JPH08107056A - Method of levelling of resist film - Google Patents

Abstract

PURPOSE: To provide the method of leveling of a resist film by which a lower layer resist film which is free from a pin-hole, the film unevenness, etc., and is satisfactorily levelled regardless of the type of a stepped substrate. CONSTITUTION: In order to level a lower resist film in a resist pattern forming process, first. after resist made of organic polymer material having a relatively high molecular weight is applied to a stepped substrate 10 by spin-coating, the resist is cured by a heat treatment or the exposure to ultraviolet radiation to form a lower resist film first layer 11. Then O-cresol novolac made of organic polymer material having a low molecular weight about 1000 is applied to the lower resist film first layer 11 by spin-coating to form a lower resist film second layer 12. Then the lower resist film second layer 12 is levelled by a heat treatment at a temperature of 180 deg.C-220 deg.C at which the resist film shows the fluidity to form a leveled lower resist film second layer 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of planarizing a lower resist film in a method of forming a resist pattern used in a semiconductor device manufacturing process.

[0002]

2. Description of the Related Art In recent years, as semiconductor devices have become highly integrated,
The technical requirements for forming a fine pattern are becoming more and more severe. Under such circumstances, a multilayer resist is advantageous for forming a fine pattern on a stepped substrate, and the lower layer resist film used for this plays a role of planarization and a role of a substrate etching mask.

Regarding such flattening of the lower resist film, there are those disclosed in, for example, JP-A-62-279630 and JP-A-5-61206. In the method of planarizing the lower resist film described above, as shown in FIG. 6, a photoresist made of a naphthoquinonediazide compound is spin-coated about 0.5 μm, baked at a low temperature (about 110 ° C.), and then exposed to ultraviolet light over the entire surface. By irradiating, the first layer 2 is formed on the stepped substrate 1, and the same steps are repeated to form the second layer 3 and the third layer 4 so that the layers are laminated.

[0004]

However, in the above-mentioned conventional method of forming a multilayer resist, (1) since the photoresist material itself made of a naphthoquinonediazide compound has poor fluidity due to heat treatment,
The flattening is not so good. (2) In order to obtain a desired film thickness (for example, about 1.5 μm), each forming layer must be formed as a thin film (in this case, about 0.5 μm), and in the case of a thin film, rotation is required. Flatness does not improve much during application.

(3) In order to perform sufficient planarization, it is necessary to stack three or more lower layer resist films, which increases the number of steps,
There is a problem that the throughput is reduced. Also,
When the polystyrene resin and the novolac resin synthesized with a low molecular weight (Mw of about 2000 or less) are formed on the stepped substrate 6 as the lower layer resist 5 as a material having good flatness because of good fluidity by heat treatment, There is a problem that pinholes 7 as shown in FIG. 7 are generated depending on the type of material of the base substrate and the heat treatment temperature.

The present invention eliminates the above-mentioned problems, and a resist flattening method capable of forming a good flattened lower layer resist film free from pinholes, film unevenness, etc. regardless of the type of stepped substrate. The purpose is to provide.

[0007]

In order to achieve the above object, the present invention provides: (1) In a method of flattening a lower resist film in forming a resist pattern, an organic polymer material having a relatively high molecular weight on a stepped substrate. A spin coating of a resist consisting of 1 and then cured by heat treatment or ultraviolet irradiation to form a lower resist film first layer; and a molecular weight of 1 on the lower resist film first layer.
000 to form a lower resist film second layer by spin-coating a resist composed of a low molecular weight organic polymer material, and heat treating the lower resist film second layer at a temperature having thermal fluidity And a step of planarizing the second layer of the lower resist film.

(2) In the resist flattening method described in (1) above, the organic polymer material having a molecular weight of about 1000 is O-cresol novolac, and the processing temperature for heat flow is 180 ° C to 220 ° C. . (3) In a method of flattening a lower resist film in forming a resist pattern, a step of adsorbing and forming a carbonyl compound on a stepped substrate by spin coating, and an organic polymer material having a molecular weight of about 1000 on the substrate on which the carbonyl compound is adsorbed and formed And a step of flattening the lower resist film by subjecting the lower resist film to a temperature rising process in a temperature region having thermal fluidity.

(4) In the resist flattening method described in (3) above, the organic polymer material having a molecular weight of about 1000 is O-cresol novolac, and the temperature rising region for heat flow is 150 ° C to 220 ° C. is there. (5) In a method of flattening a lower resist film in forming a resist pattern, a step of adsorbing and forming a carbonyl compound on a stepped substrate by spin coating, and an organic polymer material having a molecular weight of about 1000 on the substrate on which the carbonyl compound is adsorbed and formed Forming a lower layer resist film by spin coating a resist consisting of, and flattening the lower layer resist film by performing a multi-step heat treatment from the low temperature side to the high temperature side in the temperature region having thermal fluidity. And the process of
And cooling the substrate on which the lower resist film is formed during each of the multi-step heat treatments.

(6) In a method of flattening a lower resist film in forming a resist pattern, a step of adsorbing and forming a carbonyl compound on a stepped substrate by spin coating, and a molecular weight of 100 on the substrate on which the carbonyl compound is adsorbed and formed.
A step of forming a lower resist film by spin-coating a resist made of about 0 organic polymer material, and a heat treatment condition for flattening the lower resist film are performed in a temperature range having thermal fluidity using a lamp annealing furnace. And a step of flattening the lower resist film by repeating flash flushing for a short time.

[0011]

According to the present invention, since it is configured as described above, (1) According to the invention described in (1) or (2) above, regardless of the type of the stepped substrate, pinholes, film unevenness, etc. It is possible to form a favorable flattened lower layer resist film.

(2) According to the invention described in (3) or (4) above, in addition to the effect of (1) above, a good flattening lower layer resist film is formed also on the edge portion of the substrate step portion. Therefore, the cost and the number of steps can be reduced. (3) According to the invention described in (5) above, similarly to the above (1) and (2), it is possible to form a well-planarized lower resist film without pinholes, film unevenness, and the like. You can

(4) According to the invention described in (6) above, the flattening property by flushing baking largely depends on the baking temperature and the interval of flushing, but like O-cresol novolac, the temperature range of heat fluidity is high. (Molecular weight 10
O-cresol novolac of about 00 has a temperature of 170 ° C to 2
At a temperature of about 20 ° C.), in a polymer material in which a thermal cross-linking reaction takes place in a competitive reaction, it is better to increase the flushing interval as the treatment is performed on the higher temperature side of the heat fluidity temperature range.
The same effect as cooling in each of the multi-step heat treatments of the above (3) can be obtained, and by reducing the thermal crosslinking reaction, it is possible to form a lower layer resist film with improved planarization.

Further, in the case of a polymer material having a large thermal fluidity such as O-cresol novolac, heat treatment from the resist surface such as baking in a lamp annealing furnace is more preferable than heat treatment from a substrate like hot plate baking. However, the adhesion to the substrate is good, and the lower layer resist film free from pinholes and film unevenness can be formed without applying the surface active agent of the substrate used in the above (2) and (3).

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a resist forming process showing a first embodiment of the present invention. (1) First, as shown in FIG. 1 (a) or (a '),
A resist is spin coated on the step substrate 10 to form a lower resist film first layer 11. This lower resist film 1st layer 1
1 is preferably a photoresist composed of a relatively high molecular weight novolak resin having a low heat melting property or a naphthoquinonediazide compound, but any organic polymer material having a thermosetting property or a photocuring property may be used. However, the desired film thickness (for example, about 1.5 to 2.0 μm)
When it is necessary, the spin coating can be performed, and it is better that the film is as thin as possible, and it is preferably about 0.30 to 0.50 μm.

Next, as shown in FIG. 1 (a), the lower resist film first layer 11 is thermally cured by high temperature heat treatment on the hot plate 20, or as shown in FIG. 1 (a ').
The entire surface is irradiated with the ultraviolet rays 21 to be photo-cured. (2) Next, as shown in FIG. 1B, a resist is spin-coated on the lower layer resist film first layer 11, and the lower layer resist film second layer 12 is formed into a desired film thickness (for example, about 1.5 μm). )Form. Here, the lower resist film first layer 11 is a solvent (eg, ECA, contained in the lower resist film second layer 12).
It has only to be cured to such an extent that it has resistance to (PGMEA, EL, etc.), and the conditions of the heat treatment temperature and the ultraviolet irradiation amount are
Depends on the type of polymer material. For example, molecular weight 10
BCR (trade name,
When Tokyo Ohka Co., Ltd.) is applied to the lower resist film first layer 11, heat treatment may be performed on the hot plate 20 at about 200 to 250 ° C. for about 1 to 5 minutes.

When HPR-204 (trade name, manufactured by Fuji Hunt) is applied as a photoresist consisting of a naphthoquinonediazide compound, it is subjected to the same heat treatment as above or a HW lamp of 250 W to 500 to 1000 mJ /
The lower resist film first layer 11 having solvent resistance can be formed by irradiating the entire surface with ultraviolet rays 21 of about cm ² . Since the lower resist film first layer 11 is an organic polymer material having a relatively high molecular weight, it has low meltability during heat treatment or ultraviolet irradiation, and pinholes or film unevenness due to condensation during thermal crosslinking or photocrosslinking. Does not occur.

Further, since the lower resist film second layer 12 has good fluidity due to heat treatment, it is desirable to use a polystyrene resin or novolac resin synthesized with a low molecular weight (Mw of about 1000) which is excellent in flattening. FIG. 2 shows the planarization characteristics of O-cresol novolac at each temperature of 200 ° C. when heat-treated. In FIG. 2, the horizontal axis indicates the pattern width (μ
m), the surface step (μm) is shown on the vertical axis.
0 (triangle) and resist molecular weight 3000 (square) are shown respectively. From this figure, the resist molecular weight 100
It can be seen that 0 (circle) has no surface step and is flattened.

(3) Next, as shown in FIG. 1C, a heat treatment is carried out on a hot plate 22 to form a flattened lower layer resist film on the lower layer resist film first layer 11 with good flatness. The second layer 13 can be formed. The heat treatment temperature condition that causes fluidity for planarization varies depending on the type of organic polymer material and the size of the molecular weight,
For example, when O-cresol novolac having a molecular weight of about 1000 is applied to the lower resist film second layers 12 and 13, heat treatment is performed at 180 to 220 ° C. for about 1 to 5 minutes to achieve good planarization. Lower resist film Second layer 1
3 can be formed.

This heat treatment temperature of 180 to 220 ° C. is as shown in FIG.
As shown in, the area a has a large fluidity. That is, in FIG. 3, the horizontal axis shows the baking temperature (° C.) and the vertical axis shows the surface step (μm), and the surface step (μm) is the smallest for all the patterns at the heat treatment temperatures of 180 to 220 ° C. This lower resist film second layer 12, 13
The higher the molecular weight of the organic polymer material used for the heat treatment, the better the fluidity due to the heat treatment, and the better the flatness. On the other hand, as can be seen from FIG. Condensation due to surface tension of molecules becomes large, and pinholes and film unevenness occur depending on the type of stepped substrate. However, by forming an organic polymer material on the lower resist film first layer 11, the surface of the melted polymer Condensation due to tension can be suppressed, and a favorable flattening lower resist film second layer 13 can be formed regardless of the type of the stepped substrate.

Although the second layer 12 of the lower resist film can be planarized by the method described above, when it is used as the lower layer film of the lower resist film, the solvent contained in the upper resist film (for example, , ECA, PGMEA, EL etc.)
Must be resistant to. In the case of O-cresol novolak having a molecular weight of about 1000, 180 to 22
At the heat treatment temperature of 0 ° C., the thermal fluidity reaction is more dominant, but the thermal crosslinking reaction also occurs as a competitive reaction. For example, at the heat treatment temperature of 180 ° C., about 30 minutes, at the heat treatment temperature of 220 ° C. A lower resist film showing solvent resistance can be formed in about a minute.

Further, the lower resist film second layer 12 is formed into 18
After flattening at a heat treatment temperature of 0 ° C to 220 ° C, 230 ° C
The flattening lower resist film second layer 13 having solvent resistance can also be formed by performing the treatment at a temperature at which the thermal crosslinking reaction is dominant. Here, the lower limit of the molecular weight of O-cresol novolac of about 1000 will be described.

FIG. 4 shows the solvent resistance characteristics of O-cresol novolac with respect to the baking temperature, and FIG. 5 shows the solvent resistance characteristics of O-cresol novolac with respect to the molecular weight. From FIG.
It can be seen that the higher the baking temperature, the shorter the time required for the solvent resistance and the faster the thermal crosslinking reaction. As mentioned above,
From FIG. 3, a certain amount of heat flow time is required for the flattening, and at a baking temperature of 230 ° C. or higher, the heat flow time is short, and thus the flattening stops halfway.

From FIG. 5, the smaller the molecular weight of O-cresol novolac, the longer the time required for solvent resistance.
It is assumed that, when baked at 0 ° C., Mw1000 has solvent resistance in about 10 minutes, whereas Mw500 requires 60 minutes or more. Also, when baking at a temperature higher than 200 ° C., for example 220 ° C.
Even with cresol novolac, the solvent resistance can be shortened to about 20 minutes, but since it has a low molecular weight, the rate of occurrence of film unevenness and pinholes due to thermal condensation increases as the temperature is increased.

In the first embodiment, the O-cresol novolak was explained, but the material used for the planarization is not limited to O-cresol novolak, and m
Any phenol resin containing-, p-cresol novolac or a derivative thereof and having a low molecular weight of about 1000 may be used. However, the thermal fluidity temperature and the flattening characteristics are slightly different depending on the molecular structure and the molecular weight.

As described above, according to the first embodiment, in the flattening of the lower resist film in the multilayer resist, the lower resist film first layer is made of a relatively high molecular weight organic polymer material on the step substrate. It is formed by spin-coating and heat (or light) curing the resist, and the second layer of the lower resist film is formed by spin-coating a low molecular weight organic polymer material with a molecular weight of about 1000 and has thermal fluidity. Since the method of flattening by heat treatment at a temperature is used, it is possible to form a good flattening lower layer resist film without pinholes, film unevenness, etc., regardless of the type of the stepped substrate.

Next, a second embodiment of the present invention will be described. FIG. 8 is a sectional view of a resist forming process showing the second embodiment of the present invention. (1) First, as shown in FIG.
A carbonyl compound 32 (for example, acetone, MEK, etc.) as a surface-active agent for the substrate is adsorbed and formed by spin coating on the stepped substrate 31, thereby surface-activating the stepped substrate 31.

(2) Next, as shown in FIG. 8B, the lower layer resist film 33 is formed by spin coating the same organic polymer material as the second layer of the lower layer resist film shown in the first embodiment. To do. (3) Next, as shown in FIG. 8C, the heat treatment temperature for flattening the lower resist film 33 is gradually increased from about 150 ° C. to about 200 ° C. with the hot plate 41 capable of raising the temperature. By performing the heat treatment (for example, 5 ° C./minute), the good planarization lower layer resist film 34 could be formed.

As described above, the surface of the stepped substrate 31 is activated as compared with the case where the lower resist film 33 is directly spin-coated and flattened by heat treatment without activating the surface of the stepped substrate 31. By doing so, condensation due to the surface tension of the melted polymer during heat treatment can be reduced, pinholes, film unevenness, etc. can be reduced, and the heat treatment temperature for flattening is a temperature with high fluidity (for example, 200 ° C.). Compared with the case of the treatment of No. 1, the temperature rise treatment was gradually performed and the fluidity was gradually increased, so that pinholes, film unevenness and the like could be suppressed. The temperature raising process for flattening can be naturally applied to the first embodiment, but particularly in the second embodiment, the effect is great on the edge portion of the step portion.

When O-cresol novolak (molecular weight of about 1000) is used as the lower resist film, HMDS (hexamethylene disilazane) which is usually used for patterning a photoresist is used as a surfactant.
If used, the adhesion to the substrate deteriorates during heat treatment,
A flat lower resist film could not be formed. Therefore, in the first embodiment, before forming the lower resist film first layer 11 shown in FIG. 1A, an HMDS treatment for improving the adhesion between the stepped substrate and the lower resist film first layer is performed. In the second embodiment, the cost and the number of steps can be reduced by replacing the adsorption formation with the carbonyl compound.

As described above, according to the second embodiment, in the flattening of the lower resist film in the multi-layer resist, a carbonyl compound as a surface-active agent is adsorbed and formed on the stepped substrate by spin / coating to have a molecular weight of about 1000. Since a resist consisting of a low molecular weight organic polymer material is spin-coated to form a lower resist film, the lower resist film is flattened by heating it in a temperature region having thermal fluidity. Also, a good flattening lower layer resist film can be formed even on the edge portion of the substrate step portion, and the cost and the number of steps can be reduced.

Next, a third embodiment of the present invention will be described. As a third embodiment of the present invention, the heat treatment condition for flattening the lower resist film shown in the second embodiment is changed from a low temperature side to a high temperature side in a temperature range having fluidity, instead of a gentle temperature rising process. By repeating the heat treatment to the side in multiple stages, a good planarization lower layer resist film can be formed as in the second embodiment. The number of times of multi-step heat treatment is ideal as it is finer in the temperature range having fluidity, but when O-cresol novolac having a molecular weight of about 1000 is applied to the lower resist film, for example, 5 minutes at 170 ° C. → 1
Even with a three-step heat treatment of 90 ° C. for 2 minutes → 210 ° C. for 1 minute, a good planarization lower layer resist film can be formed almost as in the second embodiment. In that case, it is desirable that the heat treatment time be longer on the lower temperature side.

Further, by cooling the stepped substrate on which the lower resist film is formed during each of the multi-step heat treatments with a cleaning plate (for example, at 23 ° C. for about 1 minute), it is possible to control the heat treatment for planarization. Fluid reaction that occurs spontaneously,
Since the thermal cross-linking reaction that is occurring competitively can be reduced, the temperature and time that are dominant in the fluidity reaction can be widened,
It is possible to form a lower layer resist film with improved planarization.

As described above, according to the third embodiment, in flattening the lower resist film in the multilayer resist, the molecular weight of 100 is obtained in the same manner as in the first or second embodiment.
After forming a lower layer resist film by spin-coating a resist composed of about 0 organic polymer material, the lower layer resist film is subjected to a multi-step heat treatment from a low temperature to a high temperature side in a temperature range having thermal fluidity, and Since the flattening method of cooling the stepped substrate on which the lower resist film is formed during the stepwise heat treatment is used, as in the first and second embodiments, there are no pinholes, film unevenness, etc. It is possible to form a lower layer resist film having improved planarization as compared with the second embodiment.

Next, a fourth embodiment of the present invention will be described. As a fourth embodiment of the present invention, the heat treatment condition for flattening the lower resist film shown in the second and third embodiments is set to a gentle temperature rising process or a low temperature in a temperature range having fluidity. In place of repeating the heat treatment in multiple steps from the high temperature side to the high temperature side, a flattening lower layer resist which is good even by repeating a short flushing bake at a temperature having thermal fluidity using a lamp annealing furnace as shown in FIG. A film can be formed.

In FIG. 9, 51 is an arc lamp, 52 is a reflecting plate, 53 is a quartz plate, 54 is a metal chamber, 55 is a wafer, and 56 is a pyrometer. For example, when O-cresol novolac having a molecular weight of about 1000 is applied to the lower resist film, the bake temperature for flushing is 210 ° C., and the flushing interval is about 10 seconds. It is possible to form a flattening lower layer resist film which is almost as good as that of the embodiment.

As described above, according to the fourth embodiment, the flattening characteristic by the flushing bake described above largely depends on the bake temperature and the flushing interval.
-For a polymer material such as cresol novolak in which the thermal crosslinking reaction takes place in a competitive reaction in the heat fluidity temperature range (about 170 ° C to 220 ° C for O-cresol novolak having a molecular weight of about 1000), the heat flowability temperature range is used. It is better to make the flushing interval longer as the treatment is performed on the higher temperature side, and the same effect as cooling between each of the multi-step heat treatments of the third embodiment is obtained, and by reducing the thermal crosslinking reaction, It is possible to form a lower layer resist film with improved planarization.

Further, in the case of a polymer material having a large thermal fluidity such as O-cresol novolac, heat treatment from the resist surface such as baking in a lamp annealing furnace is more preferable than heat treatment from the substrate like hot plate baking. The adhesiveness to the substrate is better, and the lower resist film free from pinholes and film unevenness can be formed without applying the surface active agent of the substrate used in the second and third embodiments.

The present invention is not limited to the above embodiments, and various modifications can be made based on the spirit of the present invention, and these modifications are not excluded from the scope of the present invention.

[0040]

As described in detail above, according to the present invention, the following effects can be achieved. (1) According to the invention of claim 1 or 2, regardless of the type of the stepped substrate, it is possible to form a good flattened lower resist film without pinholes or film unevenness.

(2) According to the invention of claim 3 or 4, in addition to the effect of (1) above, a good planarizing lower layer resist film can be formed even on the edge portion of the substrate step portion,
It is possible to reduce costs and the number of processes. (3) According to the invention of claim 5, similarly to the above (1) and (2), it is possible to form a well-planarized lower layer resist film without pinholes, film unevenness and the like. it can.

(4) According to the invention described in claim 6, the flattening property by the flushing bake greatly depends on the baking temperature and the flushing interval. 1000
O-cresol novolac of about 170 ° C-220
In the case of a polymer material in which a thermal cross-linking reaction takes place in a competitive reaction at about (° C.), It is better to increase the flushing interval as the treatment is performed on the higher temperature side of the heat fluidity temperature region. It is possible to obtain the same effect as cooling between the respective cases, and it is possible to form a lower layer resist film with improved planarization by reducing the thermal crosslinking reaction.

Further, in the case of a polymer material having a large thermal fluidity such as O-cresol novolac, heat treatment from the resist surface such as baking in a lamp annealing furnace is more preferable than heat treatment from the substrate like hot plate baking. The adhesiveness to the substrate is better, and it is possible to form a lower layer resist film without pinholes or film unevenness without applying the surface active agent of the substrate used in (2) and (3) above. .

[Brief description of drawings]

FIG. 1 is a sectional view of a resist forming process showing a first embodiment of the present invention.

FIG. 2 is a flattening characteristic diagram of O-cresol novolac at each molecular weight during heat treatment at 200 ° C.

FIG. 3 is a resist flattening characteristic diagram with respect to a baking temperature.

FIG. 4 is a solvent resistance characteristic diagram of O-cresol novolac with respect to a baking temperature.

FIG. 5 is a solvent resistance characteristic diagram of O-cresol novolac with respect to molecular weight.

FIG. 6 is a cross-sectional view of a conventional resist.

FIG. 7 is a cross-sectional view of another conventional resist.

FIG. 8 is a sectional view of a resist forming process showing a second embodiment of the present invention.

FIG. 9 is a schematic explanatory diagram of a lamp annealing furnace.

[Explanation of symbols]

 10, 31 Stepped substrate 11 Lower resist film 1st layer 12 Lower resist film 2nd layer 13 Flattening lower resist film 2nd layer 20, 22, 41 Hot plate 21 Ultraviolet ray 32 Carbonyl compound 33 Lower resist film 34 Flattening lower resist film 51 Arc Lamp 52 Reflector 53 Quartz Plate 54 Metal Chamber 55 Wafer 56 Pyrometer

Claims (6)

[Claims] 1. A method of flattening a lower resist film in forming a resist pattern, comprising: (a) spin-coating a resist made of an organic polymer material having a relatively high molecular weight on a stepped substrate, followed by curing by heat treatment or ultraviolet irradiation. Forming a lower resist film first layer; and (b) spin-coating a lower molecular weight organic polymer material having a molecular weight of about 1000 on the lower resist film first layer to form a lower resist film second layer. Forming step, and (c) the lower resist film second
And a step of flattening the lower resist film second layer by heat-treating the layer at a temperature having thermal fluidity. 2. The resist flattening method according to claim 1, wherein the organic polymer material having a molecular weight of about 1000 is O-.
A method of planarizing a resist, which is cresol novolac and has a treatment temperature of 180 ° C. to 220 ° C. for thermal fluidization. 3. A flattening method for a lower resist film in forming a resist pattern, comprising the step of: (a) adsorbing and forming a carbonyl compound on a stepped substrate by spin coating.
(B) a step of spin-coating a resist composed of an organic polymer material having a molecular weight of about 1000 on the substrate on which the carbonyl compound has been adsorbed to form a lower resist film, and (c)
And a step of flattening the lower resist film by subjecting the lower resist film to a temperature rising process in a temperature region having thermal fluidity. 4. The resist planarization method according to claim 3, wherein the organic polymer material having a molecular weight of about 1000 is O-.
A method of planarizing a resist, which is cresol novolac and has a temperature rising region for heat flow of 150 ° C to 220 ° C. 5. A method of flattening a lower resist film in forming a resist pattern, comprising the step of: (a) adsorbing and forming a carbonyl compound on a stepped substrate by spin coating.
(B) a step of spin-coating a resist composed of an organic polymer material having a molecular weight of about 1000 on the substrate on which the carbonyl compound has been adsorbed to form a lower resist film, and (c)
A step of flattening the lower resist film by performing a multi-step heat treatment from a low temperature side to a high temperature side of the lower layer resist film in a temperature region having thermal fluidity, and (d) during each of the multi-step heat treatments. And a step of cooling the substrate on which the lower resist film is formed. 6. A method of flattening a lower resist film in forming a resist pattern, comprising the step of: (a) adsorbing and forming a carbonyl compound on a stepped substrate by spin coating.
(B) a step of spin-coating a resist composed of an organic polymer material having a molecular weight of about 1000 on the substrate on which the carbonyl compound has been adsorbed to form a lower resist film, and (c)
The heat treatment conditions for flattening the lower resist film are:
And a step of flattening the lower resist film by repeating flashing bake for a short time in a temperature region having thermal fluidity using a lamp annealing furnace.