JP2924934B2 - Etching equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an etching apparatus used for manufacturing a semiconductor integrated circuit, and more particularly to an etching apparatus used for manufacturing a photomask.

[0002]

2. Description of the Related Art A conventional photomask manufacturing process is shown in FIG. That is, as shown in FIG.
A resist 14 serving as a photosensitive agent is applied to a plate on which a single layer film of Cr or a multilayer film 15 made of Cr / CrX OY is formed.
Is applied to a thickness of 3000-6000 angstroms. Next, a desired pattern is drawn using an electron beam exposure apparatus as shown in FIG.

[0003] The plate exposed in this way is set in a developing device, rotated at a speed of 50 to 400 rpm, and sprayed developer is sprayed from a nozzle. As shown in FIG. 14 is dissolved away.

The developed plate is set in an etching apparatus and rotated at a speed of 50 to 400 rpm to spray a sprayed etching solution from a nozzle to etch unnecessary portions of chromium 15 (FIG. 3D). . Finally, the resist 14 is peeled off to complete the photomask (FIG. 3E).

Next, FIG. 4 shows a conventional etching apparatus. This conventional etching apparatus is configured such that a plate 2 mounted on a plate chuck 1 is rotated by a motor 3. A nozzle 4 for spraying the etching solution 5 toward the surface of the plate 2 is provided above the plate 2.
Is provided.

In order to monitor the state of chromium dissolution during etching, a light source 6 and a sensor 7 (light emitting side sensor 7a,
A chromium dissolution monitoring mechanism including a light receiving side sensor 7b), a filter 8, a phototransistor 9, and a transmitted light detector 10 is attached. According to this mechanism, a signal as shown in FIG. 5 is obtained together with the dissolution of chromium, and the end point of the etching can be accurately detected.

[0007]

By the way, there are various types of mask patterns depending on the process to be used. Some mask patterns have a large area to be etched, while others have a small area. In particular, recently, with the miniaturization of patterns, those having an extremely small etching area are increasing. When such a pattern is etched by a conventional etching apparatus,
There has been a problem that the dissolution state of chromium cannot be accurately grasped, and it is difficult to detect the end point of etching on a practical level.

The present invention has been proposed in view of such problems of the prior art, and has as its object to provide an etching apparatus capable of accurately detecting an etching end point regardless of the size of an etching area. .

[0009]

According to the present invention, there is provided an etching apparatus for spray-etching by rotating a plate having undergone a resist coating, exposure and development process, and spraying an etching solution from a nozzle onto the rotating plate. A detection mechanism for distinguishing the presence or absence of a resist on the plate and detecting a portion without the resist as an area to be etched, a monitoring mechanism having an etching end point detection sensor, and monitoring a dissolution state of the area to be etched during etching, and the detection mechanism A driving unit for moving the etching end point detection sensor to an arbitrary position on the plate based on the information from the plate, and the monitor mechanism only when the region to be etched in the plate passes the etching end point detection sensor in synchronization with the plate rotation speed. And a control unit capable of monitoring the dissolution state of the region to be etched by the Etching device is obtained, characterized by. In other words, the present invention provides a mechanism for detecting a region to be etched in a plate and a mechanism for detecting a region to be etched in A control unit that outputs a gate signal only when a region (chromium dissolution unit) passes through the etching end point detection sensor, and a drive system that moves the etching end point detection sensor to an arbitrary position on the plate based on the signal. It is characterized by the following.

[0010]

According to the etching apparatus of the present invention, it is possible to monitor the dissolution of chromium in a pattern having a small area to be etched by concentrating only on the pattern area, thereby realizing accurate end point detection independent of the etching area. it can.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

FIG. 1 is a configuration diagram of an etching apparatus according to the present invention. In this apparatus, in addition to the conventional etching apparatus shown in FIG. 4, the position of the reflected light detector 11, which detects the region to be etched in the plate, the position of the sensor 7 (7a, 7b) and ON / OFF of the end point detection signal are determined. It has a control unit 12 for controlling and a driving unit 13 for moving the sensor 7.

In the etching apparatus of the present invention, the sensor 7a scans the plate 2 sequentially from the end. At this time, light emitted from the light source 6 onto the plate 2 through the sensor 7a is reflected by the plate 2 and is received by the reflected light detector 11. The intensity of the received light is different between the resist existing portion on the plate and the chromium appearing portion where the resist has been removed in the developing step. Therefore, by detecting this difference in light intensity, it becomes possible to specify the chromium appearance portion, that is, the region to be etched. The end point detection sensor 7 moves to the region to be etched thus detected.

Next, the control unit 12 outputs a gate signal only at the moment when the region to be etched passes just below the end point detection sensor 7 by synchronizing with the rotation speed of the plate 2 during etching, and the chromium dissolution state is determined. Monitor. For example, if the plate is to be rotated at 120 rpm, 0.
That is, it is only necessary to output a gate signal every 5 seconds and capture data.

FIG. 2 is a plan view of a part of an etching apparatus showing a second embodiment of the present invention.

Generally, the etching of the plate after development is
The progress does not proceed uniformly over the entire surface of the plate, but non-uniform portions occur at some places. Therefore, in order to accurately detect the end point, it is necessary to monitor the chromium dissolution state at a plurality of locations in the plate. In view of the above, the second embodiment is characterized in that the sensor 7 is installed at a plurality of locations, for example, two locations (two pairs) as shown in FIG.
Therefore, by using the etching apparatus of this embodiment, the end point detection accuracy can be improved by about 50% as compared with the case where the sensor 7 is provided only at one location (one pair) as in the first embodiment.

[0017]

As described above, according to the etching apparatus of the present invention, it is possible to monitor the dissolution of chromium in a pattern having a small area to be etched by focusing only on the pattern area. It is possible to perform accurate end point detection regardless of the magnitude of.

[Brief description of the drawings]

FIG. 1 is a block diagram of a first embodiment of the present invention.

FIG. 2 is a block diagram of a second embodiment of the present invention.

FIG. 3 is a view showing a mask manufacturing process.

FIG. 4 is a block diagram of a conventional etching apparatus.

FIG. 5 is a diagram showing an etching end point detection signal.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Plate chuck 2 ... Plate 3 ... Motor 4 ... Nozzle 5 ... Etching liquid 6 ... Light source 7 (7a, 7b) ... Sensor 8 ... Filter 9 ... Phototransistor 10 ... Transmitted light detector 11 ... Reflected light detector 12 ... Control Unit 13: Drive unit 14: Resist 15: Chromium 16: Quartz substrate

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01L 21/306 H01L 21/3065

Claims (2)

(57) [Claims] An etching apparatus for rotating a plate that has undergone a resist coating, exposing and developing process, spraying an etching solution from a nozzle onto the rotating plate, and performing spray etching. A detection mechanism for detecting a portion having no surface as an etching target area; a monitoring mechanism having an etching end point detection sensor for monitoring a dissolution state of the etching target area during etching; and an etching end point detection sensor based on information from the detection mechanism. And a drive unit for moving the substrate to an arbitrary position on the plate, and monitoring the dissolution state of the region to be etched by the monitor mechanism only when the region to be etched in the plate passes the etching end point detection sensor in synchronization with the plate rotation speed. And a control unit enabling the etching. Grayed apparatus. 2. An etching end point detection sensor, wherein at least two or more etching end point detection sensors are provided in the plate, and a mechanism for monitoring the state of dissolution of the region to be etched during etching is provided to these sensors. A drive unit for moving the plate to an arbitrary position on the plate and a control unit for monitoring the melting state only when the region to be etched in the plate passes the etching end point detection sensor in synchronization with the plate rotation speed are provided. The etching apparatus according to claim 1, wherein: