JPS60177624A - Processor - Google Patents

Abstract

PURPOSE:To contrive to save cost of process and a material by a method wherein existance of adhesion of a foreign matter on a member to be applied or a member finished with application is detected automatically to remove a product of inferior quality. CONSTITUTION:Light radiated from a laser light source 23 is reflected by a high speed scanning mirror 24, and projected to a foreign matter 22 on a mask plate 21. Reflected light from the foreign matter is condensed 25, detected 26 to be expressed by a binary value 27, and counted 28. The counted value is compared 29 with a set value, and when it exceeds the set value, it is removed as an article of inferior quality. When the automatic selection process thereof is provided before and behind of a resist application process or on one side thereof, yield of the members finished with application is enhanced, and further, selection can be performed rapidly and correctly, and productivity is also enhanced.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to processing technology, and in particular to coating mask plates and wafers used in the manufacture of semiconductor integrated circuits with photoresist, electron beam resist, etc. The present invention relates to an effective technology that can be used to automatically sort out items with foreign substances such as dust attached thereto.

[Background technology]

In the photolithography process of mask plates and wafers used in semiconductor integrated circuits (LSI, etc.), after cleaning the mask plate and uninot, photoresist coating - blebake - exposure - development - postbake -
Scum removal - etching - resist removal - inspection - modification (
Only the mask will undergo a process step (for example, to remove external defects, excess ROM, etc.). Masks and wafers are inspected only at the final stage after going through this series of processes, so if a mask or wafer is found to be unusable (defective) due to foreign matter attached to it at this stage, it will be Processing costs and materials are wasted. Moreover, this becomes a problem as more and more defective products are produced due to the adhesion of such foreign matter.

Therefore, in the resist coating process after cleaning, the present inventors
The resist blown away by the resist coating spinner adheres to the cup surrounding the spinner, and small pieces of that adhered material may fall from the cup and adhere to the resist coating mask plate or wafer, or the resist may be coated in the atmosphere. Focusing on the problem of dust and other foreign matter easily adhering to the cup, we first created an air flow in the vertical direction around the spinner of the resist coating device to allow small pieces of resist attached to the cup to fall and coat the resist. After pre-baking after resist application, visual inspection was conducted to prevent it from adhering to the mask plate or wafer.
We devised a method in which we would take out those with a fair amount of foreign matter and rewash them, and then send the good ones to the next process.

However, even if such a method is employed, it is not possible to completely prevent foreign matter from adhering to the mask plate or wafer in the resist coating apparatus. Furthermore, even if visual inspection is used to sort out items with a lot of foreign matter attached, there are problems such as requiring skill and erroneous judgments may be made, and the inspection is time-consuming and undesirable from the perspective of improving productivity. was revealed by the present inventor. Furthermore, due to the quality required for masks and wafers, we have thought about reducing defects as much as possible. Furthermore, the present inventor has revealed that defects often occur due to adhesion of foreign matter during resist coating.

[Purpose of the invention]

An object of the present invention is to very quickly and accurately sort out coated members to which foreign matter such as dust has adhered or coated members (mask plates and wafers) at an early process stage, and to Alternatively, the coated parts (mask plates and wafers) can be supplied to subsequent processing steps, improving the yield of coated parts (masks and wafers) and significantly reducing processing costs and material waste. The objective is to provide processing technology that

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 is as follows.

That is, for example, after cleaning the member to be coated with the cleaning device, before applying the coating material to the member to be coated with the coating device, and at least after applying the coating material to the member to be coated with the coating device, the automatic inspection device Automatically inspects whether foreign matter such as dust is attached to the member to be coated or the coated member, selects pass/fail very quickly and accurately, and supplies non-defective products to subsequent processing steps, The yield of finished masks and wafers can be improved, and processing costs and material waste can be significantly reduced.

〔Example〕

The present invention applies to semiconductor integrated circuits (for example, LSI, VLSI)
This is applied to the mask creation process in manufacturing and the resist treatment process during sea urchin processing, as shown in Figure 1.

This will be explained in detail below using FIG.

FIG. 1 shows an example of a photoresist processing process for a mask plate or wafer to which the present invention is applied, and 1 is a cleaning process in which the mask plate or wafer is cleaned using brush cleaning, chemical cleaning, plasma cleaning, etc. A cleaning device is used. 2 is an automatic inspection process,
In this automatic inspection process 2, the automatic inspection device automatically detects foreign substances such as dust that were attached from the beginning but could not be removed in the cleaning process 1, and selects mask plates or wafers with a lot of foreign substances attached and unloads them. The products are stored in a storage room, separated from non-defective products, and returned to cleaning step 1 for re-cleaning and regeneration. Also, in automatic inspection process 2, check whether there is any foreign matter attached.
Alternatively, those with less adhesion and judged to be good are transported to the next step, resist coating step 3, where photoresist is coated by a resist coating device. The resist coating device uses a rotary coating machine (coating spinner) to drop the resist solution onto the mask plate or wafer placed on the coating spinner, first rotate the coating spinner at a low speed (for example, 10 rpm), and then High speed rotation (
For example, 2000 to 3000 rpm). This allows excess resist solution to be dispersed by centrifugal force, creating a uniform thin film. In this resist coating device, as mentioned above, airflow is provided in the vertical direction around the coating spinner, so that small pieces of resist that are scattered and attached to the cup surrounding the spinner fall and adhere to the mask plate or the surface of the wafer. In addition, since coating is performed in the atmosphere, although measures are taken to prevent foreign matter such as atmospheric dust from adhering to the mask plate or wafer surface, it is difficult to ensure completeness and dust and other foreign matter may adhere to the wafer surface. . Further, after the photoresist is removed from the resist coating device, dust in the atmosphere tends to adhere to the coated adhesive surface. The photoresist coated by the resist coating device in resist coating step 3 is first prebaked in a baking oven to increase the adhesion between the resist film and the base. After this pre-bake step 4, in the automatic inspection step 5, the above-mentioned automatic inspection device automatically inspects the mask plate or wafer coated with resist to see if there is a lot of foreign matter attached to it, sorts it out, and unloads the non-defective products. and transported to the next step, for example, exposure step 6. - Male non-defective products will be stored in another unloader and returned to cleaning step 1, where they will be re-washed and recycled. After the exposure step 6, a series of process steps including a development step 7, a bossed paint step 8, a scum removal step 9, an etching step 10, a resist removal step 11, and an inspection step 12 are performed. After the mask-only inspection step 12, a correction step for appearance defects, excess ROM, etc. is added.

Next, the automatic inspection equipment used in the above-mentioned automatic inspection steps 2 and 5 is shown in FIG. FIG. 2 shows an embodiment of an automatic inspection device in a processing apparatus according to the present invention, and a case where it is applied to a mask plate will be described. Note that the same applies to wafers, so the explanation will be omitted.

In the figure, 21 is a mask plate before or after resist application, 22 is foreign matter such as dust attached to the surface of the mask plate 210, 23 is a laser light source, and 24 is a mask plate that reflects the laser light from the laser light source 23. A high-speed scanning mirror 25 scans the laser beam irradiation area on the mask plate 21 at high speed, and 25 is a condenser lens that collects light scattered by the foreign matter 22 on the mask plate 21. When there is no foreign matter 22, the foreign matter 22 will not be caught by the condenser lens 25 because the foreign matter 22 will be emitted as a reflection light aperture for the incident light A as shown in the figure. 26 is a light detector that detects the light from the condensing lens 25; 27 is a conversion circuit that converts the presence or absence of a foreign object into digital signals "1" and "O" based on the detection signal from the light detector 26; 28 is this conversion circuit 27; A counting circuit 29 counts the output of this counting circuit 27 to a set value (1
Setting value for the number of foreign objects attached per sheet (for example, 10 pieces/sheet)
This is a determination circuit that determines a product to be defective if the number of attached foreign substances is equal to or greater than a set value, and determines it to be a good product if the number of attached foreign substances is smaller than the set value, and selects whether the product is good or defective.

Items that are determined to be good by this judgment circuit 29 are transported to the next process, but items that are determined to be defective are stored in a separate unloader from the non-defective items and returned to cleaning process 1 for re-cleaning. Become.

In addition, in an automatic inspection device using a laser beam, the condenser lens 25 needs to have a certain size so that it can detect scattered light from dust, etc.
It can be detected if it is more than enough information. Laser light source 23
In correspondence with the driving of the scanning device by laser beam irradiation made up of the scanning mirror 24 and the scanning mirror 24, the position of the photodetecting device made up of the condensing lens 25 and the photodetector 26 is also appropriately moved to perform beam scanning. However, instead of this beam scanning method, a method may be used in which the laser beam irradiation position is fixed and the mask plate 21 side is scanned using an XY table.

As described above, automatic inspection processes 2 and 5 are provided before and after the resist coating process 3, which often causes defects due to the adhesion of foreign substances, so that resists with a large amount of foreign substances such as dust, which can cause defects, are passed to the next process. Therefore, there are fewer defects in the final inspection step 12 of the resist processing step, and the appearance yield can be improved, and the yield of masks and wafers can be improved. Therefore, processing costs and material waste can be significantly reduced. Furthermore, automatic inspection using an automatic inspection device is much faster, more accurate, and more precise in selecting foreign matter than visual inspection. Therefore, even if an automatic inspection process 2 is added in addition to the automatic inspection process 5 which replaces the visual inspection process, the sorting process can be performed extremely quickly. Therefore, productivity can be improved.

[Effects] - 1. It is possible to supply coated parts (mask plates and wafers) or coated parts with no or little adhesion of foreign matter such as dust to the subsequent processing process, which reduces the occurrence of defects. The appearance yield can also be improved, and therefore the yield of coated members (masks and wafers) can be improved.

2. The biggest problem is the adhesion of foreign substances such as dust. The yield of coated parts (masks and wafers) is improved by installing automatic inspection equipment before and after the mask coating process to screen out items with a lot of foreign matter and prevent them from being transported to the next process. Therefore, processing costs and material waste can be reduced.

3. Compared to visual inspection, automatic inspection using automatic inspection equipment can screen out foreign matter much more quickly, accurately, and precisely. Therefore, in addition to providing the automatic inspection device after the coating process using the coating device, even if it is provided before the coating process, the automatic sorting process is extremely quick and productivity can be improved.

Although the invention made by the present inventor has been specifically explained based on examples above, the present invention is not limited to the above-mentioned examples, and it is understood that modifications can be made without departing from the gist of the invention. Needless to say. For example, although the above-mentioned embodiments refer to processing in the case of photoresist coating, the present invention is not limited thereto, and can be similarly applied to processing in the case of electron beam resist coating. Further, the automatic detection device is not limited to that shown in FIG. 2, and various modifications can be made without departing from the gist. Further, although automatic inspection steps 2 and 5 are used in the above embodiment, only one of them may be used as necessary.

[Application field]

In the above explanation, the invention made by the present inventor was mainly applied to the field of application in which the invention is based, which is the production of masks used in the manufacture of semiconductor integrated circuits and the resist processing apparatus during wafer processing. The invention is not limited thereto, and can also be applied, for example, to a processing apparatus that generally applies a coating material (for example, a photosensitive material such as a photoresist or an emulsion) to a member to be coated.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of a mask plate or wafer resist processing process to which the present invention is applied, and FIG. 2 is a simplified configuration diagram showing an example of an automatic inspection apparatus in the automatic inspection process of FIG. 1. It is. 1...Cleaning process, 2,5...Automatic inspection process, 3...
・Resist coating process, 4... Pre-pake process, 21.
. . . Mask plate, 22 . . . Foreign matter, 23 . . . Laser light source, 24 . . Scanning mirror, 25 .
... Counting circuit, 29... Judgment circuit. Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1. In a processing apparatus having a coating device for applying a coating material to a member to be coated, the coating material may be applied to the member to be coated or A processing device characterized by being equipped with an inspection device that automatically inspects whether foreign matter such as dust is attached to a member, selects whether it is good or bad, and prevents defective products from being conveyed to the next process. 2. The inspection device includes a device that scans an area where the member to be coated or the coated member is irradiated with a laser beam, and a device that detects light from foreign matter on the member to be coated or the coated member. a detector, a conversion circuit that converts the presence or absence of a foreign object into a digital signal based on the output of this optical detector, a counting circuit that counts the output of this conversion circuit, and a count output of this counting circuit that is compared with a set value. 2. The processing apparatus according to claim 1, further comprising a determination circuit that determines the quality of the member to be coated or the coated member and performs selection. 3. The processing apparatus according to claim 1 or 2, wherein a mask plate or a wafer is used as the member to be coated.