JP2004008906A - Film forming apparatus and film forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film forming system and a film forming method by which the controllability of the thickness of the film of a film forming material is improved while suppressing the quantity of the film forming material to be used. <P>SOLUTION: The film forming system is provided with a wafer holding means for holding a wafer W, a tilting means for tilting the wafer holding means, a tilt angle control means for controlling the tilt angle of the wafer holding means, a rotation means for rotating the wafer holding means as the wafer holding means is tilted and a means for controlling the number of revolution of the wafer holding means. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a film forming apparatus and a film forming method, and is particularly suitable for application when a film forming material is coated on a wafer.
[0002]
[Prior art]
In a conventional film forming apparatus, there is a method in which a wafer on which a film forming material is dropped is rotated at a high speed, and the film forming material is spin-coated on the wafer.
FIG. 6 is a side view showing a conventional film forming method.
In FIG. 6A, the film forming apparatus is provided with a wafer chuck 11 for holding a wafer W, and the wafer chuck 11 is horizontally held via a rotating shaft 12.
[0003]
When the wafer W is placed on the wafer chuck 11, the wafer W is fixed to the wafer chuck 11 by attracting the wafer W to the wafer chuck 11.
When the wafer W is fixed on the wafer chuck 1, the wafer W is rotated by rotating the wafer chuck 11, and the liquid film forming material R is dropped onto the wafer W via the nozzle 13.
[0004]
Then, when the film forming material R is dropped on the rotating wafer W, the film forming material R spreads on the wafer W by centrifugal force as shown in FIG. Material R is coated.
Then, as shown in FIG. 6C, when the film-forming material R spreads over the wafer W, excess film-forming material R ′ scattered from the edge of the wafer W to the outside due to centrifugal force, and was coated on the wafer W. The thickness of the film forming material R is made uniform.
[0005]
FIG. 7 is a flowchart showing a conventional film forming method.
In FIG. 7, when the liquid film-forming material R is dropped on the wafer W (step S31), the wafer W is rotated at a low speed, whereby the film-forming material R is expanded (step S32).
Next, when the elongation of the film forming material R progresses to some extent, the wafer W is rotated at a high speed (step S33), and the film forming material R is sufficiently spread on the outer peripheral portion of the wafer W to form a film on the entire surface of the wafer W. The thickness of the material R is made uniform to complete the film formation (step S34).
[0006]
[Problems to be solved by the invention]
However, in the conventional film forming method, the film forming material R is stretched by centrifugal force generated when the wafer W is rotated.
Therefore, in order to make the thickness of the film-forming material R uniform over the entire surface of the wafer W, the amount of the film-forming material R dropped is controlled so that the film-forming material R is sufficiently distributed to the outer periphery of the wafer W. It is necessary to increase the number of rotations of the wafer W.
[0007]
For this reason, when the film-forming material R is coated on the wafer W, the scattering amount of the film-forming material R ′ increases, and there is a problem that the consumption of the film-forming material R increases.
In particular, as the diameter of the wafer W increases, the amount of the scattered film material R ′ increases, and the cost of the film material R increases due to the increase in the diameter of the wafer.
Accordingly, an object of the present invention is to provide a film forming apparatus and a film forming method capable of improving the controllability of the film thickness of a film forming material while suppressing the consumption of the film forming material.
[0008]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a film forming apparatus configured to control a wafer holding unit that holds a wafer, a tilting unit that tilts the wafer holding unit, and a tilt angle of the wafer holding unit. Tilt angle control means, a rotation means for rotating the wafer holding means while the wafer holding means is tilted, and a rotation speed control means for controlling the rotation speed of the wafer holding means. .
[0009]
This makes it possible to rotate the wafer while the wafer is tilted, and to spread the film-forming material by gravity while changing the flow direction of the film-forming material.
For this reason, it is possible to spread the film-forming material over the entire surface of the wafer without using centrifugal force, to prevent the film-forming material from scattering, and to suppress the consumption of the film-forming material. In addition, it is possible to improve the controllability of the film thickness of the film forming material by controlling the flow state of the film forming material.
[0010]
Further, according to the film forming apparatus of the present invention, the rotation number control means controls the rotation number of the wafer holding means based on the viscosity or the volatilization rate of the film forming material dropped on the wafer. It is characterized by the following.
This makes it possible to change the flow direction based on the fluidity of the film-forming material and to control the stretching speed of the film-forming material, so that the thickness of the film-forming material on the wafer is uniform. It is possible to improve the performance.
[0011]
Further, according to the film forming apparatus of claim 3, the tilt angle control means sets the tilt angle of the wafer holding means based on a film thickness distribution or a flowing state of the film forming material dropped on the wafer. It is characterized by controlling.
This makes it possible to control the reaction rate of the film-forming material by controlling the stretching speed of the film-forming material, and to easily provide an in-plane distribution of the thickness of the film-forming material on the wafer. Become.
[0012]
According to the film forming method of claim 4, a step of dropping a film forming material on a wafer, a step of flowing the film forming material by tilting the wafer, and a step of tilting the wafer, Changing the flow direction of the film-forming material by rotating the wafer.
Thus, the film forming material can be spread by gravity while changing the flow direction of the film forming material, and the film forming material can be uniformly spread over the entire surface of the wafer without using a centrifugal force. .
[0013]
For this reason, it is possible to control the flow state of the film forming material by preventing the film forming material from scattering, and to improve the film thickness controllability of the film forming material while suppressing the consumption of the film forming material. Becomes possible.
According to the film forming method of the present invention, the step of dropping the film forming material on the wafer and the step of rotating the wafer at a low speed while the wafer is tilted to form the film formed on the wafer. Spreading the film material, shifting the wafer to a horizontal state, and rotating the wafer at a high speed while keeping the wafer horizontal, so that the film-forming material dropped on the wafer reaches the outer peripheral portion. Spreading step.
[0014]
Accordingly, after the film is formed on the inner peripheral portion by gravity, the film can be formed on the outer peripheral portion having a large area by centrifugal force, and the film forming time can be reduced.
For this reason, even when a highly volatile film-forming material is coated on a large-diameter wafer, it is possible to suppress a change in viscosity of the film-forming material and to achieve a uniform film thickness of the film-forming material.
[0015]
According to the film forming method of the sixth aspect, a step of dropping a film forming material on the wafer and rotating the wafer while tilting the wafer at a predetermined tilt angle, Spreading the dropped film-forming material, changing the tilt angle of the wafer based on the spread amount of the film-forming material, and rotating the wafer while changing the tilt angle, Further spreading the film-forming material dropped on the wafer.
[0016]
This makes it possible to change the thickness of the film-forming material by controlling the residence time of the film-forming material on the wafer and easily provide an in-plane distribution of the thickness of the film-forming material on the wafer. It becomes possible.
Therefore, even when the etching rate of the film forming material on the wafer varies, the film thickness distribution of the film forming material after etching can be made uniform.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a film forming apparatus and a film forming method according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a schematic configuration of a film forming apparatus according to one embodiment of the present invention.
[0018]
In FIG. 1, the film forming apparatus is provided with a wafer chuck 1 for holding a wafer W, and the wafer chuck 1 is coupled to a rotating shaft 2. Then, the rotation mechanism 4 rotates the wafer chuck 1 via the rotation shaft 2.
When the rotation mechanism 4 rotates the wafer W, the wafer W may be continuously rotated, or the wafer W may be rotated in a stepped manner.
[0019]
Further, the film forming apparatus is provided with a tilting mechanism 5, which tilts the wafer chuck 1 together with the rotating mechanism 4. This makes it possible to tilt the wafer chuck 1 while rotating the wafer chuck 1.
Further, a nozzle 3 for discharging the film forming material R is provided above the wafer chuck 1, and the nozzle 3 is connected to a discharging mechanism 6 for discharging the film forming material R.
[0020]
The rotation mechanism 4, the tilt mechanism 5, and the discharge mechanism 6 are connected to a film forming control unit 7, and the film forming control unit 7 controls the number of rotations of the rotation mechanism 4 and the tilt angle of the tilt mechanism 5. Further, the discharge amount and the discharge timing of the film forming material R discharged from the nozzle 3 are controlled.
As the film forming material R, for example, a photoresist, an SOG material, a Low-k material, or the like can be used. As the Low-k material, for example, a PAE (poly aryleneether) material, HSQ (hydrogen silsesquioxane), or the like. A system material, an MSQ (methyl silsesquioxane) material, a PCB material, a CF material, a SiOC material, a SiOF material, or the like can be used.
[0021]
FIG. 2 is a perspective view illustrating a film forming method according to the first embodiment of the present invention.
In FIG. 2A, when the wafer W is placed on the wafer chuck 1, the wafer chuck 1 attracts the wafer W, and fixes the wafer W on the wafer chuck 1.
When the wafer W is fixed on the wafer chuck 1, the tilt mechanism 5 tilts the wafer chuck 1, and the rotating mechanism 4 rotates the wafer chuck 1, so that the wafer W is tilted while the wafer W is tilted. Rotate.
[0022]
Then, the ejection mechanism 6 drops the liquid film-forming material R onto the wafer W via the nozzle 3. Here, the dropping position of the film forming material R is preferably the center of the wafer W when the film forming material R is uniformly applied on the wafer W.
In the case where the film forming material R has a film thickness distribution, it is preferable that the film forming material R be dropped at the center of the region where the film thickness is increased.
[0023]
When the film forming material R is dropped on the wafer W, the film forming material R flows down on the wafer W due to gravity as shown in FIG. 2B, and the film W is coated on the wafer W. You.
Here, when the film forming material R flows down on the wafer W, by rotating the wafer W, the film forming material R can be spirally spread on the wafer W without using a centrifugal force.
[0024]
Then, as shown in FIG. 2C, when the film forming material R spreads over the entire surface of the wafer W, the rotation of the wafer W is stopped, and the inclination of the wafer W is returned to a horizontal state, thereby completing the film forming.
Here, since the rotation of the wafer W is performed not for applying a centrifugal force to the film forming material R but for controlling the flow direction of the film forming material R on the wafer W, it is necessary to rotate the wafer W at a high speed. Disappears.
[0025]
Therefore, when coating the film forming material R on the wafer W, it is possible to prevent the film forming material R from scattering from the edge of the wafer W, and it is possible to suppress the consumption of the film forming material R.
Note that the rotation speed and the tilt angle of the wafer W can be set based on the viscosity and the volatilization rate of the film forming material R, and are set such that the thickness of the film forming material R is uniform on the wafer W. Is preferred.
[0026]
Further, while coating the film-forming material R on the wafer W, it is possible to change the flow direction and the residence time of the film-forming material R by controlling the rotation speed and the inclination angle of the wafer W, It is possible to easily control the film thickness distribution of the film forming material R on the wafer W.
FIG. 3 is a flowchart showing a film forming method according to the first embodiment of the present invention.
[0027]
In FIG. 3, the wafer W is placed on the wafer chuck 1 and the rotation axis 2 of the wafer chuck 1 is inclined to tilt the wafer chuck 1 (step S1). Then, while the wafer chuck 1 is inclined, the wafer chuck 1 is rotated at a low speed (step S2). The rotation speed of the wafer chuck 1 can be set to, for example, several rpm.
[0028]
Next, the liquid film-forming material R is dropped on the wafer W, and the film-forming material R is extended on the wafer W (step S3). The rotation of the chuck 1 is stopped, and the inclination of the wafer W is returned to the horizontal state, thereby completing the film formation of the film forming material R (Step S4).
Accordingly, it is possible to spread the film forming material R by gravity while changing the flow direction of the film forming material R, and to coat the film forming material R on the wafer W while preventing the film forming material R from scattering. Becomes possible.
[0029]
FIG. 4 is a flowchart illustrating a film forming method according to the second embodiment of the present invention.
In FIG. 4, the wafer W is placed on the wafer chuck 1 and the rotation axis 2 of the wafer chuck 1 is inclined to incline the wafer chuck 1 (step S1). Then, while the wafer chuck 1 is inclined, the wafer chuck 1 is rotated at a low speed (step S12). The rotation speed of the wafer chuck 1 at this time can be set to, for example, several rpm.
[0030]
Next, the liquid film forming material R is dropped on the wafer W, and the film forming material R is expanded on the wafer W (step S13), and the film forming material R is applied to the inner peripheral portion of the wafer W. Then, the inclination of the wafer W is returned to the horizontal position (step S14), and the wafer chuck 1 is rotated at a high speed (step S15). At this time, the rotation speed of the wafer chuck 1 can be set to, for example, 6000 rpm.
[0031]
Then, when the film-forming material R is applied to the outer peripheral portion of the wafer W, the rotation of the wafer chuck 1 is stopped, and the film-forming of the film-forming material R is completed (Step S16).
This makes it possible to form the film-forming material R on the inner peripheral portion of the wafer W by gravity and then form the film-forming material R on the outer peripheral portion having a large area by centrifugal force. The film time can be reduced.
[0032]
For this reason, even when a highly volatile film-forming material R is coated on a large-diameter wafer W, it is possible to suppress a change in viscosity of the film-forming material R and to make the film thickness of the film-forming material R uniform. It becomes possible.
FIG. 5 is a flowchart illustrating a film forming method according to the third embodiment of the present invention.
In FIG. 5, the wafer W is placed on the wafer chuck 1 and the rotation axis 2 of the wafer chuck 1 is inclined to incline the wafer chuck 1 (step S21). Then, the wafer chuck 1 is rotated at a low speed while the wafer chuck 1 is inclined (step S22).
[0033]
Next, the liquid film forming material R is dropped on the wafer W, and the film forming material R is expanded on the wafer W (step S23), and the film forming material R is applied to the inner peripheral portion of the wafer W. Then, the elongation of the film forming material R is continued by controlling the inclination angle of the wafer W (step S24).
When the film-forming material R is applied to the outer peripheral portion of the wafer W, the rotation of the wafer chuck 1 is stopped, and the wafer chuck 1 is returned to a horizontal position to complete the film-forming of the film-forming material R (step S25). ).
[0034]
This makes it possible to change the thickness of the film forming material R by controlling the residence time of the film forming material R on the wafer W during the film forming of the film forming material R. The in-plane distribution of the thickness of the material R can be easily provided.
Therefore, even when the etching rate of the film forming material R varies when the film forming material R is etched after the film formation, the film thickness distribution of the film forming material R after the etching can be made uniform. It becomes.
[0035]
For example, when the film forming material R is etched back when the outer peripheral portion of the wafer W has a higher etching rate than the inner peripheral portion of the wafer W, when the film forming material R is coated on the wafer W, At times, the inclination of the wafer W can be reduced in the middle.
This makes it possible to make the thickness of the film forming material R at the outer peripheral portion of the wafer W larger than that at the inner peripheral portion of the wafer W, and offsets the film thickness distribution of the etching rate at the time of etching back the film forming material R. can do.
[0036]
In the above-described embodiment, the method of controlling the film thickness distribution of the film forming material R on the wafer W by controlling the tilt angle and the number of rotations of the wafer W has been described. The flow of the film forming material R can be changed not only by the inclination angle and the rotation speed of the wafer W, but also by the viscosity of the film forming material R, the evaporation rate of the solvent, and the like.
For this reason, by controlling the temperature of the wafer W, the viscosity of the film forming material R and the volatilization rate of the solvent may be changed to control the film thickness distribution of the film forming material R.
[0037]
【The invention's effect】
As described above, according to the present invention, it is possible to spread the film forming material while controlling the flow state of the film forming material by rotating the wafer while the wafer is tilted. The controllability of the film thickness of the film forming material can be improved while suppressing the consumption of the film.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of a film forming apparatus according to an embodiment of the present invention.
FIG. 2 is a perspective view showing a film forming method according to the first embodiment of the present invention.
FIG. 3 is a flowchart showing a film forming method according to the first embodiment of the present invention.
FIG. 4 is a flowchart illustrating a film forming method according to a second embodiment of the present invention.
FIG. 5 is a flowchart illustrating a film forming method according to a third embodiment of the present invention.
FIG. 6 is a side view showing a conventional film forming method.
FIG. 7 is a flowchart showing a conventional film forming method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Wafer chuck 2 Rotation shaft 3 Nozzle 4 Rotation mechanism 5 Inclination mechanism 6 Discharge mechanism 7 Film formation control unit W Wafer R Film formation material

Claims (6)

Wafer holding means for holding a wafer;
Tilt means for tilting the wafer holding means,
Tilt angle control means for controlling the tilt angle of the wafer holding means,
Rotating means for rotating the wafer holding means while keeping the wafer holding means inclined,
A film forming apparatus comprising: a number-of-revolutions control means for controlling the number of revolutions of the wafer holding means. 2. The film forming apparatus according to claim 1, wherein the rotation number control unit controls the rotation number of the wafer holding unit based on a viscosity or a volatilization rate of the film forming material dropped on the wafer. 3. 3. The tilt angle control unit according to claim 1, wherein the tilt angle control unit controls the tilt angle of the wafer holding unit based on a film thickness distribution or a flow state of a film forming material dropped on the wafer. Film forming equipment. Dropping a film-forming material on the wafer;
Flowing the film-forming material by tilting the wafer;
Changing the flow direction of the film-forming material by rotating the wafer while the wafer is tilted. Dropping a film-forming material on the wafer;
Spreading the film-forming material dropped on the wafer by rotating the wafer at a low speed while the wafer is tilted;
Transferring the wafer to a horizontal state;
A step of rotating the wafer at a high speed while keeping the wafer horizontal, thereby spreading a film-forming material dropped on the wafer to an outer peripheral portion. Dropping a film-forming material on the wafer;
Spreading the film-forming material dropped on the wafer by rotating the wafer while tilting the wafer by a predetermined tilt angle;
Changing the tilt angle of the wafer based on the spread amount of the film forming material;
Rotating the wafer while changing the tilt angle to further spread the film-forming material dropped on the wafer.

Images