JP2000223403A - Coating-film forming method and coating system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating-film forming method and a coating system, which are capable of quickly correcting coating failures of various types and forming non-defective coating films. SOLUTION: Countermeasures which correct local coating failures that occur in the surface of a coating film are comprehended beforehand for each type of coating failures, and a coating film is formed on a substrate, and a coating failure occuring locally in the surface of the coating film is detected. A countermeasure is taken against a detected coating failure corresponding to its type as being selected from among the previously comprehended countermeasures, and then the coating film is formed on a substrate under conditions where the corresponding countermeasures are taken.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a coating film forming method and a coating processing system for forming a coating film such as a resist film on a surface of a substrate such as a semiconductor wafer or a liquid crystal display (LCD) substrate.

[0002]

2. Description of the Related Art For example, in a photolithography step in a semiconductor device manufacturing process, a resist coating process for forming a resist film on the surface of a semiconductor wafer and an exposure process of a predetermined pattern on the semiconductor wafer after the resist coating are performed. After that, a development process for developing the pattern is performed. In this resist coating process, a spin coating method or the like is frequently used as a method for uniformly applying a resist liquid on the surface of a semiconductor wafer.

FIG. 13 shows an outline of a conventional coating unit using the spin coating method. For example, in a state where the semiconductor wafer W is fixedly held by the vacuum chuck by the spin chuck 141, the semiconductor wafer W is rotated together with the spin chuck 141 by a rotating unit (not shown), and the resist nozzle 142 arranged above the semiconductor wafer W causes the wafer W surface to move. A resist solution is dropped at the center of the substrate. The dropped resist liquid is spread radially outward of the wafer W by centrifugal force. Thereafter, the dropping of the resist solution is stopped, and the semiconductor wafer is rotated at a predetermined speed to shake off and dry the remaining resist. As a result, a resist film having a predetermined thickness is formed on the semiconductor wafer.

[0004]

When a resist solution is applied to a wafer, it is necessary to apply the resist solution uniformly and evenly. However, the resist solution which is not locally applied is used. An application defect (application unevenness) such as a locally applied thin or thick application may occur.

[0005] Such defective coating occurs on the wafer during or after the application of the resist liquid. The distribution of the defective liquid is that the resist liquid is locally or thinly applied to the center or the vicinity of the wafer. There are various cases, such as a case where a resist solution is locally thinly or thickly applied to an intermediate portion between the center and the outer edge of the wafer.

[0006] Such various local coating defects are caused by various causes. To solve these problems, conventionally, based on the experience of each technician, individual coating means have been taken by trial and error. And there is no systematic method for preventing coating defects that appear in various forms.

Therefore, when a local coating defect occurs in the coating film, it takes time to find out the cause and eliminate the coating defect, thereby deteriorating productivity.

The present invention has been made in view of the above circumstances, and provides a coating film forming method and a coating processing system capable of quickly eliminating coating defects appearing in various forms and forming a sound coating film. The purpose is to provide.

[0009]

According to a first aspect of the present invention, there is provided a countermeasure for solving a local coating defect occurring on the surface of a coating film formed on a substrate. A process of grasping in advance for each type of coating failure,
A step of forming a coating film on a substrate, a step of detecting a coating defect locally occurring in the coating film, and a countermeasure for eliminating the local coating defect occurring in the previously grasped coating film surface. A method for forming a coating film on a substrate under the conditions after the countermeasure, based on the following: You.

According to a second aspect of the present invention, a step of forming a coating film by supplying a coating liquid from a nozzle onto a substrate and a coating defect locally occurring in the coating film formed on the substrate are eliminated. Depending on the process of detecting and the form of the coating failure that occurred,
(I) adjustment of the centering state of the application liquid discharge nozzle,
(Ii) adjustment of an opening / closing valve or suck-back valve interposed in a coating liquid supply pipe connected to the coating liquid discharge nozzle, (iii) execution of dummy dispensing of the coating liquid discharge nozzle, and (iv) rotation of the substrate. And (v) increasing the discharge amount of the coating liquid, and forming a coating film on the substrate under the conditions after performing any of the above-mentioned measures. And a method of forming a coating film.

According to a third aspect of the present invention, a coating processing unit for discharging a coating liquid from a coating liquid supply nozzle to a substrate while rotating the substrate to form a coating film on the substrate, and a coating unit formed on the substrate. Detecting means for detecting a local coating defect occurring in the coated film, and i) adjusting the centering state of the coating liquid discharge nozzle according to the form of the coating defect detected by the detecting means. ii) adjustment of an opening / closing valve or suck-back valve interposed in a coating liquid supply pipe connected to the coating liquid discharge nozzle, iii) execution of dummy dispensing of the coating liquid discharge nozzle, and iv) rotation conditions for rotating the substrate. And v) increasing the discharge amount of the coating liquid.

In the present invention, the present inventors analyze the causes of coating defects, and grasp in advance measures for eliminating coating defects corresponding to each cause for each type of coating defects. Based on the measures taken for each coating defect that has been grasped in advance, a countermeasure is taken in accordance with the type of coating defect detected, and a coating film is formed on the subsequent substrate under the conditions after the countermeasure. Can be quickly eliminated, and a sound coating film free from local coating defects can be formed without deteriorating productivity.

In the present invention, (i) adjusting the centering state of the coating liquid discharge nozzle, and (ii) adjusting the coating liquid connected to the coating liquid discharge nozzle in accordance with the detected form of the local coating defect. Adjustment of an opening / closing valve or suck-back valve interposed in the supply pipe, (iii) dummy dispensing of a coating liquid discharge nozzle, (iv) adjustment of rotation conditions for rotating a substrate, and (v) coating liquid Since any one of the measures against the increase in the discharge amount is performed, an optimal means for eliminating the coating failure can be promptly taken according to the form of the coating failure. Therefore, the coating failure can be quickly eliminated without the engineer performing trial and error, and a sound coating film free of local coating failure can be formed without deteriorating the productivity.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIGS. 1 to 3 are views showing the overall configuration of a coating and developing system 1 for a semiconductor wafer (hereinafter, referred to as “wafer”) to which an embodiment of the present invention is applied. FIG. 1 is a plan view and FIG. 3 shows the front, and FIG. 3 shows the back.

As shown in FIG. 1, the coating and developing system 1 loads a plurality of wafers W as substrates to be processed into a system, for example, 25 wafers in a wafer cassette CR, or unloads the wafers from the system. A cassette station 10 for loading and unloading wafers W into and out of the wafer cassette CR, and various single-wafer processing units for performing predetermined processing on the wafers W one by one in a coating and developing process. A configuration in which a processing station 11 arranged in multiple stages and an interface unit 12 for transferring a wafer W between an exposure apparatus (not shown) provided adjacent to the processing station 11 are integrally connected. have.

In the cassette station 10, FIG.
As shown in FIG.
At a position 0a, a plurality of wafer cassettes CR, for example, up to four wafer cassettes CR are placed in a line in the X direction with their respective wafer entrances facing the processing station 11 side. A wafer carrier 21 that can move in the wafer arrangement direction (Z direction: vertical direction) of the wafers stored in the cassette selectively accesses each wafer cassette CR.

Furthermore the wafer transfer member 21 is configured to be rotatable in θ direction, alignment belonging to the third multi-stage unit of the processing unit group G ₃ of the processing station 11 side as described later unit (ALIM) And an extension unit (EXT).

As shown in FIG. 1, the processing station 11 is provided with a vertical transfer type main wafer transfer mechanism 22 equipped with a wafer transfer device, and all the processing units are surrounded by one or more sets. Are arranged in multiple stages.

As shown in FIG. 3, the main wafer transfer mechanism 22 is provided with a wafer transfer device 46 inside a cylindrical support 49 so as to be able to move up and down in the vertical direction (Z direction). The cylindrical support 49 is connected to a rotation shaft of a motor (not shown), and is rotated integrally with the wafer transfer device 46 about the rotation shaft by the rotation driving force of the motor, whereby the wafer transfer is performed. The device 46 is rotatable in the θ direction. Note that the cylindrical support 49 may be configured to be connected to another rotating shaft (not shown) rotated by the motor.

The wafer transfer device 46 includes a plurality of holding members 48 that are movable in the front-rear direction of the transfer base 47, and the transfer of the wafer W between the processing units is realized by these holding members 48. .

Also, as shown in FIG.
Processing unit group G₁, G₂, G ₃, G₄, G₅Is arranged
First and second processing unit groups
G₁, G₂The multi-stage unit is located at the front of the system (Fig. 1).
And the third processing unit group G₃of
The multi-stage unit is arranged adjacent to the cassette station 10.
And a fourth processing unit group G₄Multi-stage unit
Fifth processing, which is disposed adjacent to the
Unit group G₅Multi-stage unit is located on the rear side.
And it is possible.

As shown in FIG. 2, the first processing unit group G _1, 2 spinner-type processing units of the wafer W is mounted on a spin chuck performs predetermined processing in a cup CP, for example, a resist coating unit (COT) and the developing unit (DEV) are stacked in two stages from the bottom. Second processing even unit group G _2, two spinner-type processing units, for example, a resist coating unit (C
OT) and the developing unit (DEV) are stacked in two stages from the bottom. The resist coating unit (COT) is preferably disposed at the lower stage because drainage of the resist solution is troublesome both mechanically and for maintenance. However, it is of course possible to appropriately arrange the upper stage as needed.

As shown in FIG. 3, the third processing unit group G _3, oven-type processing units of the wafer W is placed on a mounting table SP performs predetermined processing, for example, a cooling unit (COL) , An adhesion unit (AD) for performing a so-called hydrophobizing process for improving the fixability of a resist, an alignment unit (ALIM) for positioning, and an extension unit (EX)
T), a pre-baking unit (PREBAKE) for performing a heating process before the exposure process and a post-baking unit (POBAKE) for performing a heating process after the exposure process are stacked in, for example, eight stages from the bottom.

[0024] Even the fourth processing unit group _{G 4,} oven-type processing units, for example, a cooling unit (CO
L), extension cooling unit (EXT
COL), an extension unit (EXT), a cooling unit (COL), a pre-baking unit (PREBAKE), and a post-baking unit (POBAKE) are stacked in order from the bottom, for example, in eight stages.

As described above, the cooling unit (COL) and the extension cooling unit (EXTCOL) having a low processing temperature are arranged in the lower stage, and the baking unit (PREBAKE), the post-baking unit (POBAKE) and the adhesion having a high processing temperature are arranged. By arranging the units (AD) in the upper stage, thermal mutual interference between the units can be reduced. Of course, a random multi-stage arrangement may be used.

As shown in FIG. 1, the interface section 12 has the same dimensions as the processing station 11 in the depth direction (X direction), but is set smaller in the width direction. A portable pickup cassette CR and a stationary buffer cassette BR are provided in front of the interface section 12.
On the other hand, a peripheral exposing device 23 is arranged on the back side, and a wafer carrier 24 is provided on the central part. The wafer carrier 24 moves in the X and Z directions to move the cassettes CR and BR and the peripheral exposure device 2.
3 is accessed. The wafer transfer body 24 is configured so as also to be rotatable in the θ direction, wherein the processing station 11 side of the fourth processing unit extension units belonging to the multi-stage units of group G ₄ (EXT) and, further Can also access a wafer transfer table (not shown) on the adjacent exposure apparatus side.

In the coating and developing system 1, as shown in FIG. 1, a multi-stage unit of the _fifth processing unit group G5 indicated by a broken line is also arranged on the back side of the main wafer transfer mechanism 22 as described above. Although the multi-stage unit of the _fifth processing unit group G5 has the guide rail 25
, And can be shifted to the side as viewed from the main wafer transfer mechanism 22. Therefore, even when provided as a multi-stage unit of the fifth processing unit group G ₅ shown, by sliding along the guide rail 25, the space portion can be secured, to the main wafer transfer mechanism 22 The maintenance work can be easily performed from behind. Note that the multi-stage unit of the _fifth processing unit group G5 is not limited to such a linear slide shift along the guide rail 25, but may be a system as shown by a one-dot chain line reciprocating rotation arrow in FIG. Even if it is configured to rotate outward, it is easy to secure a space for maintenance work on the main wafer transfer mechanism 22.

[0028] In such a resist coating and developing system, in the cassette station 10, one wafer W from the wafer cassette CR by the wafer transfer body 21 is taken out, the extension unit of the processing unit group G ₃ (EXT) Conveyed. Then, the wafer W is first processed by the wafer transfer device 46 of the main wafer transfer mechanism 22 in an adhesion processing unit (AD) so as to make the wafer W hydrophobic (HM) to enhance the fixability of the resist.
DS processing). Since this process involves heating, the wafer W is then transferred to a cooling unit (COL) by the wafer transfer device 46 and cooled. Subsequently, the wafer W is transferred by the wafer transfer device 46 to a resist coating unit (COT), and a coating film is formed as described later.

After the completion of the coating process, the wafer W is pre-baked in a pre-baking unit (PREBAKE), and then cooled in a cooling unit (COL). The cooled wafer W is supplied to the alignment unit (A
Is conveyed to LIM), where it is aligned, extension unit of the processing unit group _{G 4} (EX
T).

Thereafter, the wafer W is transferred to the interface section 12 by the wafer transfer body 24, and the peripheral exposure device 2
After the peripheral resist is exposed by 3 to remove an excess resist, the resist is exposed to a predetermined pattern by an exposure device (not shown) provided adjacent to the interface section 12.

The exposed wafer W is returned to the interface section 12 again, and is carried by the wafer carrier 24 to the extension unit (EXT). Then, the wafer W is transferred to any one of the post-baking units (POBAKE) by the wafer transfer device 46 and subjected to post-exposure bake processing, and then cooled by the cooling unit (COL).

Thereafter, the wafer W is transferred to the developing unit (DE).
V), where the exposure pattern is developed. After the development is completed, the wafer W is transferred to any one of the post-baking units (POBAKE) and subjected to post-baking, and then cooled by the cooling unit (COL). After such a series of processing is ended, the returned to the cassette station 10 via extension unit of the processing unit group G ₃ a (EXT), it is inserted into one of the cassettes CR.

In these processes, a plurality of wafers W are successively supplied to the processing station 11 and are continuously performed.

Next, the resist coating unit (COT) in this embodiment will be described. 4 and 5 are a schematic cross-sectional view and a schematic plan view showing the entire configuration of the resist coating unit (COT).

This resist coating unit (COT)
An annular cup CP is arranged at the center of the
The spin chuck 52 is arranged inside the. The spin chuck 52 is rotationally driven by a drive motor 54 in a state where the wafer W is fixedly held by vacuum suction. The drive motor 54 is connected to the opening 5 provided in the unit bottom plate 50.
0a, and is coupled to a lifting drive means 60 and a lifting guide means 62, for example, an air cylinder, via a cap-like flange member 58 made of, for example, aluminum. A cylindrical cooling jacket 64 made of, for example, SUS is provided on a side surface of the drive motor 54.
The flange member 58 is attached so as to cover the upper half of the cooling jacket 64.

At the time of resist application, the lower end 58a of the flange member 58 is in close contact with the unit bottom plate 50 near the outer periphery of the opening 50a, thereby sealing the inside of the unit. Spin chuck 52 and holding member 48 of main wafer transfer mechanism 22
When the transfer of the wafer W is performed, the lower end of the flange member 58 floats from the unit bottom plate 50 by the lifting drive means 60 lifting the drive motor 54 or the spin chuck 52 upward.

A resist nozzle 86 for discharging a resist solution onto the surface of the wafer W is connected through a resist supply pipe 88 to an air operation valve 130 (FIG. 6) described later. The resist nozzle 86 is detachably attached to the tip of a resist nozzle scan arm 92 via a nozzle holder 100. The resist nozzle scan arm 92 is connected to the unit bottom plate 50.
Guide rail 94 laid in one direction (Y direction)
It is attached to the upper end of a vertical support member 96 that can move horizontally above, and moves in the Y direction integrally with the vertical support member 96 by a Y-direction drive mechanism (not shown).

The resist nozzle scan arm 92
Can also be moved in the X direction perpendicular to the Y direction in order to selectively attach the resist nozzle 86 in the resist nozzle standby section 90, and is also moved in the X direction by an X direction driving mechanism (not shown). .

Further, in the resist nozzle standby section 90, the discharge port of the resist nozzle 86 is inserted into the port 90a of the solvent atmosphere chamber and exposed to the solvent atmosphere so that the resist liquid at the nozzle tip does not solidify or deteriorate. It has become. Further, a plurality of resist nozzles 86 are provided, and these nozzles can be selectively used depending on, for example, the type of the resist liquid.

The resist nozzle scan arm 92
A thinner nozzle 101 for discharging a solvent for wetting the wafer surface, for example, a thinner, on the wafer surface prior to the discharge of the resist liquid onto the wafer surface is attached to the tip (nozzle holder 100) of the wafer. The thinner nozzle 101 is connected to a thinner supply unit via a solvent supply pipe (not shown). The thinner nozzle 101 and the resist nozzle 86 are mounted such that each discharge port is located on a straight line along the Y movement direction of the resist nozzle scan arm 92.

Further, on the guide rail 94, a vertical support member 8 for supporting the resist nozzle scan arm 92 is provided.
6, a vertical support member 122 that supports the rinse nozzle scan arm 120 and is movable in the Y direction is also provided. A rinsing nozzle 124 for side rinsing is attached to the tip of the rinsing nozzle scan arm 120. A rinsing nozzle scan arm 120 and a rinsing nozzle 12 are driven by a Y-direction driving mechanism (not shown).
Reference numeral 4 denotes a rinsing nozzle standby position (solid line position) set on the side of the cup CP and a rinsing liquid discharge position (dotted line position) set immediately above the periphery of the wafer W installed on the spin chuck 52. It translates or moves linearly between and.

Next, a supply system of the resist solution will be described with reference to FIG. FIG. 6A is a schematic view of an air operation valve and a suck-back valve interposed in a resist supply pipe, and FIG. 6B is a cross-sectional view of the suck-back valve.

As shown in FIG. 6A, an air operation valve 130 (open / close valve) and a suck-back valve 131 are integrally provided in the resist supply pipe 88. The air operation valve 130 is
A valve (not shown) is opened and closed by the air supplied from the air supply pipe 132 to switch between flowing out and stopping the resist solution in the resist supply pipe 88. Further, by adjusting a speed controller 130a provided in the air operation valve 130, the opening / closing speed of a valve body (not shown) can be adjusted.

As shown in FIG. 6B, the suck back valve 131 is provided with a housing 134 to which an air supply pipe 133 is connected. In the housing 134, a valve body 135 is slidably provided. It is interposed. The valve element 135 is urged by a spring 136 in a direction in which the resist liquid in the resist supply pipe 88 is drawn (to the right in FIG. 6B).

A switching valve (not shown) provided in the air supply pipe 133 switches between supplying hair into the housing 134 and discharging air from the housing 134.

Therefore, when the air supplied into the housing 134 is discharged, the valve element 135 is moved rightward by the urging force of the spring 136, and the resist supply pipe 8 is moved.
8 is drawn into the housing 134, and a predetermined amount of the resist solution is sucked back. on the other hand,
When air is supplied from the air supply pipe 133 into the housing 134, the valve element 135 causes the spring 136 to be supplied by the air.
Is pressed to the left against the urging force, and the sucked-back resist solution is returned to the resist supply pipe 88.

The amount of suck-back of the resist solution is defined by the amount of movement of the valve element 135, and the amount of suck-back can be adjusted by adjusting the amount of movement of the valve element 135. In addition, the suck back speed is determined by the air supply pipe 1
It is possible to adjust the moving speed of the valve body 135 by adjusting the air discharge speed of the switching valve 33 (not shown). Specifically, the suck back valve 13
The speed controller 131a provided in FIG.
By adjusting (a), the suck-back speed can be adjusted.

FIG. 7 shows a resist coating unit (CO
It is a figure which shows the structure of the control system of T). The controller 137 of the coating processing unit controls each unit in the resist coating processing unit (COT), and includes, for example, a drive motor 54 for rotating the wafer W, and an air operation valve for switching between supply and stop of the resist solution. 130, a suck-back valve 131 for sucking back the resist solution, and a thinner supply unit 138 for supplying a thinner are controlled.

The operation of the resist coating apparatus unit (COT) configured as described above in which a resist solution is applied by a resist-saving method in which the consumption of the resist liquid is smaller than in the conventional method will be described below.

The cup C in the resist coating unit (COT) is held by the holding member 48 of the main wafer transfer mechanism 22.
When the wafer W is transported right above P, the wafer W
Is sucked in vacuum by the spin chuck 52 which has been lifted by the lift drive means 60 and lift guide means 62, for example, which are air cylinders. Main wafer transfer mechanism 2
After the wafer W is vacuum-sucked on the spin chuck 52, the holding member 48 is moved to the resist coating unit (CO).
T) Pull back from inside, resist coating unit (CO
The delivery of the wafer W to T) is completed.

Then, the spin chuck 52 lowers the wafer W to a fixed position in the cup CP, and the driving motor 54 starts rotating the spin chuck 52. After that, the nozzle holder 10 from the resist nozzle standby unit 90
The movement of 0 is started. The movement of the nozzle holder 100 is performed along the Y direction.

As shown in FIG. 8A, when the discharge port of the thinner nozzle 101 reaches the center of the spin chuck 52 (the center of the wafer W), the thinner is supplied to the surface of the rotating wafer W. The thinner supplied to the surface of the wafer W is uniformly spread from the center of the wafer W to the entire area around the thinner by centrifugal force. As described above, by performing a so-called pre-wet treatment in which the entire surface of the semiconductor wafer W is wetted with a solvent such as a thinner prior to the application of the resist solution, the resist is more easily diffused, and as a result, a smaller amount of the resist solution is used. It is possible to form a uniform resist film by the amount.

Subsequently, the nozzle holder 100 is moved to the position shown in FIG.
As shown in (b), the resist nozzle 86 is moved in the Y direction until it reaches the center of the wafer W. In the case where the resist discharge amount is reduced from the viewpoint of reducing the resist consumption, the wafer W is rotated at a high speed when the resist liquid is discharged. For example, the resist discharge amount is 1 to 1.5 m
l, it is set to about 3000 rpm,
When the amount is as small as about 0.5 ml, 5000 rpm
m. In this state, the resist liquid is dropped from the discharge port of the resist nozzle 86 to the center of the surface of the rotating wafer W, and is diffused from the center of the wafer W to the periphery by centrifugal force, so that the resist film is formed on the wafer W. It is formed.

At the start of the discharge of the resist solution from the resist nozzle 86, as shown in FIG. 9A, the speed controller 1 of the air operation valve 130 is controlled so as not to trap air bubbles from the tip portion 86a of the nozzle.
Adjust 30a.

At the end of the discharge of the resist solution, as shown in FIG.
By adjusting the opening / closing speed of a valve body (not shown) by adjusting the speed controller 130a of 0, the height of the liquid surface of the resist solution is set to, for example, 0.5 to 1 from the nozzle tip.
Pull up to a height of mm.

Thus, the resist liquid existing at the tip of the nozzle 86 at the end of the discharge of the resist is prevented from being drawn into the nozzle 86 and dropped onto the wafer W. Therefore, it is possible to effectively prevent the coating unevenness of the resist solution and the unevenness of the film thickness. In particular, when the substrate is rotated at a high speed from the viewpoint of reducing the amount of the resist liquid as in the present embodiment, if the resist liquid is dropped on the wafer W after the discharge of the resist liquid, the coating unevenness of the resist liquid and the film thickness may be reduced. Non-uniformity is likely to occur, but since the dripping of the resist liquid is prevented in this way, even when the substrate is rotated at a high speed, it is possible to effectively prevent the coating unevenness and the non-uniform film thickness of the resist liquid. Can be.

Next, as shown in FIG. 9C, the suck-back amount of the suck-back valve 131 is adjusted for a predetermined time, for example, 2 seconds from the end of the discharge of the resist liquid, so that the liquid level of the resist liquid is adjusted. The height is further raised so as to be at a height of, for example, 2 to 3 mm from the tip of the nozzle 86.

By raising the resist liquid level in the second step, the resist nozzle 86 can be moved when the resist nozzle 86 moves.
The resist liquid is prevented from drying, and is prevented from dropping carelessly. Therefore, generation of particles due to the resist liquid can be effectively prevented.

After the completion of the dropping of the resist solution, the wafer W is rotated at a predetermined rotation speed to adjust the film thickness. Next, the rotation speed of the wafer W is accelerated, and the remaining resist liquid is shaken off and dried to form a resist film having a predetermined thickness. By reducing the rotation speed of the wafer W for a predetermined time during the film thickness adjustment, the discharged resist liquid can remain on the outer peripheral portion of the wafer W as much as the central portion. Even in the case of the resist-saving method in which the amount of the resist solution dropped is small, the resist film thickness can be made uniform.

Thereafter, the nozzle holder 100 is returned to the home position, and the wafer W is
Is back-rinsed, and if necessary, side edges of the wafer W are side-rinsed by cleaning means (not shown). Thereafter, the rotation speed of the wafer W is accelerated,
The rinsing liquid of the back rinsing and the side rinsing is shaken off and discarded, and thereafter, the rotation of the wafer W is stopped, and the coating process ends.

As described above, the resist nozzle 86 is moved 2 to 3 mm from the nozzle tip by the suck back valve 131.
Is held in a state in which the resist liquid surface is pulled up to the height of the wafer W, and when the resist liquid is discharged to the subsequent wafer W, the wafer W is moved to the center of the wafer W again. At the time of the next discharge of the resist liquid, by injecting the resist liquid as it is without changing the surface of the resist liquid, careless dropping of the resist liquid at the time of movement can be prevented. Further, the liquid level of the resist liquid may be lowered to, for example, about 0.5 to 1 mm from the nozzle tip before the resist liquid is discharged onto the subsequent wafer W. Accordingly, it is possible to prevent an error in the amount of the resist solution accompanying the raising of the resist solution level of the suck back valve 131.

As described above, the coating unevenness of the resist solution and the unevenness of the film thickness are prevented, but local coating unevenness may occur due to various causes. In the present embodiment, local application unevenness that occurs in various forms is eliminated by the following measures.

That is, first, the coating unevenness at the time of forming the resist film was determined by using No. 1 in FIG. The method is classified into the five forms shown in 1 to 5, the cause of application unevenness is analyzed for each form, and a measure for solving the application unevenness corresponding to each cause is grasped in advance to obtain a list as shown in FIG. create.

As a process of detecting the pattern of the coating unevenness, it is conceivable to check the coating unevenness on the wafer W at the same time as checking the thickness of the resist film once a day in the coating and developing process. Can be Further, when the yield of the wafer W after the application and the development is reduced, it is conceivable to check the state of the application unevenness as a part of investigating the cause. In order to grasp the coating unevenness in this way, for example, outside the resist coating and developing system, it can be performed, for example, visually or by a film thickness measuring device using laser light or the like.

If a film thickness measuring device using a laser beam or the like or a CCD camera or the like is provided as a detecting means in the resist coating and developing system, for example, the resist coating is completed, and the exposure processing is performed by a prebaking unit (PREBAKE). After performing the previous heating process and performing the cooling process by the cooling unit (CDL), the coating unevenness of the wafer W can be grasped inline. Such detection means, for example, as shown in FIG. 11, be provided on the detection unit 110 provided in place of one of the cooling unit of the processing unit group G ₄ (COL), the coating unevenness detected by the detection means Depending on the mode, the controller 137 may adjust a predetermined portion so as to eliminate coating unevenness. FIG.
As shown in FIG.
May be displayed on the display device 140 on the basis of the above signal.

Next, the form of the coating unevenness, its cause and countermeasures will be individually described. No. in FIG. 1 is a coating unevenness form in which the resist liquid is locally or thinly applied to the center or the vicinity of the wafer W. The first cause of this mode is presumed to be that the resist nozzle 86 is decentered, and the second cause is that the air operation valve 130 or the suck back valve 131 is insufficiently adjusted to prevent the tip of the resist nozzle 86 from being shifted. It is presumed that the liquid residue of the resist liquid is generated in the first step. As a countermeasure against the first cause, the centering state of the resist nozzle 86 is adjusted so that the resist liquid spreads concentrically on the wafer W. Further, as a countermeasure against the second cause, the valve opening / closing speed of the air operation valve 130 or the suckback amount or suckback speed of the suckback valve 131 is adjusted again.

In FIG. Reference numeral 2 denotes a coating unevenness form in which the resist liquid is locally thinly or thickly applied to an intermediate portion between the center and the outer edge of the wafer W. The cause of this pattern is presumed to be insufficient adjustment of the air operation valve 130 or the suck-back valve 131. As a countermeasure against this cause, the opening / closing speed of the air operation valve 130 or the suckback amount or suckback speed of the suckback valve 131 is readjusted.

In FIG. Reference numeral 3 denotes a coating unevenness pattern in which the resist liquid is applied thinly or thickly in an elongated shape extending in the radial direction of the wafer W. The first cause of this pattern is presumed to be that the resist liquid remains at the tip of the resist nozzle 86 due to insufficient adjustment of the air operation valve 130 or the suck back valve 131. The second cause is presumed to be that bubbles or particles are mixed in the resist liquid supply system. Further, the third cause is presumed to be the presence of particles on the surface of the wafer W. As a countermeasure against the first cause, the valve opening / closing speed of the air operation valve 130 or the suckback amount or suckback speed of the suckback valve 131 is adjusted again. As a countermeasure against the second cause, a dummy dispensing of the resist nozzle 86 is performed to remove bubbles or particles from the resist supply system. As a countermeasure against the third cause, it is possible to check the evaluation wafer and replace the wafer W if necessary.

In FIG. Reference numeral 4 denotes a form in which the resist liquid is locally applied to the outer edge of the wafer W thinly or thickly. It is assumed that this is because the registration nozzle 86 is decentered. As a countermeasure against this cause, the centering state of the resist nozzle 86 is adjusted so that the resist liquid spreads concentrically on the wafer W. However, by adding a deceleration step of decelerating the rotation of the wafer W after the discharge of the resist liquid, it should basically be prevented from occurring. If coating unevenness appears even after adjusting the centering state, the number of rotations in the deceleration step is set to 500 rpm.
It is conceivable to reduce it to about m or less.

In FIG. Reference numeral 5 denotes a pattern in which a large number of local portions where the resist liquid is not applied are formed on the outer edge of the wafer W. The first of this pattern
Is presumed to be due to inappropriate rotation conditions of the wafer W, and the second is presumed to be due to the insufficient discharge amount of the resist liquid. As a countermeasure against the first cause, improvement of a rotation condition for rotating the wafer W can be cited. Specifically, the thinner shake-off time is shortened, or the number of rotations at the time of discharging the resist liquid is increased. As a countermeasure against the second cause, increasing the discharge amount of the resist liquid can be cited.

In this way, based on the list as shown in FIG. 10, a measure for eliminating the coating defect is taken in accordance with the detected form of the coating defect on the wafer W, and the condition after the countermeasure is taken. A resist coating process is performed on the next wafer W.

As described above, in this embodiment, the five forms of application unevenness, their causes, and countermeasures for their elimination are summarized in advance in a list as shown in FIG. Since appropriate measures are taken, it is possible to quickly take an optimal means for eliminating coating unevenness. Therefore, it is possible for the technician to quickly eliminate the uneven coating of the wafer W without trial and error, and to form a sound coating film free from local coating defects without deteriorating the productivity. it can.

Further, as described above, if the detecting means such as a camera is incorporated in the resist coating and developing system, the form of the coating unevenness can be grasped in-line, and the form of the coating unevenness can be grasped more quickly. A countermeasure can be taken, and the coating unevenness of the wafer W can be eliminated very quickly. In this case, as shown in FIG. 12, if the controller 137 causes the display device 140 to display a countermeasure corresponding to the form of the coating unevenness based on the signal of the detecting means 139, the coating unevenness can be more rapidly increased. Can be eliminated.

The present invention is not limited to the above embodiment, and various modifications are possible. For example, in the above embodiment, the coating apparatus for applying a resist liquid to a semiconductor wafer has been described. However, the present invention is also applied to a case where a resist liquid is applied to a substrate to be processed other than the semiconductor wafer, for example, an LCD substrate. be able to. Further, the coating film is not limited to the resist film, but may be another film.

[0075]

As described above, according to the present invention,
Measures for eliminating the coating failure are grasped in advance for each form of the coating failure, and based on these previously grasped measures for each coating failure, take measures according to the detected coating failure form,
Since a coating film is formed on the subsequent substrate under the condition after the countermeasure, coating defects appearing in various forms can be quickly eliminated, and there is no local coating defect without deteriorating productivity. It is possible to form a suitable coating film.

Further, according to the present invention, a predetermined countermeasure is taken in accordance with the form of the detected local coating defect, so that an optimal means for eliminating the coating defect can be promptly taken. . Therefore, the coating failure can be quickly eliminated without the engineer performing trial and error, and a sound coating film free of local coating failure can be formed without deteriorating the productivity.

[Brief description of the drawings]

FIG. 1 is a plan view showing the overall configuration of a semiconductor wafer coating and developing system according to an embodiment of the present invention.

FIG. 2 is a front view of the coating and developing system shown in FIG.

FIG. 3 is a rear view of the coating and developing system shown in FIG. 1;

FIG. 4 is a cross-sectional view showing the overall configuration of a resist coating unit mounted on the coating and developing system shown in FIG.

FIG. 5 is a plan view of the resist coating unit shown in FIG. 4;

FIG. 6 is a schematic diagram of an air operation valve and a suck-back valve interposed in a resist supply pipe, and a cross-sectional view of the suck-back valve.

FIG. 7 is a diagram showing a configuration of a control system of the resist coating unit shown in FIGS. 4 to 6;

FIG. 8 is a schematic diagram showing a state where a thinner is being discharged from a thinner supply nozzle and a state where a resist liquid is being discharged from a resist nozzle.

FIG. 9 is a schematic diagram showing the state of a resist nozzle during and after discharge of a resist solution.

FIG. 10 is a diagram showing a list of various types of application unevenness, causes of each occurrence, and countermeasures for eliminating the application unevenness.

FIG. 11 is a rear view showing a part of a resist coating and developing system including a detection unit provided with a film thickness measuring device or a CCD camera.

FIG. 12 is a diagram showing another configuration of the control system of the resist coating unit.

FIG. 13 is a schematic configuration diagram showing a conventional resist coating apparatus.

[Description of Signs] 52: Spin chuck (rotating means) 86: Resist nozzle (coating liquid discharge nozzle) 86a: Tip of nozzle 88: Resist supply pipe (coating liquid supply pipe) 130: Air operation valve (Open / close valve) 130a Speed controller 131 Suck back valve 131a Speed controller 137 Unit controller (control means) W Semiconductor wafer (substrate)

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H025 AB16 EA05 4D075 AC64 AC88 AC92 AC94 AC95 AC99 CA48 DA08 DB14 DC22 EA45 4F042 AA07 BA05 BA08 BA12 BA25 CB07 DD44 DE06 DH09 EB29 ED03 5F046 CD01 JA02 JA03 JA09 JA13 JA21 JA22

Claims (10)

[Claims] 1. A method of preliminarily grasping, for each type of coating defect, a measure for eliminating a local coating defect occurring on the surface of a coating film formed on a substrate, and forming a coating film on the substrate. And detecting a coating defect locally occurring on the coating film, and detecting the coating defect based on a measure for eliminating the local coating defect occurring on the coating film surface which is grasped in advance. A method for forming a coating film, comprising: a step of taking a measure according to a form of a defect; and a subsequent step of forming a coating film on a substrate under the condition after the measure. And (2) adjusting the centering state of a coating liquid discharge nozzle, and (ii) interposing a coating liquid supply pipe connected to the coating liquid discharge nozzle. (Iii) execution of dummy dispensing of the coating liquid discharge nozzle, (iv) adjustment of rotation conditions for rotating the substrate, and (v) increase of the discharge amount of the coating liquid, 2. The method according to claim 1, wherein one of the above measures is performed. 3. A step of forming a coating film by supplying a coating liquid from a nozzle onto the substrate; a step of detecting a coating defect locally occurring in the coating film formed on the substrate; (I) adjustment of the centering state of the application liquid discharge nozzle, (ii) adjustment of an opening / closing valve or suck-back valve interposed in the application liquid supply pipe connected to the application liquid discharge nozzle, (iii) A) performing dummy dispensing of the coating liquid discharge nozzle, (iv) adjusting rotation conditions for rotating the substrate, and (v) increasing the discharge amount of the coating liquid. Forming a subsequent coating film on the substrate under the condition after implementing any of the measures. 4. When the detected application failure is a mode in which the application liquid is locally applied thinly or thickly at or near the center of the substrate, (i) adjusting the centering state of the application liquid discharge nozzle; 4. The method according to claim 3, wherein (ii) adjusting an on-off valve or a suck-back valve interposed in a coating liquid supply pipe connected to the coating liquid discharge nozzle. 5. 5. In the case where the detected application defect is a mode in which the application liquid is locally applied thinly or thickly to an intermediate portion between the center and the outer edge of the substrate, (ii) the application liquid ejection nozzle The coating film forming method according to claim 3, wherein adjustment of an opening / closing valve or a suck-back valve interposed in the connected coating liquid supply pipe is performed. 6. A coating liquid connected to a coating liquid discharge nozzle when the detected coating defect is a thin or thick coating liquid applied in an elongated shape extending in the radial direction of the substrate. The coating film forming method according to claim 3, wherein adjustment of an opening / closing valve or a suck back valve provided in the supply pipe or (iii) dummy dispensing of a coating liquid discharge nozzle is performed. 7. In the case where the detected application failure is a mode in which the application liquid is locally applied to the outer edge of the substrate thinly or thickly, (i) the centering state of the application liquid discharge nozzle is adjusted. The method for forming a coating film according to claim 3, wherein: 8. When the detected coating defect has a form in which a number of local portions where the coating liquid is not applied are present at the outer edge of the substrate, (iv) a method for rotating the substrate. 4. The method according to claim 3, wherein the rotation condition is adjusted or (v) the discharge amount of the coating liquid is increased. 9. A coating processing unit for discharging a coating liquid from a coating liquid supply nozzle onto a substrate while rotating the substrate to form a coating film on the substrate, and a local processing unit generated on the coating film formed on the substrate. Detecting means for detecting a coating defect; and, depending on the form of the coating defect detected by the detecting means, i) adjusting the centering state of the coating liquid discharge nozzle; ii) being connected to the coating liquid discharge nozzle Adjustment of the open / close valve or suck back valve interposed in the coating liquid supply pipe, iii) execution of dummy dispensing of the coating liquid discharge nozzle, iv) adjustment of rotation conditions for rotating the substrate, and v) adjustment of the coating liquid. A coating processing system for performing any one of increasing a discharge amount. 10. According to the form of the local coating failure detected by the detection means, i) adjusting the centering state of the coating liquid discharge nozzle; ii) adjusting the coating liquid supply pipe connected to the coating liquid discharge nozzle. Adjustment of an interposed open / close valve or suck-back valve; iii) execution of dummy dispensing of a coating liquid discharge nozzle; iv) adjustment of rotation conditions for rotating the substrate; and v) increase of the coating liquid discharge amount. The coating processing system according to claim 9, further comprising a control unit that selects an optimal one of the measures.