TWI552192B - Coating film formation method, coating film formation device, and storage medium - Google Patents

Description

Coating film forming method, coating film forming device, and memory medium

The present invention relates to a technical field of forming a coating film by supplying a coating liquid to a substrate on which a concave pattern is formed.

In the photoresist step of one of the semiconductor processes, a step of applying a photoresist to a surface of a substrate such as a semiconductor wafer, performing exposure and development to form a photoresist pattern, and coating the photoresist by a general spin coating Coated and coated.

With the recent high density of semiconductor circuits, we have reviewed components with more complicated 3-dimensional structures. In the case of manufacturing these elements, there is a case where a step of locally etching is performed in a concave pattern formed on the substrate, and a photoresist is applied to the inside of the concave pattern.

Further, in the etching step, there is a case where the etching selectivity to the etching target of the photoresist film is small, and therefore there is a demand for the photoresist film to be a thick film of, for example, a μm order. In order to make the photoresist film thick, it is necessary to use, for example, a high viscosity of 400 cP or more as a photoresist. However, when a photoresist having a small fluidity is applied to a fine concave pattern formed on a substrate, it is difficult to embed the inside of the concave pattern only by the stretching action by centrifugal force, and the residual void is present. .

When the voids remain in the concave pattern on the lower side of the coating film, the thickness of the coating film may be uneven, or the gas in the void may be expanded during heat treatment of the substrate, and bubbles may be mixed into the coating film. doubt.

According to the technique described in Patent Document 1, a coating liquid having a high viscosity is applied to a substrate on which a concave pattern is formed, and then a bubble in a concave pattern is removed in a reduced-pressure gas atmosphere. However, in such methods, there is a need for a mechanism for decompression, which causes problems such as an increase in size of the apparatus.

[Practical Technical Literature]

[Patent Literature]

Patent Document 1: Japan Special Open 2009-10147

In view of the above problems, an object of the present invention is to provide a coating film having a high-viscosity coating liquid on a substrate having a concave pattern formed thereon, and to spread the coating liquid into the concave pattern to obtain a good coating. The method of cloth film.

In the method for forming a coating film of the present invention, a substrate having a concave pattern formed on a surface thereof is formed by spin coating to form a coating film, comprising the steps of: holding the substrate horizontally in the substrate holding portion; The first solvent supply step of supplying the solvent to the center portion of the substrate by the solvent nozzle and rotating the substrate at the first rotation speed to diffuse the solvent by centrifugal force to wet at least the surface of the substrate other than the concave pattern; a second solvent supply step of supplying a solvent to the central portion of the substrate and rotating the substrate at a second rotation speed which is slower than the first rotation speed, and moisturizing the solvent in the concave pattern; and thereafter, from the coating liquid nozzle to the substrate The step of supplying the coating liquid to the center portion and rotating the substrate to diffuse the coating liquid by centrifugal force.

In the coating film forming apparatus of the present invention, a substrate having a concave pattern formed on the surface thereof is formed by spin coating to form a coating film, and is characterized by comprising: a substrate holding portion that horizontally holds the substrate; a rotating mechanism that rotates the substrate holding portion about a vertical axis; a solvent nozzle that supplies a solvent to the substrate; and a coating liquid nozzle that supplies a coating film for forming a coating film on the substrate a coating liquid; and a control unit configured to: supply a solvent to a central portion of the substrate, rotate the substrate at a first rotation speed, and diffuse the solvent by centrifugal force to remove at least a surface of the substrate other than the concave pattern a first solvent supply step of wetting; a second solvent supply step of supplying a solvent to a central portion of the substrate and rotating the substrate at a second rotation speed which is slower than the first rotation speed to wet the solvent in the concave pattern; Then, a coating liquid is supplied to the center portion of the substrate to rotate the substrate, and the coating liquid is diffused by centrifugal force.

In the computer-readable recording medium of the present invention, a computer program for performing substrate coating is provided, and the computer program is provided with a substrate holding portion, a solvent nozzle, and a coating liquid nozzle, and the substrate is held by the substrate holding portion by rotation An apparatus for applying a coating liquid onto a substrate is characterized in that the computer program is a combination of a step group to carry out the above-described coating film forming method.

According to the present invention, when a high-viscosity coating liquid is applied by spin coating on a substrate having a concave pattern, the substrate is rotated at a high speed and pre-wetted with a solvent before applying the coating liquid, and secondly, The substrate is rotated at a low speed to pre-wet. By performing this two-stage pre-wetting, the solvent is filled in a state in which the concave pattern is filled. Therefore, when the coating liquid is subsequently stretched on the surface of the wafer W, the viscosity of the coating liquid is lowered by mixing with the filled solvent in the concave pattern, and it is easy to enter the concave pattern. Therefore, voids are not left in the concave pattern after the application of the coating film, and a favorable coating film is obtained.

1‧‧‧ concave pattern

10‧‧‧矽 substrate

11‧‧‧Metal pads

12‧‧‧ LSI (component)

13‧‧‧Adhesive (pressing agent) layer

14‧‧‧glass support layer

15‧‧‧SiO ₂ film

16‧‧‧through holes

2‧‧‧ cup body module

21‧‧‧Rotating chuck

22‧‧‧Rotary axis

23‧‧‧Rotating mechanism

24‧‧‧ cup body

25‧‧‧Draining road

26‧‧‧Exhaust road

3‧‧‧Nozzle unit

31‧‧‧Solvent nozzle

32‧‧‧Light resistance nozzle

33, 34‧‧‧ supply pipe

35‧‧‧Solvent supply mechanism

36‧‧‧Light resistance supply agency

37‧‧‧ Robotic arm

38‧‧‧Mobile

39‧‧‧rails

41‧‧‧Standby busbar

5‧‧‧Solvent

6‧‧‧Photoresist

9‧‧‧Control Department

W‧‧‧ wafer

Fig. 1 is a cross-sectional view showing the surface structure of a substrate used in an embodiment of the present invention.

Fig. 2 is a view showing the structure of a photoresist coating apparatus according to an embodiment of the present invention.

Fig. 3 is a perspective view showing a photoresist coating apparatus according to an embodiment of the present invention.

Fig. 4 is an explanatory view showing a solvent supply step of the method for forming a coating film of the present invention.

Fig. 5 is an explanatory view showing a solvent supply step of the method for forming a coating film of the present invention.

Fig. 6 is an explanatory view showing a solvent supply step of the method for forming a coating film of the present invention.

Fig. 7 is an explanatory view showing a solvent supply step of the method for forming a coating film of the present invention.

Fig. 8 is an explanatory view showing a photoresist coating step of the coating film forming method of the present invention.

Fig. 9 is an explanatory view showing a photoresist coating step of the coating film forming method of the present invention.

Fig. 10 is an explanatory view showing a concave pattern of a solvent to be supplied.

Fig. 11 is an explanatory view showing a state in which the coating liquid penetrates into a concave pattern.

Fig. 12 is an explanatory view showing a coating film filled in a concave pattern.

Figure 13 shows a cross-sectional view of a photoresist pattern formed on a wafer.

Figure 14 is a cross-sectional view showing a through hole formed in a wafer.

[Best Mode for Carrying Out the Invention]

As an embodiment in which the coating film forming method of the present invention is used, an embodiment of a method of forming a photoresist pattern in an intermediate stage of a manufacturing process of a three-dimensional semiconductor integrated circuit will be described. Fig. 1 shows the surface structure of a substrate at the middle of the manufacturing process of the 3-dimensional semiconductor integrated circuit.

First, the substrate is briefly described. A substrate W is laminated on the glass support layer 14 via a bonding agent (pressing agent) layer 13 to form, for example, a wafer W having a thickness of 100 μm. 16 is a through hole, 11 is a metal pad made of copper or aluminum, 12 is an LSI (element), and 15 is an SiO ₂ film. The through holes were formed in a columnar shape having an opening diameter of 70 μm and a depth of 100 μm, and the arrangement was set such that the separation interval was 300 μm in a lattice shape (at the intersection of the lattices). The substrate used in the embodiment of the present invention is intended to be a substrate having a concave pattern. However, in this example, the hole (concave portion) corresponds to a concave pattern as viewed from the wafer W, that is, from the wafer W. In this specification, the concave pattern series is a hole or a groove.

An example of a method for forming a coating film according to the present invention will be described with respect to a method of applying a photoresist coating device for applying a photoresist to a wafer W. First, the photoresist coating device (equivalent In the embodiment of the coating film forming apparatus of the present invention, the photoresist coating apparatus includes the cup module 2 and the nozzle unit 3. As shown in FIGS. 2 and 3, the cup body module 2 includes a rotary chuck 21 that holds a substrate holding portion that horizontally holds the center portion of the back surface of the wafer W, and the rotary chuck 21 extends vertically. The rotating shaft 22 is connected to the rotating mechanism 23. The rotation mechanism 23 is provided with a rotation drive source such as a rotary motor (not shown), and is configured to be rotatable at a predetermined speed. A cup body (in detail, a cup assembly) 24 having an opening is provided on the upper side so as to surround the wafer W on the spin chuck 21 around the spin chuck 21. The cup body 24 is configured to receive the solvent removed from the wafer W, discharge it from the lower liquid discharge path 25, and exhaust the gas from the lower exhaust path 26 so that the mist does not scatter into the processing gas atmosphere.

As shown in FIG. 3, the nozzle unit 3 is configured to include a robot arm 37, a moving body 38, a lifting mechanism (not shown), and a moving mechanism of the guide rail 39, and a spouting position and a cup above the center portion of the wafer W. The standby bus bars 41 outside the body 24 move between. At the front end of the nozzle unit 3, a solvent nozzle 31 and a photoresist nozzle 32 which is a coating liquid nozzle are provided. The solvent nozzle 31 and the photoresist nozzle 32 are connected to the solvent supply mechanism 35 and the photoresist supply mechanism 36 via supply pipes 33 and 34, respectively. The solvent supply mechanism 35 and the photoresist supply mechanism 36 include, for example, a pump, a valve, a filter, and the like, and are configured to eject a predetermined amount of solvent and a photoresist from the front ends of the solvent nozzle 31 and the photoresist nozzle 32, respectively. In addition, in FIG. 3, in order to avoid complication, the supply pipes 33 and 34, the solvent supply mechanism 35, and the photoresist supply mechanism 36 which extended the upper part of the nozzle unit 3 are abbreviate|omitted. In the embodiment of the present invention, as the photoresist for forming a coating film, for example, a photoresist having a high viscosity of 400 cP is used, and a thick coating film having a thickness of about 100 μm is formed by a photoresist coating step to be described later. . As the solvent, for example, PGME (propylene glycol monomethyl ether), PGMEA (propylene glycol monomethyl ether acetate), a mixture thereof, or the like is used.

A control unit 9 composed of, for example, a computer is provided in the photoresist coating device. The control unit 9 has a program storage unit, and the program storage unit stores a program for commanding the transfer of the wafer W between the external transfer arm and the rotary chuck 21 or the rotation of the rotary chuck 21, Supply procedure for photoresist and solvent. This program is attached to the control unit 9 by, for example, a memory such as a flexible disk, a compact disk, a hard disk, an MO (magnetic disk), or a memory card.

Next, the action of the coating film forming method of the embodiment of the present invention using the above-described photoresist coating apparatus will be described. The wafer W on which the concave pattern 1 (in this example, a hole) as shown in FIG. 1 is formed is carried into the photoresist coating device by a transfer arm (not shown) provided outside the photoresist coating device. The wafer W is placed on the spin chuck 21 by the cooperation of the transport arm and the three lift pins (not shown) that protrude from the spin chuck 21 . Then, the nozzle unit 3 is moved so that the solvent nozzle 31 is positioned above the center portion of the wafer W.

Thereafter, as shown in FIG. 4, the wafer W is rotated at a first number of revolutions of, for example, 3000 rpm, and a first solvent supply step of supplying a solvent 5, for example, 10 seconds, to the center portion of the wafer W from the solvent nozzle 31 is performed. The supplied solvent 5 is extended from the center of the wafer W toward the edge portion by the centrifugal force generated by the high-speed rotation of the wafer W, and the entire surface of the wafer W is wetted. Alternatively, the wafer W may be rotated after the solvent is supplied from the solvent nozzle 31 to the center portion of the wafer W.

When the first number of revolutions is too slow, it is difficult to have high uniformity spread over the entire surface due to irregularities on the surface of the wafer W. Therefore, the first number of revolutions is preferably, for example, 1,500 rpm or more. Although the upper limit of the first number of revolutions is not determined, if the degree of turbulence in the vicinity of the outer edge of the wafer W is too large, the solvent 5 is not uniformly wetted, and it should be set in consideration of this point. . Further, the time during which the solvent is supplied and the wafer W is rotated at the first number of revolutions may be any time sufficient to allow the solvent to diffuse to the entire surface of the wafer W, for example, 10 seconds or longer.

At the end of the first solvent supply step, at least the surface of the wafer W other than the inside of the concave pattern 1 is wetted, that is, the liquid film of the solvent 5 is formed. When the first solvent supply step is performed such that the solvent 5 is diffused to the entire surface of the wafer W and the liquid film of the solvent 5 is formed on the wafer W, the solvent 5 cannot fill the concave pattern 1, so the next step That is, the second solvent supply step is necessary. Therefore, the first solvent supply step can be said to be a step for moisturizing at least the entire surface of the wafer W other than the inside of the concave pattern 1.

In this example, the concave pattern 1 is a hole as described above, and the opening diameter of the hole is, for example, a small aperture of 70 μm. Therefore, if the solvent 5 is diffused at a high speed on the surface of the wafer W, it falls into the concave pattern 1. Previously passed above the concave pattern (hole) 1. Therefore, if observed microscopically, there is a portion of the concave pattern 1 where the solvent 5 does not enter, or the proportion of the solvent 5 that enters but the concave pattern 1 remains. Small part.

Next, as shown in FIG. 5, a second solvent supply step is performed from the solvent nozzle 31 to supply the solvent 5 to the center portion of the wafer W, and to reduce the number of revolutions of the wafer W to, for example, the second number of revolutions of 10 rpm. By reducing the number of revolutions of the wafer W, the centrifugal force acting on the solvent 5 is lowered, and the solvent 5 is concentrated on the wafer W, and the concentrated portion gradually diffuses gradually. Therefore, the residence time of the solvent 5 per unit area of the surface of the wafer W becomes long, the solvent 5 easily enters the inside of the concave pattern 1, and the solvent 5 fills the concave pattern 1. In the first solvent supply step, when the centrifugal force applied to the solvent 5 discharged to the wafer W is too small, the concentrated portion of the solvent 5 does not uniformly spread toward the outer edge of the wafer W. On the contrary, if the centrifugal force applied to the solvent 5 is excessively large, the flow of the solvent 5 toward the outer edge of the wafer W is too fast, and the solvent 5 becomes difficult to enter the concave pattern 1. Therefore, the second number of rotations is preferably, for example, 10 to 100 rpm. Further, the implementation time of the second solvent supply step may be longer than the time at which the concentrated portion of the solvent reaches the outer edge of the wafer W. Therefore, for example, it may be 10 seconds or longer.

In the second solvent supply step, the solvent 5 is ejected toward the center portion of the wafer W from the solvent nozzle 31 provided above the wafer W. Therefore, the supply amount of the solvent 5 increases in the vicinity of the center portion of the wafer W, and the solvent 5 easily enters the inside of the concave pattern 1. On the other hand, the amount of supply of the solvent in the portion farther from the center of the wafer W becomes smaller, so that the size and depth of the concave pattern 1 formed near the edge of the wafer W, and the density of the arrangement are further increased. The possibility that the solvent 5 does not sufficiently enter the inside of the concave pattern 1 is caused.

Therefore, it is preferable to carry out the third solvent supply step and the fourth solvent supply step described below, and in the same embodiment, the steps are also described. In the third solvent supply step, the second solvent supply step is continued, and as shown in FIG. 6, the solvent nozzle 31 is moved from the center portion of the wafer W to the edge side in a state where the solvent 5 is discharged.

After the solvent nozzle 31 is moved to the edge side of the wafer W, the number of revolutions of the wafer W is raised to, for example, 100 rpm, and the state is maintained for, for example, 10 seconds. The third solvent supply step is performed to compensate for the shortage of the supply amount of the solvent 5 in the vicinity of the edge portion of the wafer W in the second solvent supply step, so that the ejection position of the solvent 5 is located on the wafer W. Edge side. Therefore, dissolve The ejection position of the agent 5 should preferably cover a region where the supply amount of the solvent 5 is significantly insufficient. From this point of view, the wafer W is 12 Å, that is, a portion which is, for example, about 0.5 cm from the edge of the wafer W.

By supplying the solvent 5 from the upper solvent nozzle 31 at the edge side of the wafer W, the supply amount of the solvent 5 at the edge side portion of the wafer W is increased, so that the solvent becomes easy to enter the wafer W. The inside of the concave pattern 1 near the edge.

Then, as shown in FIG. 7, the solvent nozzle 31 is used to maintain the ejection solvent 5, and moves from the edge portion side of the wafer W toward the upper portion, and then the rotation speed of the wafer W is lowered to 10 rpm which is the second rotation speed. A fourth solvent supply step of supplying the solvent 5 to the center portion of the wafer W. When the fourth solvent supply step is described in other respects, the second solvent supply step is again performed. Further, in this example, the third solvent supply step and the fourth solvent supply step are repeated, for example, twice.

In particular, the infiltration of the solvent 5 into the concave pattern 1 in the central region of the wafer W can be more reliably performed by performing the fourth solvent supply step, and the solvent is also in the concave pattern in the vicinity of the edge of the wafer W. 1 fills the role of the help. In this way, it is determined whether or not the third solvent supply step is performed, or the third solvent supply step is followed by the fourth solvent supply step, and the third solvent supply step and the fourth solvent supply step are repeatedly performed. The size, depth, arrangement density, etc. of the concave pattern 1 on the surface of the circle W, and the viscosity of the coating liquid and the target film thickness of the coating film in the coating step in which the solvent 5 is pre-wetted (self-contained) The film thickness of the surface of the wafer W in the portion of the step is performed. In addition, the inventors of the present invention grasped the case where the third solvent supply step and the fourth solvent supply step were effective by the prior evaluation experiment.

After the supply process of the solvent 5 is completed, the rotation speed of the wafer W is raised to, for example, 500 rpm, and the excess solvent 5 is removed to complete the pre-wet. When the solvent 5 is supplied to the wafer W by the above-described steps, the solvent 5 fills the inside of the concave pattern 1, and the entire surface of the inside of the concave pattern 1 including the wafer W is covered with the solvent 5. When the number of revolutions of the wafer W is increased and the excess solvent 5 is removed, the solvent 5 remains in the concave pattern 1 and the surface of the wafer W is wetted by the solvent 5. When the photoresist liquid used in the coating step which is carried out after the pre-wet is mixed with the solvent 5, the viscosity is lowered, and the amount of the ruthenium-removing photoresist which is applied during the spin coating of the photoresist is applied, and the photoresist film is heated. The situation of the increase in membrane reduction is a concern. Therefore, by fully dissolving After the agent 5 is infiltrated into the concave pattern 1, the excess solvent 5 is removed, and the viscosity of the photoresist film is suppressed from becoming low.

After the pre-wet is finished, spin coating of the photoresist film is performed. As shown in FIG. 8, the photoresist liquid nozzle 32 is moved above the center portion of the wafer W, and the discharge of the photoresist 6 is applied to the center portion of the wafer W. After the supply of the photoresist 6 is started, the number of revolutions of the wafer W is increased, for example, it is raised to 1500 rpm, and this state is maintained for 10 seconds. With this treatment, the photoresist 6 is covered by the centrifugal force to cover the surface of the wafer W. After the photoresist 6 was diffused, the supply of the photoresist 6 was stopped as shown in FIG. 9, and the number of revolutions of the wafer W was reduced to 100 rpm and rotated for 10 seconds.

Here, the estimation mechanism of the photoresist 6 filled in the concave pattern 1 when the photoresist W is applied to the pre-wetted wafer W will be described. Further, the wafer W shown in FIGS. 10 to 12 only shows the shape of the concave pattern 1, and the detailed configuration is omitted.

As shown in FIG. 10, the pre-wet wafer W remains in the concave pattern 1 and the surface of the wafer W is wetted by the solvent 5. When the high-viscosity photoresist liquid 6 is supplied to the wafer W and rotated, as shown in FIG. 11, the photoresist liquid 6 is fused with the solvent 5 of the wet coating portion to increase fluidity and become easy to crystallize. The flow on the circle W uniformly spreads on the surface of the wafer W. The photoresist 6 diffused on the surface of the wafer W also flows into the concave pattern 1 formed on the wafer W. However, since the solvent 5 is present in the concave pattern 1, it is further mixed by the solvent. The fluidity easily spreads to every corner in the concave pattern 1. In the pre-wetting described above, the solvent 5 is filled in such a manner that voids are not formed in the concave pattern 1 in advance, so that the photoresist liquid 6 is filled in the concave pattern 1 as shown in FIG. .

Further, after the photoresist 6 is applied and spread on the surface of the wafer W, the supply of the photoresist 6 is stopped, and it is rotated at a low speed of, for example, 100 rpm for 10 seconds. When the rotation speed is fast and the centrifugal force is large, there is a concern that the photoresist liquid 6 does not enter the concave pattern 1 and flows on the surface of the wafer W, but by reducing the rotation speed and reducing the centrifugal force, the photoresist liquid is made. 6 becomes easier to enter the concave pattern 1. Further, the liquid film of the photoresist 6 is planarized by slowly rotating the wafer W. Then, the rotation speed of the wafer W is raised to, for example, 500 rpm, and the photoresist film is subjected to so-called enthalpy drying.

The wafer W on which the photoresist film is formed is heated, and the excess solvent 5 in the photoresist film is volatilized, and then exposed and developed to form SiO at the bottom of the through-concave pattern 1 shown in FIG. ₂ A photoresist pattern having a diameter of 20 μm through the hole of the film 15. Thereafter, a through hole as shown in FIG. 14 is formed by performing an etching process to expose the metal pad 11 provided under the wafer W.

According to the above embodiment, when the high-viscosity photoresist 6 is applied by spin coating to the wafer W on which the concave pattern 1 is formed, the wafer W is transferred before the photoresist 6 is applied. Rotating to pre-wet with solvent 5, and secondly rotating wafer W at a low speed to pre-wet. The surface of the wafer W is wetted by the solvent 5 by the stretching of the solvent 5 at a high speed, so that the solvent 5 to be supplied is easily diffused. Then, by rotating the wafer W at a low speed and stretching the solvent 5 on the surface of the wafer W, the solvent 5 is concentrated on the wafer W, and since the residence time on the wafer W becomes long, the solvent is obtained. 5 becomes easy to fill the concave pattern 1 inside. Therefore, the photoresist 6 which is extended on the surface of the wafer W is mixed with the filled solvent 5 to lower the viscosity, and it is easy to enter the concave pattern 1.

The third solvent supply step is performed by the solvent nozzles 31 used in the first and second solvent supply steps in the above embodiment, but a nozzle different from the solvent nozzle 31 may be used (hereinafter, "outer nozzle") Call it). In this case, the outer nozzle is placed on the upper side near the edge portion of the wafer W, and the solvent is ejected from the outer nozzle toward the edge of the wafer W immediately before the end of the second solvent supply step. When the outer nozzle is used as described above, the time zone in which the solvent 5 is ejected from the center portion of the wafer W from the solvent nozzle 31 overlaps with the timing from the outer nozzle ejecting solvent 5, and the state in which the solvent 5 is not supplied to the wafer W should be avoided. Appearance.

As the outer nozzle, a porous body is provided at the end of the nozzle, and the porous body may be supplied with the solvent 5 in a shower form from the porous body. The solvent supply position on the wafer W as the third solvent supply step is preferably closer to the outer edge than the straight line along the line connecting the center of the wafer W and the outer edge, but The surface state of the circle W may be a position closer to the center of the wafer W than the 2 bisector.

Further, after the third solvent supply step is performed using the outer nozzle, the center of the wafer W is applied. In the fourth solvent supply step of supplying the solvent 5, it is preferable to superimpose the time zone from the outer nozzle discharge solvent 5 and the timing from the solvent nozzle to the center portion of the wafer W. Further, the solvent nozzle that performs the fourth solvent supply step may be provided separately from the solvent nozzle 31 that performs the first and second solvent supply steps.

Further, in the embodiment of the present invention, a positive resist liquid coating method is used, but a negative photoresist liquid may be applied. Further, as a coating liquid having a high viscosity applied to the wafer W, it may be a polyimide or an adhesive for bonding the wafer W.

[Examples]

In order to evaluate the present invention, the following evaluation test was carried out using the photoresist coating apparatus according to the embodiment of the present invention. The wafer W (diameter 12 吋) concave pattern 1 was set such that the opening diameter of the surface of the wafer W was 70 μm and the hole having a depth of 100 μm was located at the intersection of the lattices, and the separation interval between the wafers was set to 300 μm. In any of the examples, the photoresist 6 is a positive-type high-viscosity photoresist (1000 cP), and the solvent 5 used for pre-wetting is PGMEA.

[Example 1]

As the pre-wet, the following first to fourth solvent supply steps are performed in this order, and the third solvent supply step and the fourth solvent supply step are performed once. The coating of the photoresist 6 is then carried out.

(first solvent supply step)

The wafer W was rotated at 3000 rpm, and the solvent 5 was supplied to the center portion of the wafer W at a flow rate of 10 cc / sec for 10 seconds.

(Second solvent supply step)

The wafer W was rotated at 10 rpm, and the solvent 5 was supplied to the center portion of the wafer W for 10 seconds.

(third solvent supply step)

The solvent nozzle 31 is maintained from the solvent nozzle 31, and the solvent nozzle 31 is moved from the center of the wafer W to the position close to the center side by 0.5 cm from the edge of the wafer W, and then the wafer W is rotated at 100 rpm, and the solvent is used. 5 supply for 10 seconds.

(fourth solvent supply step)

The solvent nozzle 31 is maintained from the solvent nozzle 31, and the solvent nozzle 31 is placed on the center of the wafer W. After the square was moved, the wafer W was rotated at 10 rpm, and the solvent 5 was supplied for 10 seconds. The discharge flow rate of the solvent 5 in the second solvent supply step, the third solvent supply step, and the fourth solvent supply step is the same as the first solvent supply step.

[Embodiment 2]

In the pre-wet of Example 1, after the second solvent supply step is performed, the application of the photoresist 6 is performed.

[Comparative Example 1]

The pre-wet was applied in the same manner as in Example 1 except that the first solvent supply step was not performed, and then the application of the photoresist 6 was performed.

[Comparative Example 2]

The photoresist layer 6 is applied without pre-wet.

[Verification test]

The wafer W subjected to the treatment of Comparative Example 2 produced voids in almost all of the concave patterns 1, and the generation of bubbles was observed in the photoresist film. The wafer W wafer W subjected to the treatment of Example 2 was removed from the concave pattern 1 of the portion other than the edge portion of the wafer W, and the filling property of the photoresist was improved, and no voids or bubbles were observed. However, a region of 0.5 cm from the edge of the wafer W was found to form a concave pattern 1 of voids. It can be said that the filling property of the photoresist film is improved by supplying the solvent 5 to the center portion of the wafer and slowly rotating it.

In the wafer W subjected to the treatment of Comparative Example 1, the improvement of the filling property was observed in almost all of the concave patterns 1, and the solvent was supplied by maintaining the supply solvent 5 and moving the solvent nozzle 31 toward the edge of the wafer W. The supply of 5 can more fully cover the entire surface and improve the filling of the photoresist film.

In the wafer W subjected to the treatment of Example 1, the improvement in the filling property was observed in almost all of the concave patterns 1, and the filling property was better as compared with Comparative Example 1. It can be said that before the solvent is filled in the concave pattern 1 of the wafer W, the entire surface of the wafer W is wetted with the solvent 5, whereby the filling property of the photoresist film is further improved. According to the method for forming a coating film according to the embodiment of the present invention, it can be said that the coating film is formed by applying a coating liquid having a high viscosity, and the filling property of the coating film can be greatly improved.

1‧‧‧ concave pattern

5‧‧‧Solvent

6‧‧‧Photoresist

W‧‧‧ wafer

Claims (21)

A coating film forming method for forming a coating film by spin coating on a substrate having a concave pattern on a surface thereof, comprising the steps of: a substrate holding step of holding the substrate horizontally at the substrate holding portion; In the first solvent supply step, a solvent is supplied from a solvent nozzle to a central portion of the substrate, and the substrate is rotated at a first number of rotations to diffuse the solvent by centrifugal force, thereby at least removing the surface of the substrate other than the concave pattern; and then (2) a solvent supply step of supplying a solvent from a solvent nozzle to a central portion of the substrate, rotating the substrate at a second rotation speed which is slower than the first rotation speed, and wetting the inside of the concave pattern with a solvent; and then applying the liquid diffusion step, The coating liquid nozzle supplies a coating liquid to the center portion of the substrate, rotates the substrate, and diffuses the coating liquid by centrifugal force. The coating film forming method according to claim 1, wherein the coating liquid has a viscosity of 400 cP or more. The coating film forming method according to claim 1 or 2, wherein the target film thickness of the coating film is 1 μm or more. The method for forming a coating film according to claim 1 or 2, wherein the first number of revolutions is from 1,000 to 4,000 rpm. The method for forming a coating film according to claim 1 or 2, wherein the second number of revolutions is 10 to 100 rpm. The method for forming a coating film according to claim 1 or 2, further comprising: a third solvent supply step, wherein the second solvent supply step is performed to rotate the substrate and approach the edge from the center portion of the substrate The position of the spit solvent. The method of forming a coating film according to the sixth aspect of the invention, wherein the second solvent supply step is followed by a state in which the solvent is ejected from the solvent nozzle, and the supply portion of the solvent is moved from the center portion of the substrate toward the edge side. The third solvent supply step is performed by the solvent nozzle. The method for forming a coating film according to claim 6, further comprising: a fourth solvent supply step, wherein the substrate is rotated to eject a solvent toward a central portion of the substrate in the third solvent supply step. The method for forming a coating film according to claim 7 of the patent application scope further comprises: In the fourth solvent supply step, in the third solvent supply step, the solvent is ejected from the solvent nozzle, and the supply portion of the solvent is moved from the edge side of the substrate toward the center portion. The method for forming a coating film according to the eighth aspect of the invention, wherein the third solvent supply step is further performed after the fourth solvent supply step. A coating film forming apparatus comprising a substrate having a concave pattern formed on a surface thereof, and a coating film formed by a spin coating method, comprising: a substrate holding portion for holding the substrate horizontally; and a rotating mechanism for the substrate The holding portion is rotated about a vertical axis; a solvent nozzle supplies a solvent to the substrate; a coating liquid nozzle supplies a coating liquid for forming a coating film on the substrate; and a control unit for performing the following steps: the first solvent In the supplying step, the solvent is supplied to the center portion of the substrate, the substrate is rotated at the first number of rotations, and the solvent is diffused by the centrifugal force to wet at least the surface of the substrate other than the concave pattern; and then the second solvent supply step is performed. The solvent is supplied to the center portion of the substrate, and the substrate is rotated at a second rotation speed which is slower than the first rotation speed, and is wetted with a solvent in the concave pattern. Thereafter, the coating liquid is diffused to supply the coating liquid to the center portion of the substrate. And rotating the substrate to spread the coating liquid by centrifugal force. The coating film forming apparatus according to claim 11, wherein the coating liquid has a viscosity of 400 cP or more. The coating film forming apparatus according to claim 11 or 12, wherein the target film thickness of the coating film is 1 μm or more. The coating film forming apparatus according to claim 11 or 12, wherein the first number of revolutions is from 1,000 to 4,000 rpm. The coating film forming apparatus according to claim 11 or 12, wherein the second number of revolutions is 10 to 100 rpm. The coating film forming apparatus according to claim 11 or 12, wherein the control unit performs the third solvent supply step in the second solvent supply step to rotate the substrate from the center of the substrate Spray solvent near the edge. The coating film forming device of claim 16, wherein The third solvent supply step is performed by the solvent nozzle in the second solvent supply step, in which the solvent is ejected from the solvent nozzle, and the solvent supply portion is supplied from the center portion of the substrate. The edge side moves. The coating film forming apparatus according to claim 16, wherein the control unit performs a fourth solvent supply step in which the substrate is rotated while the substrate is rotated toward the center of the substrate. Solvent. The coating film forming apparatus according to claim 17, wherein the control unit is connected to the third solvent supply step to perform a fourth solvent supply step of maintaining a state in which the solvent is ejected from the solvent nozzle and causing the solvent The supply portion moves from the edge side of the substrate to the center portion. The coating film forming apparatus according to claim 18, wherein the control unit further performs the third solvent supply step after the fourth solvent supply step. A memory medium in which a computer program for a substrate application device including a substrate holding portion, a solvent nozzle, and a coating liquid nozzle is provided, and the substrate is held in the substrate holding portion, and the coating liquid is applied by spin coating. The memory medium is characterized in that the computer program includes a step group for performing the coating film forming method according to any one of claims 1 to 10.