JP3970695B2 - Resist application method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
This invention relates to a resist coating process for applying a registry on the surface of a substrate such as a semiconductor wafer.
[0002]
[Prior art]
Conventionally, when a processing solution such as a resist is applied to the surface of a substrate, the processing solution is supplied near the center of rotation of the substrate that rotates at high speed in a plane parallel to the main surface, and the processing solution is spread by centrifugal force. A spin coating method is used in which a treatment liquid is applied to the entire surface of the substrate. However, this spin coating method has a problem that a large amount of resist is required before the entire surface of the substrate is covered with the processing liquid.
[0003]
For this reason, Japanese Patent Laid-Open No. 2000-350955 and Japanese Patent Laid-Open No. 2001-113217 describe a nozzle that rotates a substrate and discharges a processing liquid from the tip of the nozzle, and a position where the tip faces the rotation center of the substrate. A processing liquid coating method is disclosed in which a processing liquid is applied to the entire surface of a substrate by moving the tip between the position facing the edge of the substrate.
[0004]
[Problems to be solved by the invention]
Depending on the surface condition of the substrate, the wettability with the resist on the surface of the substrate may be poor. For this reason, in the above-described conventional processing liquid coating method, uncoated resist or uneven coating occurs in the vicinity of the rotation center of the substrate or in other areas of the substrate surface, and a uniform film of the processing liquid is formed on the surface of the substrate. There is a problem that it cannot be formed.
[0005]
Further, in the above-described conventional processing liquid coating method, there is a problem in that the untreated coating of the processing liquid occurs in the vicinity of the rotation center of the substrate due to a difference between the timing of discharging the processing liquid from the nozzle and the movement timing of the nozzle. .
[0006]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a resist coating method capable of uniformly coating a resist over the entire surface of a substrate without requiring a large amount of resist. .
[0007]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a substrate rotating step of rotating the substrate at a first rotation speed in a plane parallel to the main surface, and an edge of the substrate rotating the nozzle while discharging the resist from the nozzle. A first application step of applying a resist to the surface of the substrate by moving from a position facing the rotation center to a position facing the rotation center, and a rotation center of the substrate rotating the nozzle while discharging the resist from the nozzle. A second coating step in which a resist is applied to the surface of the substrate by stopping at the facing position, and a position facing the edge from a position facing the rotation center of the substrate rotating the nozzle while discharging the resist from the nozzle. a third coating step of coating a resist on the surface of the substrate by moving toward the stops the discharge of the resist from the nozzle, the substrate By rotating at a faster second rotational speed than said at the main surface and a plane parallel first rotation speed, it has a film thickness adjustment step of forming a uniform thin film of resist to a surface of the substrate It is characterized by.
[0008]
According to a second aspect of the present invention, in the first aspect of the invention, the nozzle includes a plurality of resist discharge portions arranged in a direction intersecting a tangential direction of a circle centered on the rotation center of the substrate. ing.
[0009]
According to a third aspect of the present invention, in the first or second aspect of the invention, the substrate is rotated at a third rotational speed that is slower than the first rotational speed in the second coating step.
[0010]
According to a fourth aspect of the present invention, in the first aspect of the present invention, the first rotation speed is 100 rpm to 800 rpm.
[0011]
The invention according to claim 5 is the invention according to any one of claims 1 to 3, wherein the second rotation speed is 1000 rpm to 3500 rpm.
[0012]
According to a sixth aspect of the present invention, in the first aspect of the present invention, the third rotational speed is 100 rpm to 300 rpm.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a side view schematically showing the configuration of a resist coating apparatus to which the present invention is applied, and FIG. 2 is a plan view thereof.
[0014]
This resist coating apparatus includes a spin chuck 13 that holds the back surface of the substrate W by suction. The spin chuck 13 is connected to the motor 11 via the shaft 12. For this reason, the substrate W rotates in a plane parallel to the main surface while being attracted and held by the spin chuck 13 by driving the motor 11.
[0015]
Further, the substrate processing apparatus is provided with a nozzle 17 for supplying Les resist on the surface of the substrate W. The nozzle 17 is connected to an arm 16 that swings about a shaft 15 by driving a motor 14. For this reason, the nozzle 17 is rotated by the drive of the motor 14 as shown in FIG. 1 and FIG. 2 at the position facing the edge of the rotating substrate W, and in FIG. 1 and FIG. Horizontal movement between the position facing the rotation center of the substrate W and the position facing the other edge of the rotating substrate W shown in FIG. 1 and FIG. 2C in parallel with the main surface of the substrate W To do.
[0016]
FIG. 3 is an explanatory diagram showing the configuration of the nozzle 17. 3A is a view showing the back surface of the nozzle 17, and FIG. 3B is a view showing a cross section of the nozzle 17.
[0017]
The nozzle 17 includes a main body 22 having a hollow portion 23 inside. The hollow portion 22 is connected to a resist supply pipe line 27 through flow paths formed in the pair of rotation angle adjusting members 24 and 25 and the fixing member 26. The resist supply conduit 27 is connected to a resist supply unit (not shown) via an on-off valve 28.
[0018]
Six resist discharge portions 21 are arranged at a constant pitch on the lower surface of the main body 22 in the nozzle 17. Each resist discharge portion 21 has a resist discharge port connected to the hollow portion 23 of the main body 22. The main body 22 can be adjusted in its rotational angle position by the action of the pair of rotational angle adjusting members 24 as shown by arrows in FIG. For this reason, the angular position of the six resist discharge portions 21 arranged on the lower surface of the main body 22 in the row direction can be adjusted.
[0019]
FIG. 4 is an explanatory diagram for explaining the angular positions of the six resist ejection units 21 in the row direction.
[0020]
In the state shown in FIG. 4, the angle between the outer circumference of the substrate W, that is, the normal line standing on the tangent line of the circle centering on the rotation center of the substrate, and the arrangement direction of the six resist discharge portions 21 is θ. ing. In this state, the angle that intersects the tangential direction of the outer periphery of the substrate W in the direction in which the six resist ejection portions 21 are arranged (that is, a circle centered on the rotation center of the substrate W) is [90 degrees−θ]. It becomes. Then, by rotating the main body 22 by the action of the rotation angle adjusting member 24 described above and adjusting the angle θ, a tangent to a circle centering on the rotation center of the substrates W in the direction in which the six resist discharge portions 21 are arranged. It is possible to adjust the angle that intersects the direction.
[0021]
In the nozzle 17 shown in FIG. 3, six resist discharge portions are arranged at a constant pitch. For this reason, the resist is supplied from the nozzle 17 to the substrate W at a constant pitch. Then, the resist supplied at a constant pitch is spread over the entire surface of the substrate W in a film thickness adjusting process described later.
[0022]
At this time, it is preferable to adjust the pitch of the resist supplied to the substrate W according to the viscosity of the resist and the wettability of the substrate W. For this reason, in this substrate processing apparatus, by adjusting the angle intersecting the tangential direction of the circle centered on the rotation center of the substrate W in the direction in which the six resist ejection portions 21 are arranged, the substrate is supplied to the substrate W. The configuration is used to adjust the pitch of the resist .
[0023]
FIG. 5 is a block diagram showing the main electrical configuration of the resist coating apparatus described above.
[0024]
The resist coating apparatus includes a control unit 30 having a ROM 31 that stores an operation program necessary for controlling the apparatus, a RAM 32 that temporarily stores data and the like during control, and a CPU 33 that executes a logical operation. The control unit 30 is connected to the on-off valve 28 and the motors 11 and 14 described above via an interface 34. The controller 30 controls the rotation speed of the spin chuck 13, the swing speed of the arm 16, and the discharge timing of the resist from the nozzle 17.
[0025]
More specifically, during one rotation of the substrate W held by the spin chuck 13, the direction of the tangential direction of the circle centering on the rotation center of the substrate W in the six ejection units 21 of the nozzle 17 is perpendicular. The rotation speeds of the motor 11 and the motor 14 are controlled by the control unit 30 so that the nozzle 17 moves by the width L (see FIG. 4). The opening / closing operation of the opening / closing valve 28 is controlled by the control unit 30 in accordance with the position of the nozzle 17 with respect to the substrate W held and rotated by the spin chuck 13.
[0026]
Next, a description will be given resist coating operation for applying a resist to the substrate W by using the resist coating apparatus described above. 6 and 7 are flowcharts showing a resist coating operation for applying a resist to the substrate W by using the resist coating apparatus described above.
[0027]
When performing the resist coating operation on the substrate W, the nozzle 17 is disposed at a position facing the edge of the substrate W held by the spin chuck 13 indicated by (A) in FIGS.
[0028]
In this state, the substrate W is rotated at a first rotation speed in a plane parallel to the main surface by driving the spin chuck 13 (step S1). The first rotation speed is preferably about 100 rpm to 800 rpm.
[0029]
Then, the on-off valve 28 is opened to discharge the resist from the nozzle 17 (step S2), and the arm 16 is swung to move the nozzle 17 toward the center of rotation of the substrate W (step S3). In this state, since the rotational speed of the substrate W is on the order of 100rpm to 800 rpm, without using a large amount resist, it is possible to appropriately supply the resist to the surface of the substrate W.
[0030]
If the nozzle 17 moves to a position facing the rotation center of the substrate W shown in FIG. 1 and FIG. 2B (step S4), the movement of the nozzle 17 is stopped (step S5), and the spin chuck 13 By driving, the substrate W is rotated at the third rotation speed (step S6).
[0031]
The third rotation speed is preferably about 100 rpm to 300 rpm. In this state, a necessary amount of resist is supplied from the stopped nozzle 17 near the rotation center of the substrate W where uneven application of resist is likely to occur. Then, by setting the rotation speed of the substrate W at this time to 100 rpm to 300 rpm, it is possible to reduce the diffusion action due to the centrifugal force of the resist applied in the vicinity of the rotation center of the substrate W.
[0032]
If a time of about 0.1 to 1 second elapses in this state (step S7), the nozzle 17 is moved from the position facing the rotation center of the substrate W shown in FIG. 1 and FIG. (C), the substrate is moved toward a position facing the edge of the substrate W held by the spin chuck 13 (step S8). Further, the rotation speed of the substrate W by the spin chuck 13 is again set as the first rotation speed (step S9). In this state, since the rotational speed of the substrate W is on the order of 100rpm to 800 rpm, without using a large amount resist, it is possible to appropriately supply the resist to the surface of the substrate W.
[0033]
When the nozzle 17 reaches a position facing the edge of the substrate W held by the spin chuck 13 shown in FIG. 1 and FIG. 2C (step S10), the nozzle is closed by closing the on-off valve 28. The discharge of the resist from the nozzle 17 is stopped (step S11), and the movement of the nozzle 17 is stopped (step S12).
[0034]
Then, by driving the spin chuck 13, the substrate W is rotated at a second rotation speed in a plane parallel to the main surface (step S13). The second rotation speed is preferably about 1000 rpm to 3500 rpm. As a result, the resist supplied to the surface of the substrate W is spread on the surface of the substrate W by the force of centrifugal force, and a uniform thin film of resist is formed on the surface of the substrate W.
[0035]
When a certain time has elapsed (step S14) and a uniform resist thin film is formed on the surface of the substrate W, the spin chuck 13 stops rotating (step S15) and the resist coating operation is terminated.
[0036]
In the embodiment described above, the nozzle 17 is moved from the position facing the edge of the substrate W held by the spin chuck 13 shown in FIG. 1 and FIG. And then moved to a position facing the other edge of the substrate W held by the spin chuck 13 shown in FIG. 1 and FIG. 2C. I am letting. However, as shown in FIGS. 8 and 9, the nozzle 17 is moved from the position facing the edge of the substrate W held by the spin chuck 13 shown in FIG. After being moved to a position facing the rotation center of the substrate W shown in (B), again to a position facing the edge of the substrate W held by the spin chuck 13 shown in (A) in FIGS. You may make it return.
[0037]
In the embodiment described above, the nozzle 17 is swung on an arc centered on the shaft 15 as the arm 16 swings. However, the nozzle 17 is held by the spin chuck 13. The substrate W may be moved linearly in the diameter direction of the rotating substrate W.
[0038]
【The invention's effect】
According to the first to sixth aspects of the invention, it is possible to uniformly apply the resist over the entire surface of the substrate without requiring a large amount of resist.
[0039]
According to the third aspect of the present invention, it is possible to reliably apply the resist near the rotation center of the substrate where unpainted portions or the like are likely to be left behind.
[Brief description of the drawings]
FIG. 1 is a side view schematically showing a configuration of a resist coating apparatus to which the present invention is applied.
FIG. 2 is a plan view schematically showing a configuration of a resist coating apparatus to which the present invention is applied.
FIG. 3 is an explanatory diagram showing a configuration of a nozzle 17;
FIG. 4 is an explanatory diagram for explaining the angular positions of six resist ejection units 21 in the row direction.
FIG. 5 is a block diagram showing a main electrical configuration of the resist coating apparatus.
FIG. 6 is a flowchart showing a resist coating operation.
FIG. 7 is a flowchart showing a resist coating operation.
FIG. 8 is a side view schematically showing a configuration of a resist coating apparatus to which another embodiment of the present invention is applied.
FIG. 9 is a plan view schematically showing a configuration of a resist coating apparatus to which another embodiment of the present invention is applied.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Motor 12 axis | shaft 13 Spin chuck 14 Motor 15 axis | shaft 16 Arm 17 Nozzle 21 Resist discharge part 22 Main body 23 Hollow part 24 Rotation angle adjustment member 25 Rotation angle adjustment member 26 Fixing member 27 Resist supply pipe 28 Opening / closing valve 30 Control part W substrate

Claims (6)

A substrate rotation step of rotating the substrate at a first rotation speed in a plane parallel to the principal surface;
While discharging the resist from the nozzle, and a first coating step of coating a resist on the surface of the substrate by moving toward a position where the center of rotation opposite from a position edge facing the substrate rotating the nozzle,
A second application step of applying a resist to the surface of the substrate by discharging the resist from the nozzle and stopping the nozzle at a position facing the rotation center of the rotating substrate;
A third application step of applying a resist to the surface of the substrate by moving the nozzle from a position facing the rotation center of the rotating substrate toward a position facing the edge while discharging the resist from the nozzle;
The resist discharge from the nozzle is stopped, and the substrate is rotated at a second rotation speed higher than the first rotation speed in a plane parallel to the main surface thereof, whereby the resist is uniformly formed on the surface of the substrate. A film thickness adjusting step for forming a thin film ;
A resist coating method comprising: The resist coating method according to claim 1,
The nozzle is a substrate processing method comprising a plurality of resist discharge portions arranged in a direction intersecting a tangential direction of a circle centering on a rotation center of the substrate. In the resist coating method according to claim 1 or 2,
In the second coating step, a resist coating method in which the substrate is rotated at a third rotational speed that is slower than the first rotational speed. In the resist application method according to any one of claims 1 to 3, a resist coating method the first rotational speed is 100rpm to 800 rpm. In the resist coating method according to any one of claims 1 to 3, a resist coating method and the second rotational speed is 1000rpm to 3500 rpm. In the resist coating method according to any one of claims 1 to 2, a resist coating method wherein the third rotational speed is 100rpm to 300 rpm.

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