JPS60122945A - Photomask processing end point detecting device - Google Patents

Abstract

PURPOSE:To raise a detection accuracy of a photomask processing end point by irrdiating a detecting light of a projector to a reflecting object buried in a sample placing base, detecting a transmittivity of a photomask of a reflected light, and controlling the photomask processing basing on this detected value. CONSTITUTION:A photomask is placed on a transparent sample placing base 10, a treating liquid is dropped from a drop nozzle 6, and the placing base is rotated. When etching of a chrome film 9 advances, and the chrome film 9 is eliminated from on the surface of the photomask, a detecting light 14 transmits through the photomask, and reaches a reflecting object in the sample placing base. A reflected light 30 reflected by the reflecting object transmits through the photomask again and reaches a photodetector 5. The photodetector 5 detects an optical transmittivity of the photomask and converts it to an electric signal, etc. This electric signal is connected with a processing time setting part 21 through an optical transmittivity detecting part 20. Information of this processing time is connected with a processing control part 22, this control command is connected with a driving control part 23 and a treating liquid supply part 24, and the processing end point is detected with a high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an end point detection apparatus for photomask processing, particularly etching.

[Background technology]

In the manufacturing process of semiconductor devices, one method is to form a pattern on a photomask. That is, an etching liquid is dropped onto the surface of the photomask, and as the photomask mounting table rotates, lines of etching liquid spread across the entire surface of the photomask. For example, the etching solution erodes the chromium film leaving behind the portions covered with the resist film, thereby forming a desired pattern on the photomask.

In such an apparatus, it is necessary to observe the progress of etching and accurately determine the end of etching.

As a device for detecting the end point by visual observation or automatically determining the end point, for example, an end point detection device as shown in FIG. 1 has been proposed.

This end point detection device includes a light projector 4 located below the photomask 10.
and a light receiver 5 are provided above the photomask 10, and the detection pattern 11 provided on the outer circumference 13 of the photomask is irradiated with detection light 14 as shown in FIG. 2 and wcB, and the transmittance of the detection light is measured. It is configured to determine that the detected point is the end point.

In other words, the chromium film 9 on the photomask 10 has a detection pattern for determining the end point [prepared by exposure].
The detection light 13 is irradiated toward the detection chisel turn, and the chromium! When the photoresist 8 on the photoresist 119 is etched, the detection light comes to be transmitted through the photomask, and the light transmittance increases. This light transmittance? By monitoring and noting, for example, a sudden increase in the transmittance, it is possible to determine the end point.

However, in such an end point detection device, as shown in FIG. 3, it is necessary to provide a detection pattern 11), and it takes a lot of time to expose and provide it, for example, every 10 liters. was spending.

In addition, since the detection pattern is provided on the photomask and the light transmittance is measured while the mounting table rotates, the detection
3t and 14 collide with the mounting table, causing a phenomenon of diffuse reflection. This scattered light enters the light receiver 5 and becomes a nozzle in the light receiver, resulting in a disadvantage that the accuracy of end point determination deteriorates.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a photomask processing end point detection device that can eliminate inaccuracies in end point determination and accurately determine the end point.

The above and other objects and novel features of the present invention include:
It will become clear from the description of this specification and the accompanying drawings.

[Summary of the invention]

A brief overview of typical inventions disclosed in this application F! 8Jj′ is as follows.

In other words, a light emitter/receiver is installed above the sample mounting table, and the detection light of the projector is irradiated onto a reflecting object buried within the sample mounting table (
2. The transmittance of the reflected light through the photomask is detected, and the photomask processing can be controlled based on this detected value.

〔Example〕

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

FIG. 4 shows an embodiment of the photomask processing end point detecting device according to the present invention. Reference numerals 1 and 15 constitute a photomask processing tank, and the lid 15 is transparent because the detection light 14 passes therethrough.

A sample mounting table is provided inside the processing tank, and the mounting table is rotated by a rotating shaft 2. The rotating shaft 2 passes through the bottom wall and is connected to the drive body 3. There is a dripping nozzle 6 for dripping the processing liquid between the mounting table and the lid, which is connected to the processing liquid supply section 17, and a drain lower at the bottom of the processing tank so that the processing liquid can be discharged to the outside of the tank. It was opened in . A light emitter/receiver 16 is provided above the sample mounting table and outside the tank. A light projector 4 emits detection light 1 consisting of a suitable light beam such as a laser.
4 is irradiated toward the center of the photomask. A reflective object (corner cube) is buried approximately in the center of the sample mounting table at an angle that reflects the light beam from the projector to the receiver 5. The light receiver 5 is composed of, for example, a sensor, and converts an inspection value corresponding to the amount of light transmitted through the photomask (light transmittance) into an electrical signal, etc., and controls the control mechanisms 20 to 24.
I am supposed to contact you.

Next, I will explain how it works.

First, a photomask is placed on a transparent sample mounting table 10, a processing liquid is dropped from the dripping nozzle 6, and the photomask is rotated via a driver 3 connected to the rotating shaft 2 of the mounting table. Detection light 14 from the projector 4 is reflected by a reflective object 2 provided approximately at the center of the sample mounting table.
5, and the reflected light 30 is caught by the light receiver 5. In order to form a desired pattern on the photomask of the mounting table, the chromium film 9 is first etched with a processing solution. At this point, the detection light 14 hardly reaches the reflective object 25 due to the chromium film 9. Therefore, the light receiver 5 which receives the totally reflected light receives almost no light.

Etching of the chromium film 9 by the treatment liquid progresses,
When the chromium film 9 disappears from the surface of the photomask, the detection light 14 incident on the photomask is transmitted through the photomask because there is no chromium film 9, and reaches the reflecting object. The reflected light 30 that is then reflected by the reflective object passes through the photomask again and reaches the light receiver 5.

As shown in FIG. 5, the reflecting object has a home base shape, and has a structure in which the incident light 27 is reflected in a fixed direction, and the reflected light 28 is reflected in parallel to the incident light 27.

The light receiver 5 is composed of a sensor, etc., and detects the light transmittance of the photomask of the reflected light 3o, and converts this detected value into an electrical signal or the like. This electrical signal is communicated to the light transmittance detection section 20 and then to the processing time setting section 21. This processing time information is communicated to the processing control section 22, and this control command is communicated to the drive control section 23 and the processing liquid supply control section 24.

In this way, by sensing the light transmittance, it is possible to automatically detect the processing end point, that is, the processing time.

〔effect〕

By embedding a reflective object in the sample mounting table and detecting the photomask transmittance of the reflected light, it is possible to accurately determine the end point of photomask processing.

Although the invention made by the present inventor has been specifically explained above based on examples, it goes without saying that the present invention is not limited to the above-mentioned examples, and can be modified in various ways without departing from the gist thereof. Nor.

[Application field]

In the above explanation, the invention was mainly applied to photomask etching technology, which is the field of application behind the invention made by the present inventor, but the invention is not limited to this, and is not limited to this. Can be applied to things.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a conventional etching end point determination device, FIGS. 2 and 3 are partial schematic explanatory diagrams of the conventional example, and FIG. 4 is a schematic configuration diagram of a photomask processing end point detection device according to the present invention. , FIG. 5 is a partially enlarged explanatory diagram according to the present invention. 1... Processing tank, 2... Rotating shaft, 3... Drive body, 4
... Emitter, 5... Light receiver, 6... Dripping nozzle,
7... Discharge port, 8... Photoresist film, 9... Chrome film, 10... Photomask, 11... Detection pattern, 12... Photomask pattern, 13... Photomask outer periphery, 14.=detection light, 15...lid body, 16
... Light emitter/receiver, 17... Processing liquid supply section, 18...
Bearing, 19... Bottom wall, 20... Light transmittance detection section, 2
1... Processing time setting section, 22... Processing control section, 23
...-Drive control section, 24... Processing liquid supply control section, 25
...Reflecting object (Konakiep), 26...Sample mounting table.

Claims (1)

[Claims] 1. A photomask processing end point detection device consisting of a rotatable sample mounting table and a light emitter/receiver for detecting the transmittance of the photomask, wherein a reflective object is buried approximately in the center of the sample mounting table, and On the other hand, the photomask processing end point detection method includes a mechanism for emitting detection light from the light projector, detecting the transmittance of the photomask using the reflected light from the reflecting object, and controlling the photomask processing based on the detected value. Device.