JPH05190436A - Resist coating apparatus - Google Patents

Abstract

PURPOSE:To perform a stable and uniform resist coating operation by a method wherein, even when a dummy dispensing operation is executed, an object to be treated is maintained in a prescribed temperature state. CONSTITUTION:A semiconductor wafer 18 is subjected to an HMDS treatment in an HMDS treatment mechanism 26; after that, it is cooled, inside a cooling mechanism 30, down to a set temperature which is suitable for a resist coating operation; then, it is carried out from the cooling mechanism 30; it is passed through a wafer conveyance chamber 32; and it is carried into a resist coating mechanism 24. When conditions for executing a dummy dispensing operation are established, a main control part gives to a resist control part an instruction which indicates that the execution of the dummy dispensing operation is completed before the semiconductor wafer 18 is carried into the resist coating mechanism 24. Thereby, immediately after the semiconductor wafer 18 has been carried into the resist coating mechanism 24, the resist coating operation is executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resist coating apparatus.

[0002]

2. Description of the Related Art For example, in a semiconductor device manufacturing apparatus for coating a resist on a semiconductor wafer, the wafer is mounted and fixed on a spin chuck arranged inside a processing chamber, and the wafer is rotated above the wafer. Drop a predetermined amount of resist liquid from the resist nozzle onto the wafer surface,
The resist solution is diffused by centrifugal force to form a photoresist film.

In such a resist coating apparatus,
If the resist coating operation is interrupted for a long time due to a lot break or the like, the resist liquid that comes into contact with air at the tip of the resist nozzle will solidify or deteriorate, and the discharge amount will change or solidify or deteriorate in the next coating process. If the resist solution is dropped, proper resist coating may not be possible. Therefore, when the resist solution is not dripped from the resist nozzle for a set time or more, the resist solution is discharged and discarded at a predetermined place, for example, the nozzle standby position. This resist discarding work is called dummy dispensing. ing.

By the way, in this type of resist coating apparatus, in order to enhance the adhesion between the resist and the wafer surface,
Prior to the resist coating step, a treatment for making the surface of the semiconductor wafer hydrophobic (HMDS treatment) may be performed using hexamethyldisilazane (HMDS). This HMDS
In the treatment, the semiconductor wafer is placed on a placing table having a built-in heating mechanism, and the HMDS gas is blown onto the wafer surface from above while heating the semiconductor wafer to a predetermined temperature, for example, 60 ° C. When the HMDS process is completed, the semiconductor wafer is then transferred to a cooling unit, where it is cooled to a temperature suitable for resist coating, for example, 23 ° C., and then the semiconductor wafer is transferred to a resist coating unit, and the above-described process is performed. A simple resist coating.

[0005]

In the conventional resist coating apparatus of this type, when performing dummy dispensing,
The dummy dispensing is started after the semiconductor wafer which is the object to be processed is carried into the resist coating section and placed on the spin chuck. Then, when the dummy dispensing is completed, the resist coating step is immediately executed.

However, the temperature of the semiconductor wafer on the spin chuck changes due to the influence of the ambient temperature during the dummy dispensing, and when the resist coating process is started, the temperature becomes different from the set temperature, and A temperature difference is apt to occur between the respective parts within the wafer surface, particularly between the central part of the wafer and the peripheral part of the wafer. Therefore, it is difficult to uniformly apply the resist with a constant film thickness in the resist applying step that is first performed after the dummy dispensing is performed.

The present invention has been made in view of the above problems, and the temperature of the object to be processed is controlled to a predetermined temperature even when the dummy dispensing is executed, so that stable and uniform resist coating can be performed. An object is to provide a resist coating device.

[0008]

In order to achieve the above object, the resist coating apparatus of the present invention is a resist coating apparatus in which the resist is ejected conditionally between the resist coating steps. It is configured to include means for completing the operation of discarding the resist at a predetermined timing before the object to be processed is carried in or loaded into the resist coating section.

[0009]

For example, when the interruption time of the resist coating operation exceeds a predetermined time due to a lot break or the like, a work of discarding a predetermined amount of the resist liquid from the resist discharging means, so-called dummy dispensing is executed. In the present invention, before the object to be processed is carried into the resist coating section, for example, prior to the resist coating step, the object to be processed is placed in a temperature adjusting mechanism that adjusts the temperature of the object to the optimum temperature for resist coating. The dummy dispensing is completed while the object to be processed is carried out from the temperature adjusting mechanism and is being carried to the resist coating section. As a result, the dummy dispensing is executed before the object to be processed is carried into the resist coating section, the dummy dispensing is completed when the object to be processed is carried into or loaded in the resist coating section, and the object is almost loaded. The resist coating process can be performed at a temperature.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a resist coating apparatus for manufacturing semiconductor devices will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic plan view showing the structure of the mechanical portion of the resist coating apparatus according to this embodiment. As shown in the figure, the resist coating apparatus includes a loader unit 10 and a processing unit 1.
It consists of 2.

The loader unit 10 is provided with a plurality of cassette elevators 14 along the left side wall surface 10a, and a plurality of cassettes 16, for example, four cassettes 16 are arranged side by side on the cassette elevators 14 toward the processing unit 12, respectively. .. Each cassette 16 can accommodate a plurality of, for example, 25 semiconductor wafers 18. At the center of the loader unit 10, a transfer mechanism 20 for loading and unloading the semiconductor wafer 18 from the cassette 16 is provided. The transfer mechanism 20 is movable between the cassette elevator 14 and the wafer transfer mechanism 22 in the Y direction parallel to the arrangement direction of the cassettes 16 and the X direction perpendicular thereto, and at an arbitrary angle on the XY plane. Tweezers 2 holding 18
0a is configured to be rotatable. Wafer transfer mechanism 2
Reference numeral 2 denotes a pair of parallel stage pins 22a for supporting the semiconductor wafer 18 and an openable and closable structure for aligning the semiconductor wafer 18 mounted on these stage pins 22a so as to sandwich the semiconductor wafer 18 from the side. It has a pair of centering guides 22b.

In the processing unit 12, in addition to the resist coating mechanism 24 for performing resist coating processing, an HMDS processing mechanism 26,
A prebake mechanism 28 and a cooling mechanism 30 are provided. The HMDS processing mechanism 26 is a treatment for making the surface of the semiconductor wafer 18 hydrophobic by using hexamethyldisilazane (HMDS) prior to the resist coating step in order to enhance the adhesion between the resist and the wafer surface (HMDS treatment).
Is to do (also called adhesion processing). The pre-baking mechanism 28 evaporates the residual solvent such as thinner in the coating film after coating the resist. The cooling mechanism 30 is a mechanism that cools the semiconductor wafer 18 after the HMDS treatment to a temperature suitable for resist coating and cools the semiconductor wafer 18 after prebaking to room temperature.

In the processing section 12, the resist coating mechanism 2
4 and HMDS processing mechanism 26 side and prebaking mechanism 28
A corridor-shaped wafer transfer chamber 32 is provided between the wafer transfer chamber 32 and the cooling mechanism 30. A transfer path 34 is provided in the wafer transfer chamber 32 in the longitudinal direction, and the wafer transfer body 36 can be moved on the transfer path 34. A transfer arm 38 is attached to the wafer transfer body 36 while supporting the semiconductor wafer 18 while being rotatable by an arbitrary angle and capable of being carried in and out of each of the mechanisms 24 to 30. The wafer carry-in / out port of each of the mechanisms 24 to 30 faces the wafer transfer chamber 32.

FIG. 2 is a block diagram showing the configuration of the control unit of the present resist coating apparatus. Resist coating controller 40,
The HMDS control unit 42, the prebake control unit 44, and the cooling control unit 46 respectively include the resist coating mechanism 24,
It is a unit that controls the operation of each part in the HMDS processing mechanism 26, the prebaking mechanism 28, and the cooling mechanism 30. The temperature control unit 48 is a unit that controls the temperature inside each of the mechanisms 24 to 30. The transfer control unit 50 controls the operation of each unit in the wafer transfer chamber 32 of the processing unit 12, especially the operation of the wafer transfer body 36 and the transfer arm 38, and also the operation of each unit in the loader unit 10, particularly the cassette elevator 14, transfer. It is a unit that controls the operations of the mechanism 20 and the wafer delivery mechanism 22. The main control unit 52 includes the control units 4
It is a system controller (main controller) that controls 0 to 50.

FIG. 3 is a diagram showing the internal construction of the resist coating mechanism 24. In the resist coating mechanism 24, a coating processing section 56 is provided inside the cup 54,
A single semiconductor wafer 18 is placed as an object to be processed on the spin chuck 58 arranged at the center of the.

The spin chuck 58 is rotated at a predetermined speed by the rotational driving force of the motor 60 while the wafer 18 is fixed and held by vacuum suction. A resist nozzle 6 movable above the wafer 18 held by the spin chuck 58.
2 is provided, and a predetermined amount of resist liquid is dropped from the nozzle 62 onto the central portion of the wafer 18. Then, the resist solution spreads to the outer peripheral edge side of the wafer by the centrifugal force and is applied onto the wafer surface. In this resist coating apparatus, since the temperature of the wafer 18 is maintained at a predetermined temperature suitable for resist coating, for example, around 23 °, a uniform resist film having a predetermined film thickness can be obtained. Note that the resist liquid scattered from the outer peripheral edge of the wafer 18 during the resist coating process hits the inner wall of the cup 54 and is guided to the bottom, and is discharged from the discharge port 54a through the drain pipe 64 to a drain tank for drainage recovery (see FIG. (Not shown).

When the resist is a highly corrosive resist such as an acidic resist, the cup 54, the spin chuck 58, the drain pipe 64, and the resist solution delivery mechanism 7 are used.
4. Use a Teflon material having excellent corrosion resistance as a constituent member that supplies the resist liquid and may come into contact with the resist liquid, such as the resist nozzle 62 and piping.
Alternatively, a product with a Teflon coating on the surface is used.

When the resist coating operation as described above is completed, a predetermined cleaning liquid is directed toward the back surface of the rotating wafer 18 from the cleaning nozzle 68 provided on the upper surface of the mounting flange 66 of the motor 60 for a predetermined time. Sprayed on the wafer 18
The resist solution sneaking around on the back surface of is washed off.
The drainage liquid by this back surface cleaning is also collected at the bottom of the cup 54 and then sent from the drain port 54a to the drain tank for drainage recovery through the drain pipe 64. The cleaning liquid ejected from the cleaning nozzle 68 is supplied from the cleaning liquid bottle 70 via the cleaning liquid delivery mechanism 72.

The resist liquid dropped from the resist nozzle 62 is supplied from a resist liquid storage bottle 76 via a resist liquid delivery mechanism 74. The resist solution delivery mechanism 74 is composed of a valve, a pump, and the like, and when performing resist application, under the condition that the wafer 18 is placed on the spin chuck 58 and the resist nozzle 62 is located above it. A fixed amount of resist liquid is delivered and dropped on the surface of the wafer 18 from the resist nozzle 62. Further, when performing the dummy dispensing, the resist solution delivery mechanism 74 operates under the condition that the resist nozzle 62 is located in the nozzle standby portion (not shown), and a predetermined amount of resist solution is delivered to the resist nozzle 62. It is becoming more and more discarded. The resist nozzle 62 is attached to or held at the tip of the arm of the nozzle scanner 78, and can be moved between the resist droplet lower position above the spin chuck 58 and the nozzle standby position by the operation of the nozzle scanner 78. .

In the resist coating mechanism 24, the motor 60, the cleaning liquid delivery mechanism 72, the resist liquid delivery mechanism 7
The operations of the nozzle 4 and the nozzle scanner 78 are controlled by the resist coating controller 40. Resist coating controller 40
The main control unit 5 controls the timing when the semiconductor wafer 18 to be coated with the resist is loaded on the spin chuck 58.
Know by the control signal from 2. Then, the motor 6
0 is operated to rotate the spin chuck 58 at a predetermined rotation speed, and while the wafer 18 on the spin chuck 58 is rotated at the same speed, the scanner 78 is operated to cause the resist nozzle 62 to drop the resist above the spin chuck 58. Then, the resist solution delivery mechanism 74 is operated to drop a predetermined amount of resist solution onto the surface of the wafer 18 from the resist nozzle 62. Then, finally, the cleaning liquid delivery mechanism 72 is operated to cause the cleaning nozzle 68 to remove the wafer 18 from the cleaning nozzle 68.
When the resist coating process is completed, the cleaning liquid is jetted toward the back surface of the substrate for a predetermined time, and a process completion signal is sent to the main controller 52.

Further, when performing the dummy dispensing, the resist coating control section 40 causes the semiconductor wafer 18 to be coated with the resist by the dummy dispensing as described later.
The main control unit 52 gives a dummy dispense execution start command so that it is completed at a predetermined timing before being carried into the resist coating mechanism 24. Upon receiving this command, the resist coating control unit 40 confirms that the resist nozzle 62 is located in the nozzle standby unit, and then activates the resist liquid delivery mechanism 74 to operate the resist nozzle 62.
A predetermined amount of resist solution is discarded. This dummy dispense is performed for a predetermined time, for example, 15 seconds. Next, the resist coating control unit 40 waits for a wafer loading timing signal from the main control unit 52, and when receiving this signal, controls each unit to execute resist coating in the same manner as above.

In this resist coating apparatus, as will be described later, the dummy dispense is performed before the semiconductor wafer 18 is loaded into the resist coating mechanism 24, for example, while being cooled by the cooling mechanism 30 or being being transported by the wafer transporter 36. Since the dummy dispensing has already been completed when the semiconductor wafer 18 is placed on the spin chuck 58, the semiconductor wafer 18 has little or no waiting time on the spin chuck 58. Wait time. As a result, even when the dummy dispensing is executed, the semiconductor wafer 18 is coated with the resist while being kept at the set temperature.

The overall operation of the resist coating apparatus will be described below. First, in the loader unit 10, the transfer mechanism 20 moves in the XY directions to move a desired one semiconductor wafer 18 from one cassette 16 on the cassette elevator 14.
Take out. At this time, the cassette elevator 14 moves up and down so that the semiconductor wafer 18 to be taken out is adjusted to the height of the transfer mechanism 20. When the transfer mechanism 20 takes out a desired semiconductor wafer 18 from the cassette 16, the transfer mechanism 20 moves to the wafer delivery mechanism 22 and delivers the semiconductor wafer 18 to the wafer delivery mechanism 22. Then, the stage pins 22a of the wafer transfer mechanism 22 come up from below to receive the semiconductor wafer 18, and then the centering guides 22b sandwich the semiconductor wafer 18 from both sides to perform alignment. At this time, the wafer transfer body 36 on the processing section 12 side is next to the wafer transfer mechanism 22, and the transfer arm 38 faces the wafer transfer mechanism 22 side. Then, the semiconductor wafer 18 aligned by the wafer transfer mechanism 22 is transferred to the transfer arm 38 of the wafer transfer body 36 and sent to the processing section 12. The operation inside the loader unit 10 and the operations of the wafer transfer body 36 and the transfer arm 38 are controlled by the transfer control unit 50.

The semiconductor wafer 18 sent to the processing section 12 by the wafer transfer body 36 is first carried into the HMDS processing mechanism 26 by the transfer arm 38, and the HMDS processing mechanism 26 is loaded there.
Received DS processing. In this HMDS process, under the control of the HMDS controller 42, the semiconductor wafer 18 is placed on a mounting table having a heating means built therein, and the wafer 18 is heated to a predetermined temperature, for example, 60 ° C. 18
It is done by spraying on the surface of.

When the HMDS processing is completed, the semiconductor wafer 18 is transferred to the HMDS processing mechanism 26 by the transfer arm 38.
Then, it is carried into the cooling mechanism 30 through the wafer transfer chamber 32 by the transfer arm 38. In the cooling mechanism 30, the semiconductor wafer 18 is cooled to a set temperature suitable for resist coating, for example, 23 ° C. Cooling mechanism 30
The semiconductor wafer 18 that has been cooled to the set temperature therein is carried out of the cooling mechanism 30 by the carrier arm 38, and then carried into the resist coating mechanism 24 by the carrier arm 38 through the wafer carrier chamber 32.

Here, the semiconductor wafer 18 is cooled by the cooling mechanism 30.
Timing to be discharged from the wafer and resist coating mechanism 2
The timing at which the paper is loaded into the transport control unit 4 is notified from the transport control unit 50 to the main control unit 52. The transfer time from when the semiconductor wafer 18 is unloaded from the cooling mechanism 30 to when it is loaded into the resist coating mechanism 24 is a time preset by a program. The main control unit 52 uses the resist coating mechanism 24.
Normally, only a timing signal for resist coating, that is, a signal indicating the timing at which the wafer 18 is loaded into the resist coating mechanism 24 is supplied to the resist control unit 40 of FIG.

However, when the condition for executing the dummy dispense is satisfied, as in the case where the resist solution is not dropped from the resist nozzle 62 for a predetermined time or longer due to a lot break or the like, the main control unit 52 causes the semiconductor wafer 18 to operate, for example. Is being cooled by the cooling mechanism 30, or when the semiconductor wafer 18 is unloaded from the cooling mechanism 30 or is being conveyed toward the resist coating mechanism 24, the resist controller 40 is instructed to start execution of dummy dispensing. Give orders. As a result, dummy dispensing is performed in the resist coating mechanism 24 in parallel with the semiconductor wafer 18 being transported in the wafer transport chamber 32. Therefore, assuming that the wafer transfer time from the cooling mechanism 30 to the resist coating mechanism 24 is, for example, 10 seconds, the semiconductor wafer 18 is carried into the resist coating mechanism 24 if the dummy dispensing is started 5 seconds before the end of cooling. The dummy dispense will be completed before As a result, since the resist coating can be performed immediately, the semiconductor wafer 18 is
The temperature does not change so much on the spin chuck 58,
The resist coating process is performed in a state where the temperature is maintained almost at the set temperature.

As described above, in the present resist coating apparatus, the resist coating can be performed while the semiconductor wafer 18 is always controlled at the set temperature regardless of the execution of the dummy dispensing, so that the resist film varies between the wafers. Alternatively, the variation can be reduced.

Semiconductor wafer 1 after resist coating processing
8 is carried out from the resist coating mechanism 24, and then carried into the pre-baking mechanism 28 by the carrying arm 38 through the wafer carrying chamber 32. In the pre-baking mechanism 28,
The semiconductor wafer 18 is placed on a hot plate and heated at a predetermined temperature, for example, 100 ° C. for a predetermined time, whereby the residual solvent is evaporated and removed from the coating film on the wafer 18. When the pre-baking is completed, the semiconductor wafer 18 is unloaded from the pre-baking mechanism 28 and then loaded into the cooling mechanism 30, where it is cooled to room temperature. Then, after being carried in from the cooling mechanism 30, it is carried to the loader unit 10 by the wafer carrier 36, and the wafer carrier 3 is transported in the reverse order of the above.
6 is returned to the cassette 16 via the wafer transfer mechanism 22 and the transfer mechanism 20.

In the above-described embodiment, when the dummy dispense is executed, the time when the semiconductor wafer 18 is being cooled by the cooling mechanism 30 is set as the start timing of the dummy dispense, but when the dummy dispense execution time is very short. Alternatively, when the wafer transfer time in the wafer transfer chamber 32 is relatively long, the dummy dispensing start timing may be set to a predetermined time point after the unloading point and before the wafer is loaded into the resist coating mechanism 24.

Further, the semiconductor wafer 18 may be kept waiting in the cooling mechanism 30 in a cooled state until the dummy dispensing is completed, and may be carried out after the dummy dispensing is completed.

For example, as shown in the flow chart of FIG. 4, when the cooling processing end time of the semiconductor wafer at the top of the lot comes, the cooling mechanism 46 sends a sending signal RTS to the main controller 52 to send the wafer. contact. The cooling process is continued.

The main control unit 46 which receives this signal RTS
Instructs the transfer control unit 50 to move to carry out the wafer for which the cooling process has been completed, and the transfer control unit 50 controls the wafer transfer body 36 to transfer the wafer.
To the front of the cooling mechanism.

Next, the main controller 52 automatically determines the unit to which the next wafer should be loaded according to a predetermined processing program, and, for example, the resist coating mechanism 24.
To decide. When the resist coating mechanism 24 can receive the wafer, the main control unit 52 transmits to the resist coating control unit 40, as lot information, for example, information that the next wafer to be processed is the first wafer in the lot.

The resist coating control unit 4 which has received this information
0 determines whether or not the dummy dispense is necessary according to a predetermined processing program, and determines that the dummy dispense is necessary, for example, and the resist coating mechanism 24
Control and start / execute the dummy dispense.

When the dummy dispensing operation is completed, the resist coating control section 40 sends a signal indicating the dummy dispensing completion report to the main control section 52. Upon receiving this signal, the main control unit 52 instructs the transfer control unit 50 to carry out the wafer being cooled by the cooling mechanism 30. Upon receipt of the instruction, the transfer control unit 50 transmits a reception signal RTR to the cooling control unit 46 to notify it of wafer reception.

Upon receiving this signal, the cooling control section 46 controls the cooling mechanism 30 to stop the cooling process. Then, the transfer control unit 50 operates the transfer arm 38,
The wafer is unloaded from the cooling mechanism 30 and loaded into the resist coating mechanism 24 for the next processing. Next, the resist coating controller 40 controls the resist coating mechanism 24 to execute resist coating.

As described above, even if the unit on the receiving side can receive the wafer, the wafer is kept waiting on the cooling mechanism 30 until the dummy dispensing is completed. In this case, since the wafer transfer time from the cooling mechanism 30 to the resist coating mechanism 24 can be made substantially constant, the temperature change that the semiconductor wafer receives due to the influence of the environment during the transfer becomes substantially constant. Therefore, at the time of resist coating, all wafers can be coated under the same temperature condition.

Although the above-described embodiment relates to the resist coating apparatus for manufacturing a semiconductor device, the present invention is not limited to this, and is applied to any resist coating apparatus having a dummy dispensing function. It is possible.

[0041]

As described above, according to the resist coating apparatus of the present invention, the dummy dispensing is completed at a predetermined timing before the object to be processed is carried in or loaded into the resist coating section. The resist coating can be executed immediately or shortly after the object to be processed is carried in or loaded into the resist coating section. This allows
The resist coating can be performed while the temperature of the object to be processed is stably maintained, and a uniform resist film having a desired film thickness can be obtained even immediately after the dummy dispensing.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing a mechanical structure of a resist coating apparatus for manufacturing a semiconductor device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a control unit of the resist coating apparatus according to the embodiment.

FIG. 3 is a perspective view showing a configuration of a resist coating mechanism in the resist coating apparatus according to the embodiment.

FIG. 4 is a flow chart for explaining an example of dummy dispensing in the resist coating apparatus according to the embodiment.

[Explanation of symbols]

 10 loader unit 12 processing unit 24 resist coating mechanism 30 cooling mechanism 32 wafer transfer chamber 36 wafer transfer body 38 transfer arm 40 resist application control unit 50 transfer control unit 52 main control unit 62 resist nozzle 74 resist liquid delivery mechanism

(72) Inventor Yasushi Hayashida 2655 Tsukyu, Kikuyo-cho, Kikuchi-gun, Kumamoto Prefecture, Tokyo Electron Kyushu Co., Ltd.

Claims (1)

[Claims] 1. A resist coating apparatus in which resist is conditionally discarded by a resist discharging unit between resist coating steps, and the object is loaded at a predetermined timing before being loaded into or loaded in the resist coating section. A resist coating apparatus comprising means for completing a resist discarding operation.