JPH07167631A - Substrate cleaning equipment - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a substrate cleaning apparatus having a function of detecting occurrence and progress of abrasion of a substrate pattern. According to the present invention, in a substrate cleaning apparatus for cleaning a substrate having a fine pattern formed on its surface, a substrate cleaning unit for cleaning the substrate, and the substrate surface after cleaning the substrate by the substrate cleaning unit. And a pattern inspection means for inspecting the wear of the pattern.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate cleaning apparatus, and more particularly to a cleaning apparatus for removing foreign matters (fine dust, stains or oil) attached to a glass substrate such as a reticle or a photomask used in a semiconductor manufacturing process. .

[0002]

2. Description of the Related Art If foreign substances such as dust adhered to a glass substrate such as a reticle or a photomask are left as they are, these foreign substances are transferred onto the wafer and cause defects in the manufactured wafer. Since various kinds of contaminants adhere to the substrate, various cleaning methods have been proposed according to the kind of adhered contaminants. For example, as a method for removing inorganic contaminants such as metal oxides and dust, there are a brush scrubbing method using a pair of rotating brushes and an ice scrubbing method in which clean ice particles are sprayed onto a substrate surface under pressure. In either method, in principle, contaminants on the substrate surface are directly removed by physical action.

As described above, in the cleaning apparatus which performs the cleaning process by applying the physical force to the surface of the glass substrate, the pattern formed on the substrate may be worn or peeled off by repeating the cleaning of the substrate. is there. Here, the abrasion of the pattern means that the edges of the lines forming the pattern are partially missing, and the peeling of the pattern means that the lines forming the pattern are peeled off from the substrate over the entire width thereof. .

In particular, since the degree of integration of semiconductors has increased and the patterns have become finer in recent years, the line width of the patterns deposited by chromium, for example, has become smaller, and the patterns are worn or peeled (hereinafter simply referred to as "wear"). ) Is more likely to occur. In the conventional substrate cleaning apparatus, by devising the chemicals, the cleaning liquid, and the cleaning method used in the cleaning process, the substrate pattern is prevented from being worn as much as possible.

[0005]

SUMMARY OF THE INVENTION In the prior art,
Even if you devise so that the wear of the board pattern does not easily occur,
As the cleaning of the substrate is repeated, the abrasion of the pattern formed on the substrate is generated and progresses to some extent. However, the conventional substrate cleaning apparatus does not have a function of detecting the occurrence and progress of wear. On the other hand, if projection exposure is performed using a substrate whose pattern wear has progressed beyond a predetermined level, it causes defects in the manufactured wafer.

As described above, since the conventional substrate cleaning apparatus does not have the function of detecting the abrasion state, the projection exposure is performed by using the substrate in which the abrasion of the pattern has already progressed beyond the predetermined degree by the cleaning procedure. There was a possibility. For this reason, there is an inconvenience that a defective wafer is manufactured and the throughput is remarkably reduced.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a substrate cleaning apparatus having a function of detecting the occurrence and progress of abrasion of a substrate pattern.

[0008]

In order to solve the above problems, in the present invention, in a substrate cleaning apparatus for cleaning a substrate having a fine pattern formed on its surface, a substrate cleaning means for cleaning the substrate is provided. And a pattern inspecting unit that inspects a pattern on the surface of the substrate for abrasion after the substrate is cleaned by the substrate cleaning unit.

According to a preferred embodiment, the inspection means is
A detection unit for detecting the pattern data of the substrate and a comparison unit for comparing the pattern data of the substrate detected by the detection unit with the reference pattern data stored in advance are provided.

[0010]

As described above, by detecting the pattern data of a specific substrate and comparing the detected pattern data with the pattern data in the initial state (for example, the state before the first cleaning) of the substrate, the substrate pattern It is possible to detect the wear state of. Specifically, for example, by imaging the pattern of the board, the image information of the board pattern in the initial state and the image information of the board pattern at the present time,
By comparing each pixel, it is possible to detect the occurrence and progress of the abrasion of the substrate pattern.

The pattern to be imaged may be a part or the whole of the pattern to be projected and exposed, or is a wear inspection pattern formed in a specific region of the substrate for inspecting the wear state. Good. Here, the wear inspection pattern is formed under the same conditions as the pattern to be projected and exposed. As a result, since the occurrence and progress of wear almost match between the wear inspection pattern and the pattern to be projected and exposed, the wear state of the pattern to be projected and exposed is detected by detecting the wear state of the wear and inspection pattern. The state can be detected indirectly.

In general, the occurrence and progress of wear depend on the wear resistance of the pattern formed on the substrate, the number of times of cleaning, the cleaning process and the like. That is, when a specific cleaning process is applied to a specific substrate, wear progresses as the number of cleaning times increases. Therefore, it is preferable to count the number of times of cleaning the substrate and compare the detected pattern data with the initial pattern data only when the number of times of cleaning exceeds a predetermined number determined depending on abrasion resistance, cleaning process and the like. .

[0013]

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a diagram schematically illustrating the configuration of a substrate cleaning apparatus according to an embodiment of the present invention. The apparatus of FIG. 1 has a detection tank 1 for detecting pattern data of a substrate, a cleaning tank 2 for cleaning by applying a physical force to the substrate surface, a drying tank 3 for drying the substrate, and data storage. And a data processing system 4 for processing.

The illustrated apparatus further includes a transfer system 5 for transferring the substrate to the detection tank 1, the cleaning tank 2 and the drying tank 3 according to a predetermined processing step. Each processing tank 1
To 3, the data processing system 4 and the transfer system 5 are housed in one cleaning chamber provided with the clean unit 6. In the detection tank 1, a CCD camera 11 as an image pickup means is provided.
Further, a symbol discriminator 12 is provided for reading a symbol attached to the substrate and discriminating each substrate.

A plurality of nozzles 22 for injecting the cleaning liquid and a pair of nylon brushes 21 positioned below the nozzles 22 are provided in the cleaning tank 2.
Thus, the cleaning tank 2 constitutes a brush scrubbing tank. Further, in the drying tank 3, a heater 31 and a container 34 positioned above the heater 31 are provided.
In the container 34, isopropyl alcohol liquid (IPA)
32 are accommodated. In this way, the drying tank 3 is IPA
It constitutes a drying tank.

On the other hand, the data processing system 4 stores the number of times of cleaning each substrate, abrasion resistance, initial state pattern data and the like, and a computer 44 for processing each data, and for displaying the output of this computer 44. And an indicator 45 of. The data processing system 4 may be provided outside the cleaning chamber. Finally, the substrate transfer system 5 supports a glass substrate 7 such as a reticle on which a pattern is formed by chromium vapor deposition, and a holding metal fitting 8 that can move in the vertical direction in the figure, and a guide arranged horizontally in the figure. 10 and holding metal fittings 8
And a transporting unit 9 for moving back and forth along the guide 10 and also in the vertical direction in the figure. Thus, the substrate 7 to be cleaned can be transported into a desired processing tank by the action of the transport system 5.

The operation of the substrate cleaning apparatus of this embodiment having the above construction will be described. For example, the substrate 7 to be cleaned taken out from a storage means (not shown) such as a reticle cassette moves to above the cleaning tank, that is, the brush scrubbing tank 2, while being held by the holding metal fitting 8. Then, by the action of the transport unit 9, the holding metal fitting 8 and thus the substrate 7 descends to a predetermined position in the brush scrubbing tank 2. In the brush scrubbing tank 2, a suitable cleaning liquid such as pure water is sprayed onto the surface of the substrate 7 through the nozzle 22 at a constant pressure.

The substrate 7 is further moved downward by the action of the transport unit 9 and is inserted between the pair of rotating nylon brushes 21. In this way, the contact frictional force of the pair of nylon brushes 21 is applied to the entire surface of the substrate 7 to remove the foreign matter attached to the substrate. The substrate 7 cleaned in the brush scrubbing tank 2 is wet with the cleaning liquid. For this reason,
The drying process is performed in the drying tank, that is, the IPA drying processing tank 3. In the IPA drying treatment tank 3, the isopropyl alcohol liquid 32 in the container 34 is vaporized by the action of the heater 31, and the isopropyl alcohol vapor filled portion 33 is formed in the upper region of the container 34.

The substrate 7 is transferred to the IPA by the action of the transport system 5.
It is conveyed above the drying treatment tank 3. Next, the substrate 7 descends and is immersed in the isopropyl alcohol vapor-filled portion 33. Here, the water adhering to the surface of the substrate 7 is combined with the isopropyl alcohol gas and volatilized. Thus
The drying process of the substrate 7 is completed.

The cleaned substrate 7 moves above the detection tank 1 by the action of the transport system 5, and then descends by the action of the transport unit 9 to move the CCD camera 11 and the symbol discriminator 12.
Stop in front of. An identification pattern in which identification information is encoded is formed on the substrate 7, and the symbol identification device 12 reads this identification pattern. The identification information read by the symbol identifier 12 is sent to the computer 44.

A wear inspection pattern is formed in a specific region of the substrate 7 for inspecting the wear state. By the way, the wear inspection pattern has the same condition (material,
Line width, forming method, etc.). So CCD
The camera 11 captures an image of the wear inspection pattern of the substrate 7. The image information captured by the CCD camera 11 is
It is sent to the computer 44.

The computer 44 retrieves information on the number of times the substrate is cleaned, abrasion resistance, etc., based on the identification information sent from the symbol identifier 12. If the number of times of cleaning is large in consideration of the abrasion resistance of the substrate, a warning message is displayed on the display unit 45. Next, the computer 44 searches the pattern data of the wear inspection pattern in the initial state of the corresponding board based on the identification information sent from the symbol classifier 12. The pattern data in the initial state is, for example, image information captured by the CCD camera 11 before the first cleaning. The wear state is inspected by comparing the searched image information in the initial state with the image information detected by the CCD camera 11 at the present time, and when the occurrence and progress of the wear are recognized, a warning message is displayed on the display unit 45. To do.

As described above, if the abrasion inspection processing is completed and it is recognized that the progress of abrasion exceeds a predetermined degree, it is discarded without being subjected to projection exposure. In this way, it is possible to avoid projection exposure using a substrate having a defect and improve throughput. In addition, in the above-described embodiment, the example in which the wear inspection is performed after the substrate cleaning process is shown, but the wear inspection may be performed before and after the substrate cleaning process.

Further, in the above-mentioned embodiment, an example in which the wear inspection pattern is imaged to detect the pattern data is shown, but a part or all of the pattern to be projected and exposed may be imaged, or other. A part or all of the wear inspection pattern or the pattern to be projected and exposed may be detected by any suitable means. Further, in the above embodiment,
Brush scrubbing as a cleaning method and I as a drying method
Although the PA dry treatment method is applied, the present invention can be applied to other suitable cleaning treatments with or without a dry treatment.

[0025]

As described above, according to the present invention, it is possible to appropriately detect the abrasion state of the substrate pattern while referring to the abrasion resistance of the substrate to be cleaned, the number of times of cleaning, etc.
It is possible to reliably avoid subjecting a substrate having a so-called defect, which has already been worn over a predetermined degree, to projection exposure. As a result, the throughput is significantly improved.

[Brief description of drawings]

FIG. 1 is a diagram schematically illustrating a configuration of a substrate cleaning apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 1 Detection Tank 2 Cleaning Tank 3 Drying Tank 4 Data Processing System 5 Transport System 6 Clean Unit 7 Substrate 8 Holding Metal 9 Transport Section 10 Guide Rail 11 CCD Camera 12 Symbol Identifier 22 Nozzle 23 Nylon Brush 31 Heater 32 Isopropyl Alcohol 44 Computer 45 display

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H01L 21/66 J 7630-4M

Claims (8)

[Claims] 1. A substrate cleaning apparatus for cleaning a substrate having a fine pattern formed on a surface thereof, comprising: a substrate cleaning unit for cleaning the substrate; and a pattern on the substrate surface after cleaning the substrate by the substrate cleaning unit. And a pattern inspecting means for inspecting the abrasion of the substrate. 2. The inspecting device for detecting pattern data of the substrate and comparing the pattern data of the substrate detected by the detecting device with reference pattern data stored in advance. The substrate cleaning apparatus according to claim 1, further comprising a comparison unit. 3. The substrate cleaning apparatus according to claim 2, wherein the detection means is an image pickup means for picking up an image of the pattern of the substrate. 4. The substrate cleaning apparatus according to claim 3, wherein the imaged pattern is a wear inspection pattern formed in a specific region of the substrate for inspecting the wear of the substrate. 5. The substrate cleaning apparatus according to claim 4, wherein the wear inspection pattern is formed outside the area to be projected and exposed under the same conditions as the pattern to be projected and exposed. 6. The pattern data stored in advance is
The substrate cleaning apparatus according to any one of claims 2 to 5, wherein the pattern data is pattern data detected by the detecting unit before the first cleaning is started. 7. The substrate cleaning apparatus according to claim 2, wherein the detection unit detects pattern data of a substrate whose cleaning frequency exceeds a predetermined number. 8. A display means for displaying the abrasion resistance of the pattern of the substrate, the number of times of cleaning the substrate, and the like in addition to the abrasion state of the pattern of the substrate to be cleaned. The substrate cleaning apparatus according to any one of claims 2 to 7.