in which the endpoint is ascertained by in-situ measurement of the motor torque or vibration, etc.

In cases where no window is installed, the slurry, water and other components used in cleaning, etc., leak from this area.

As a result, a complicated mechanism is required, so that the apparatus becomes complicated.

However, in the case of foam polyurethane polishing pads, the polishing agent causes clogging, so that the polishing characteristics are unstable.

Since this material generally differs from the material of the polishing body in terms of mechanical properties, there is a serious danger that this material will cause differences in the polishing rate, polishing non-uniformities, and scratching.

Furthermore, problems also arise from the window becoming scratched so that it becomes optically opaque when the polishing body (polishing pad) is cut away during the above-mentioned dressing.

As a result, measurements become impossible.

Specifically, if there is a step difference between the surface of the polishing body and the surface of the window on the side of the object of polishing, the polishing agent will accumulate in the opening part, thereby causing attenuation of the measurement light.

However, in cases where an anti-reflection film is formed on a window that is manufactured from a soft material, cracks are formed in the anti-reflection film as a result of the bending of the window.

Furthermore, since the glass transition temperature of the window is low, the window may expand or contract as a result of temperature changes, so that cracks are formed in the anti-reflection film.

Accordingly, in cases where the window is manufactured from a soft material, formation of an anti-reflection film is difficult.

Accordingly, the window that is installed undergoes deformation, thus causing optical distortion.

As a result of this distortion, the window acts as a lens, etc., so that that detection of the polishing endpoint and measurement of the film thickness become unstable.

Furthermore, the problem of erroneous measurement arises in cases where the polished film thickness or polishing endpoint is measured without a constant thickness of the polishing agent between the window and the object of polishing.

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