JP2005311023A - Chemical treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein resist and metal, peeled off from wafers remain as a result of staying of chemical between the wafers in a horizontal chemical treatment tank and are stuck again to the front and rear surfaces of the wafer, when pulling a cassette holding the wafers from the chemical treatment tank. <P>SOLUTION: This apparatus uses the chemical treatment tank provided with a soaking-type chemical treatment tank, a holder for holding substrates in the chemical treatment tank, and a nozzle for jetting the chemical to the upper side and lower side of the substrates, in the neighborhood of the side surface of the holder in the chemical treatment apparatus. Thus, circulation of the chemical in the chemical treatment tank becomes uniform, and re-sticking to foreign matters is suppressed, such as peeled-off resist and metal, to the substrates is suppressed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a chemical processing apparatus and a chemical processing method using a lift-off method in a semiconductor device manufacturing method.

  In a semiconductor manufacturing apparatus having a conventional immersion chemical processing tank, as a method of holding an object to be processed (hereinafter referred to as a wafer) in the chemical processing tank, for example, the object to be processed is placed vertically or horizontally. There is something. What is placed vertically is characterized by chemical solution circulation in the chemical treatment tank. It has the feature that the foreign matter generated during the chemical cleaning process is removed by using the chemical overflow. For example, by arranging a tubular flat filter at the bottom of the current plate of the cleaning tank, In some areas, the chemical solution for cleaning obtains an ideal tank flow state from the bottom surface of the cleaning tank toward the upper water surface.

  On the other hand, many wafers that are horizontally placed are characterized by a transfer mechanism. For example, a lift-off processing apparatus having a wafer horizontal chemical processing tank described in Patent Document 1 moves a wafer batch-processed in a chemical processing tank to a spin chuck using a slider mechanism, a high-pressure chemical liquid, For example, it is a device that performs jet treatment with water or isopropyl alcohol. This method is characterized by using a slider to make the transition from batch processing to single wafer processing without the need for a complicated transport system such as a rotating system that rotates a wafer holding container (hereinafter referred to as a cassette). , Small footprint, high throughput, low cost. However, such a system in which the wafer is placed horizontally cannot employ an overflow as a chemical solution circulation mechanism in the chemical treatment tank, and therefore reattachment of foreign matters such as resist and metal that have been peeled off from the wafer is likely to occur.

  FIG. 6 is a schematic view showing an example of a lift-off device having a most commonly used horizontal wafer type chemical treatment tank that has been conventionally used. The lift-off device includes a resist stripping solution tank 201, an isopropyl alcohol immersion processing tank 202, a slider unit 203, and a single wafer jet processing unit 204. In this example, the resist stripping solution tank 201 is one tank and the isopropyl alcohol immersion treatment tank 202 is two tanks, but may be composed of one or two tanks. FIG. 7 shows details of the resist stripper 201 in FIG.

  The lift-off process by the lift-off device will be described next.

FIG. 8 is a sectional view of a wafer on which a resist and a metal are formed. A wafer obtained by patterning a resist 401 on a wafer 402 and depositing metal 403 and metal wiring 404 is first immersed in a resist stripping solution tank 301 filled with a resist stripping solution 307 shown in FIG. At this time, the wafer cassette holding stage 303 swings. In the resist stripping treatment tank 301, the stripping solution penetrates into the resist during the immersion, and due to the swelling action, the adhesiveness between the resist 401 and the wafer 402 and the adhesiveness between the resist 401 and the metal 403 shown in FIG. At this time, a part of the resist 401 and the metal 403 are peeled off from the wafer 402 and float in the tank. The resist stripping solution 307 is moved to the chemical solution circulation line 304 by the chemical solution circulation line pump 305 and supplied to the resist stripping treatment tank 301 in a clean state with the resist and metal removed when passing through the chemical solution circulation line filter 306. The The wafer is continuously replaced with the resist stripping solution in the isopropyl alcohol immersion treatment tank 202, moved to the single wafer jet processing unit 204 by the slider unit 203, and subjected to jet processing with high-pressure isopropyl alcohol, whereby the resist 401 and the metal 403 are completely removed from the wafer. The metal wiring 404 is formed by removing the metal wiring 404. Thereafter, spin drying is performed.
Japanese Patent Laid-Open No. 01-175236

  In a horizontal wafer type chemical processing tank, the processing chemical stays between the wafers, and at the same time, foreign substances such as resist and metal that have been peeled off from the wafer remain, and the wafer and the cassette that holds the wafer are processed with chemicals. There is a problem in that the foreign matter reattaches to the front and back surfaces of the wafer when it is lifted from the tank. During the lift-off process, the resist patterned on the wafer immersed in the resist stripping solution and the metal deposited on the resist are stripped from the wafer by the action of the resist stripping solution. At this time, the resist stripping solution between the wafers stays, and the resist, metal, etc. also stay in the resist stripping solution. Therefore, when the wafer is pulled up, the resist and metal that have stayed reattach to the wafer surface. In addition, metal and resist may adhere to the upper wafer back surface.

  The same applies to the isopropyl alcohol in the isopropyl alcohol immersion treatment tank 202 of FIG. Isopropyl alcohol serves to replace the resist stripper, but does not reduce the adhesion between the resist and the wafer. However, the resist and metal whose adhesion to the wafer is sufficiently lowered by the action of the resist stripping solution may be stripped into the isopropyl alcohol solution. This adheres to the front and back surfaces of the wafer.

  In order to solve the above-described problems, the chemical processing apparatus of the present invention has an ejection nozzle that ejects a processing chemical between wafers, and can generate a flow of the processing chemical without retaining the processing chemical between the wafers.

  The chemical processing apparatus of the present invention ejects a processing chemical solution between wafers by means of an ejection nozzle to improve the retention of the processing chemical solution, thereby flushing the resist and metal that have reacted with the resist stripping solution and stripped from the wafer into the chemical circulation line Move and remove with filter for chemical circulation line. As a result, foreign matter staying in the vicinity of the wafer is prevented from reattaching to the front and back surfaces of the wafer.

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

  FIG. 1 is a schematic view showing a lift-off device having a resist stripping solution tank provided with the ejection nozzle of the present invention. FIG. 2 is a diagram illustrating a lift-off process. As shown in FIG. 2A, a patterned resist 701 is formed on the wafer 702, and a metal 703 is deposited on the resist 701. The wafer 702 is immersed in the resist stripping solution tank 101 shown in FIG. At that time, the resist stripping solution 108 is supplied from the ejection nozzle 102 between the wafers 103 held horizontally in the cassette 104. Resist stripping solution 108 in the vicinity of the wafer that has deteriorated due to a chemical reaction with the resist is swept away by the action of the jet nozzle, and the resist stripping solution 108 that has not deteriorated is supplied to the wafer, causing further chemical reaction to cause adhesion between resist 701 and wafer 702. Reduce sex. Also, the resist and metal that have reacted with the resist stripping solution 108 and stripped from the wafer 103 are washed away, moved to the chemical solution circulation line 105, and removed by the chemical solution circulation line filter 106, thereby preventing the resist and metal from reattaching to the wafer. Figured.

  The wafer 103 processed in the resist stripping solution tank 101 is replaced with the resist stripping solution remaining on the wafer 103 in the isopropyl alcohol processing bath. Thereafter, the metal and the resist are completely removed by an isopropyl alcohol jet process. Then, as shown in FIG. 2B, metal wiring 704 is formed on the wafer 702.

  The number of resist and metal re-deposition on the wafer in this process was evaluated using a surface foreign matter inspection system, and it was 145.0 / wafer before mounting the ejection nozzle, but 17.7 / wafer after mounting the ejection nozzle. Met.

  As described above, it is possible to reduce re-deposition of resist and metal in the lift-off process.

  Note that a transfer cassette may be used to hold the wafer when the lift-off process is performed by a lift-off device having a resist stripping solution tank. By using the transfer cassette, one or a plurality of wafers can be processed at the same time, so that throughput can be improved.

  In the ejection nozzle 102 shown in FIG. 1, the pitch of the ejection ports 903 provided in the nozzle 901 that discharges the resist stripping solution may be the same as the pitch of the wafer 902 as shown in FIG. As a result, a resist stripping solution is supplied between all wafers and a flow is generated, so that the residue of foreign matter such as resist and metal stripped is suppressed, and variations in workmanship between wafers in the tank are suppressed. be able to.

  In the jet nozzle 102 shown in FIG. 1, the diameter of the jet outlet 904 for discharging the resist stripping solution may be small at the upper part of the nozzle 901 and larger at the lower part of the nozzle 901 as shown in FIG. As a result, the flow of the processing chemical between the upper and lower wafers in the chemical processing tank is made uniform, and the resist stripping solution is uniformly supplied to all the wafers, and the remaining foreign matters such as resist and metal are removed. Is suppressed, and variations in workmanship between wafers in the tank can be suppressed.

  In addition, in the ejection nozzle 102 shown in FIG. 1, the number of nozzles is one in FIG. 1, but two or more may be sufficient. Thereby, the circulation of the chemical solution in the chemical solution treatment tank becomes uniform, and reattachment of foreign matters such as resist and metal peeled off can be suppressed.

  In addition, in the ejection nozzle 102 shown in FIG. 1, you may use the nozzle 801 which branches in the middle as shown in FIG. Thereby, the circulation of the chemical solution in the chemical solution treatment tank becomes uniform, and reattachment of foreign matters such as resist and metal peeled off can be suppressed.

  The chemical processing apparatus having the ejection nozzle of the present invention can suppress the reattachment of resist and metal and the adhesion of foreign matters in the lift-off process and resist stripping process, and is useful as a chemical processing apparatus used in semiconductor manufacturing.

Diagram showing resist stripping tank Diagram showing the process flow of lift-off processing Diagram showing the relationship between nozzle and wafer position The figure which shows arrangement of the spout provided in the nozzle Diagram showing nozzle branched into two A diagram showing a conventional lift-off peeling apparatus The figure which shows the conventional lift-off device Figure showing a cross section of a wafer

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Resist stripping tank 102 Ejection nozzle 103 Wafer 104 Cassette 105 Chemical solution circulation line 106 Chemical solution circulation line filter 108 Resist stripping solution 201 Resist stripping processing tank 202 Isopropyl alcohol immersion processing tank 203 Slider part 204 Single wafer jet processing part 301 Resist stripping process Tank 302 Wafer 303 Wafer cassette holding stage 304 Chemical liquid circulation line 305 Chemical liquid circulation line pump 306 Chemical liquid circulation line filter 307 Resist stripping solution 401 Resist 402 Wafer 403 Metal 404 Metal wiring 701 Resist 702 Wafer 703 Metal 704 Metal wiring 801 Nozzle 901 Nozzle 902 Wafer 903 Spout 904 Spout

Claims (5)

Immersion type chemical treatment tank,
A holding unit for horizontally holding the substrate in the chemical treatment tank;
A chemical processing apparatus, comprising: a nozzle that ejects a chemical solution upward and downward of the substrate near a side surface of the holding unit in the chemical solution treatment tank. The holding unit holds a plurality of the substrates,
The chemical processing apparatus according to claim 1, wherein the nozzle has an ejection port for ejecting a chemical between the held substrates. The chemical solution processing apparatus according to claim 2, wherein the jet outlet at the upper part of the nozzle is smaller than the jet outlet at the lower part of the nozzle. The chemical treatment apparatus according to claim 1, wherein the nozzle is branched. Holding the substrate horizontally in the chemical solution in the chemical treatment tank;
And a step of ejecting the chemical solution from the side surface of the substrate to circulate the chemical solution in the chemical treatment tank.

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