JPS63254733A - Equipment for manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To perform a process for retaining the thickness of a film to be etched at a desired value by providing a film thickness measuring unit or ellipsometer for measuring the remaining thickness of an insulating film or a semiconductor film during etching to arbitrarily monitor the advancement of the etching. CONSTITUTION:A laser light emitted from a light emitting unit 7 of an ellipsometer E is reflected on a semiconductor substrate 5 placed on a stage 6 in a chamber 2 through a window 4, radiated from the opposite side of the window 4, and introduced into an ellipsometer photodetector 3. The thickness of the etched film on the substrate 5 is sampled by the ellipsometer E during sampling. The target values of the sampled film thickness and the remaining film thickness are compared by a comparator 14, and when they arrive at the object value, the etching is finished. Thus, the thickness of the remaining film of the etching can be accurately controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor device manufacturing apparatus, and particularly to an etching apparatus.

(Prior Art) This type of etching apparatus etches the entire surface of an insulating film or a semiconductor film such as polysilicon on a semiconductor substrate, and it is necessary to stop etching when a set etching amount is reached. As an etching device, 1
For example, a device that detects the end time of etching by using changes in the spectrum in plasma during and after etching in a dry etching process, or a device that detects the end time of etching by using changes in infrared transmittance in a wet etching process. There are devices that do this.

[Problem that the invention seeks to solve]

Since the conventional etching apparatus described above utilizes changes in the spectrum or transmittance during and after etching, it is not possible to monitor the progress of etching at any time by measuring the remaining film thickness of the film to be etched. This method has the disadvantage that it cannot be used in a process where the entire surface of the film to be etched is etched to a certain thickness, for example, several hundred layers.

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor device manufacturing apparatus that solves the above-mentioned problems.

[Differences between the invention and the prior art]

In contrast to the conventional etching apparatus described above, the apparatus of the present invention has a function of measuring the remaining film thickness of the film to be etched during etching, so that the progress of etching can be monitored at any time and the desired thickness of the film to be etched can be determined. It has the original content of making it possible to create a process that leaves the material as thick as possible.

[Means for solving problems]

The present invention provides an apparatus for etching the entire surface of an insulating film or a semiconductor film such as polysilicon on a semiconductor substrate, which is equipped with a film thickness measuring device or an ellipsometer for measuring the remaining film thickness of the insulating film or semiconductor film during etching. This is a semiconductor device manufacturing apparatus characterized by:

〔Example〕

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

(Embodiment 1) FIG. 1 shows an embodiment in which the present invention is applied to a dry etching apparatus. In FIG. 1, this type of dry etching apparatus has a stage 6 installed at the bottom of a chamber 2, an upper electrode 1 placed above the stage 6, and a semiconductor substrate 5 set on the stage 6. Then, an etching process gas is sent into the chamber 2, and this gas is turned into plasma by a voltage applied between the upper electrode 1 and the stage 6, and the semiconductor film such as the insulating film on the substrate 5 is completely covered with this plasma-turned gas. etching.

In this embodiment, as shown in FIG. 1, windows 4, 4 made of quartz or the like are provided on opposite side walls of the chamber 2, respectively.

The light emitting part 7 of the ellipsometer irradiates the substrate 5 with laser light from outside the chamber through the window 4, and the light receiving part 3 of the ellipsometer receives the laser light reflected by the substrate 5 through the window 4. It is equipped with an ellipsometer E for measuring the remaining film thickness, and a comparator 14 that compares the sampled film thickness with a target value of the remaining film thickness and outputs an etching stop signal when the values match.

Laser light emitted from the light emitting section 7 of the ellipsometer E passes through the window 4, is reflected on the surface of the semiconductor substrate 5 placed on the stage 6 in the chamber 2, and exits from the window 4 on the opposite side to the ellipsometer light receiving section 3. enter. This ellipsometer E
The thickness of the film to be etched on the semiconductor substrate 5 is sampled during etching. A comparator 14 compares the sampled film thickness with the target value of the remaining film thickness, and when the target value is reached, the etching is terminated. By using this method, it is possible to accurately control the thickness of the remaining film after etching.

(Embodiment 2) Figure 2 shows an embodiment in which the present invention is applied to an apparatus that performs a wet etching process using an etching solution 9 in an etching tank 8. In this embodiment, a window 12 is installed in an etching tank 8. Then, through this window 12, the remaining film thickness of the film to be etched on the surface of the semiconductor substrate 11 is measured using a film thickness measuring device 13 using spectroscopy.

This measured value and the target residual film thickness are compared by a comparator 14,
Etching ends when the target value is reached. 10 is a carrier that supports the substrate 11.

〔Effect of the invention〕

As explained above, the present invention makes it possible to precisely control the remaining film thickness by sampling the remaining film thickness of the film to be etched during etching.

By using this method, in a planarization technique such as an etch-back method, the remaining film thickness can be kept constant despite changes in the etching rate of the etching device.

In addition, if the etching gas or etching solution damages the underlying layer after the etching film is etched during full-surface etching, the etching film may be slightly left remaining, for example, after etching is stopped after several hundred etching steps. By changing the etching gas and etching solution, it is possible to etch the remaining film without damaging the underlying layer, which has the effect of improving the stability of the process.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention in a dry etching process, and FIG. 2 is a longitudinal sectional view showing an embodiment of the invention in a wet etching process. 1... Upper electrode 2... Chamber 3.
...Light receiving part of ellipsometer 4,12...Window 5.
11...Semiconductor substrate 6...Stage 7...
・Light emitting part of ellipsometer E...Ellipsometer 8...Etching tank 9...Etching liquid 10...Carrier 13...Film thickness measuring device Fig. 2

Claims (1)

[Claims] (1) An apparatus for etching the entire surface of an insulating film or a semiconductor film such as polysilicon on a semiconductor substrate, which is equipped with a film thickness measuring device or ellipsometer that measures the remaining film thickness of the insulating film or semiconductor film during etching. A semiconductor device manufacturing device characterized by: