JP2002189303A - Method of evaluating heat treating effect and method of evaluating resist baking apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of evaluating a heat treating effect by which the heat treating effect which a resist film receives actually through the whole of a baking step can be actualized and can be appropriately evaluated and to provide a method of evaluating a baking apparatus. SOLUTION: On a resist baking temperature-residual film rate curve, a region A in which the relation between the residual film rate and baking temperature of a resist film subjected to excessive film reduction treatment is represented by a steep and linear slope is present, and the dispersion in heat treating effect can be actualized as dispersion in residual film rate by using the region A as a working curve, and the heat treating effect which the resist film receives actually through the whole of a baking step can be appropriately evaluated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for realizing and evaluating a heat treatment effect actually applied to a resist film in a resist film baking step, and a method for evaluating a baking apparatus.

[0002]

2. Description of the Related Art For example, in order to manufacture an LSI or a photomask, a fine pattern processing by a photolithography method is necessary. In the process of performing the fine pattern processing, portions other than a portion to be etched are protected (masking). For this purpose, a resist pattern is formed. The resist pattern forming step includes a resist film forming step, a resist film baking (baking) step (including a step of cooling the resist film after baking), an exposing step, and a developing step.

[0003] Specifically, first, a resist is applied on a substrate to be processed to a desired film thickness by, for example, spin coating (spin coating). Next, in order to evaporate the solvent in the resist film, the substrate is fired using a firing device such as a hot-air circulating furnace (oven) or a hot plate (baking device) at a specified temperature and time according to the type of the resist. (Bake). After baking the resist film, the substrate to be treated with the resist film is cooled until it reaches room temperature, for example, by being left naturally in a clean atmosphere. Thereafter, the target substrate with the resist film is irradiated with an electromagnetic wave (for example, ultraviolet ray, X-ray, laser beam, or the like) in a predetermined wavelength range or a particle beam of a predetermined energy (for example, an electron beam or a charged particle) according to the type of the resist. (A line or the like) at a predetermined irradiation amount. After that, the exposed or unexposed portion of the resist is removed by a developing process to form a desired resist pattern.

[0004]

Incidentally, the measurement of the firing temperature is generally performed using a thermocouple. The measurement using a thermocouple is performed by directly attaching the thermocouple to the substrate surface or using a temperature measuring board with the thermocouple embedded. Or not), it is not possible to measure an accurate temperature (measurement accuracy, especially reproducibility is poor) due to the fact that the measured value differs depending on whether or not the compensation wire generates heat. Also, in measurement using a thermocouple, it is difficult to perform measurement by attaching a large number of thermocouples to a substrate, and thus the amount of information on the in-plane temperature distribution is small (at most 100 points or less). An infrared camera (thermoviewer) can measure the relative temperature difference but cannot measure the absolute temperature. Furthermore, in the case of a closed-type baking apparatus, the substrate cannot be exposed as on a hot plate, so that it cannot be measured with an infrared camera.

The biggest problem is that even if the in-plane distribution of the baking temperature can be measured accurately at any point in the entire baking process (for example, immediately after baking, during cooling), the resist film is not actually received. Heat treatment effect,
The effect of the heat treatment actually applied to the resist film throughout the baking process is unknown. For example, even if the sintering temperature immediately after sintering can be measured, the heat treatment effect actually received by the resist film depends on the cooling process or the like, for example, whether it is natural cooling or forced cooling, or the influence of the transport system to the cooling position, etc. Therefore, the effect of the heat treatment actually applied to the resist film throughout the baking process is unknown. Also,
For example, any point in the entire firing process (for example, immediately after firing)
However, even if it is found that there is a 1 ° C. in-plane temperature variation (non-uniformity), there is no idea what the actual resist performance will be. This is because the development step has a greater effect on pattern accuracy, and there is no difference after development. Similarly, even if the bake profiles E (dotted line) and F (solid line) (E is the periphery of the substrate and F is the center of the substrate) are precisely measured as shown in FIG. I have no idea how much the resist performance will vary.

[0006] After the baking treatment, it is only necessary to be able to evaluate the heat treatment effect by looking at some difference occurring in the resist itself according to the heat treatment effect actually received by the resist film. However, conventionally, such a difference could not be realized. However, the effect of the heat treatment actually applied to the resist film throughout the firing process could not be properly evaluated.

It is an object of the present invention to provide a method for evaluating a heat treatment effect, which can make the heat treatment effect actually received by a resist film throughout the entire baking process and which can be appropriately evaluated, and a method for evaluating a baking apparatus.

[0008]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the following has been found. A plurality of substrates having a resist film formed on the substrate are prepared, each of which is fired at a different firing temperature (fixing time and cooling conditions are fixed), and the resist film after firing is not subjected to an exposure treatment,
As shown in FIG. 1, the dissolution rate of the resist film, that is, the residual film ratio greatly changes with respect to the resist baking temperature, and the difference between the residual film ratios, that is, the The difference generated in the resist itself, not the difference measured by the meter, can be visualized. Here, since the baking time and the cooling conditions at each baking temperature are the same, the difference in baking temperature when baking at different baking temperatures appears largely as a difference in the heat treatment effect actually received by the resist film throughout the baking process. it is conceivable that. Therefore, the effect of the heat treatment actually applied to the resist film throughout the baking process can be visualized by the difference in the remaining film ratio. And FIG.
As shown in the figure, in the resist baking temperature-residual film ratio curve, the relationship between the remaining film ratio and the baking temperature of the resist film subjected to a remarkably excessive thinning treatment is a region A where a steep and linear relationship is observed between the two. It has been found that by using this region A as a calibration curve, the effect of the heat treatment actually applied to the resist film throughout the entire baking process can be realized and appropriately evaluated. That is, when the resist film baked at a certain temperature Y in the calibration curve is subjected to a remarkably excessive thinning treatment, the residual film ratio becomes X
However, in practice, the in-plane heat treatment effect varies, so that the in-plane residual film ratio varies, and the variation in the heat treatment effect can be quantified as the residual film ratio variation. In FIG. 1, a region B where the change in the residual film ratio is small with respect to a change in the firing temperature is a region where the influence of the in-plane temperature variation is small, and particularly a point C where the relationship between the two shows an extreme value.
In Japanese Patent Application Laid-Open No. Hei 7-264726 (Japanese Patent No. 303814), a method of forming a good resist pattern by adopting this temperature as an actual process firing temperature has been proposed.
No. 1)) is performed, but in this region B, the discrimination sensitivity is poor, and the variation in the heat treatment effect cannot be manifested, so that it is not suitable as a calibration curve. As described above, the present invention does not evaluate the heat treatment effect in a temperature range suitable as the actual process firing temperature. In contrast, as in the present invention,
Temperature range A in which the residual film ratio changes greatly with the change in firing temperature
By using the method, the sensitivity of discriminating the heat treatment effect is increased, and the variation in the heat treatment effect actually received by the resist film can be made obvious. Therefore, it becomes easy to grasp the heating performance of the firing device and the substance of the entire firing process. Then, it is possible to easily evaluate the baking apparatus which is one of the resist pattern forming conditions, select and determine the optimum baking apparatus based on the evaluation result, and use the optimum baking apparatus to bake the resist film. By doing so, it is possible to form a resist pattern with good pattern dimensional accuracy and pattern shape accuracy in-plane uniformity and the like.

The present invention has the following configuration. (Structure 1) A plurality of substrates each having a resist film formed on the substrate are prepared and fired at different firing temperatures (fixing time and cooling conditions are fixed). Dissolve each of the resist films baked in step under predetermined processing conditions where the resist film partially dissolves (thin film reduction)
By performing the treatment, a resist baking temperature-residual film rate curve is obtained,
A step of intentionally selecting a predetermined region in which the residual film ratio changes in a predetermined relationship with respect to a change in the firing temperature with respect to a change in the baking temperature as a calibration curve in advance, and newly adding a substrate having the same resist film as described above on the substrate. Preparing and firing the substrate at a temperature Y at which the residual film rate becomes X in the temperature range of the calibration curve (the firing time and cooling conditions are the same as those described above); A step of subjecting the resist film to a dissolving (thinning) process under the same processing conditions as above in which the resist film partially dissolves;
A method for evaluating a heat treatment effect, comprising: a step of measuring the thickness of a resist film after a dissolution treatment; and evaluating the heat treatment effect by using the thickness of the resist film after the dissolution treatment.

(Structure 2) A step of obtaining a residual film ratio x from a measured value of the film thickness before and after the dissolving (thinning) process for the resist film baked at the temperature Y, and using the residual film ratio x The method for evaluating a heat treatment effect according to Configuration 1, wherein the heat treatment effect is evaluated.

(Configuration 3) The residual film ratio x is applied to the firing temperature-remaining film ratio curve (calibration curve) to determine a corresponding firing temperature y, and the heat treatment effect is evaluated using the firing temperature y. 3. The method for evaluating a heat treatment effect according to Configuration 2, wherein:

(Structure 4) The method according to any one of Structures 1 to 3, wherein the evaluation is performed using a resist that can be fired at a high temperature.

(Structure 5) The method according to any one of structures 1 to 4, wherein the predetermined temperature range is set to a temperature lower than an optimum firing temperature in the process of the resist used for the evaluation. .

(Structure 6) An evaluation method for a firing apparatus using the heat treatment effect evaluation method according to any one of Structures 1 to 5.

(Structure 7) A resist pattern characterized by comprising a step of selecting and determining an optimum firing device by using the firing device evaluation method described in Structure 6, and firing the resist film using the firing device. Forming method.

[0016]

According to the constitution 1, the resist film fired at the temperature Y at which the residual film ratio becomes X in the temperature range of the calibration curve is subjected to a dissolving (thinning) process under a processing condition in which the resist film partially dissolves. By measuring the thickness of the resist film after the dissolution treatment, if the resist film baked at a certain temperature Y in the calibration curve is significantly reduced excessively, the residual film ratio becomes X (reduced film thickness). Although the amount should be X '), in practice, there is variation in the in-plane heat treatment effect, resulting in variation in the in-plane film reduction amount, and this heat reduction effect on the substrate as this reduction in film thickness, that is, variation in film thickness. Variations in the effects can be clarified and quantified.
In the configuration 1, the variation in the film thickness due to the variation in the heat treatment effect is larger than the variation in the coating thickness of the resist (the variation in the coating thickness of the resist is negligible). The heat treatment effect can be evaluated using the thickness of the resist film after the treatment. In the configuration 1, for example,
The uniformity of the heat treatment effect can be evaluated using the uniformity of the remaining thickness of the resist film after the dissolution treatment. In this case, the film thickness can be measured precisely at many points in the plane (for example, 3000 points in the measurement area) in units of 1 angstrom, so the number of measurement points is limited (at most 100 points or less), and More accurate information can be obtained as compared to measurement using a thermocouple or the like having poor measurement reproducibility. In the configuration 1, the predetermined dissolution processing conditions under which the resist film partially dissolves include the dissolution processing conditions (development conditions when forming a resist pattern, which are not usually used because the pattern accuracy and shape are deteriorated and the amount of film reduction is large). (Dissolution treatment conditions in which the residual film ratio becomes smaller than the appropriate residual film ratio). For example, in a normal developing process, a weak dissolving process condition in which a residual film ratio becomes 90% (a film reduction amount is 10%) in order to maintain good pattern accuracy and shape, whereas in the present invention, for example, a normal dissolving process is not used. It is preferable to carry out the treatment under strong dissolution treatment conditions in which the residual film ratio is 40 to 50% (the film reduction amount is 50 to 60%) and the film is extremely excessively reduced. In the configuration 1, the resist baking temperature-
The predetermined region in the remaining film ratio curve where the remaining film ratio changes in a predetermined relationship with respect to the change in the firing temperature excludes a region where the change in the remaining film ratio is small relative to the firing temperature (for example, region B in FIG. 1). Area. The predetermined region is preferably a temperature region where the sensitivity of the heat treatment effect is high in the firing temperature-residual film ratio curve. Specifically, a temperature region where the change in the residual film ratio is large relative to the change in the firing temperature is preferable. A temperature region in which the change in the residual film ratio is large and changes linearly with the change in temperature is more preferable. The baking temperature-residual film ratio curve changes depending on the resist material, for example, as indicated by the dotted line in FIG. Therefore, it is possible to evaluate the heat treatment effect by selecting a resist material in which the residual film ratio changes greatly and linearly around the actual firing temperature for the resist.
Of course, a resist material having a large change in the remaining film ratio and changing linearly near the actual firing temperature region may be selected to evaluate the heat treatment effect. In Configuration 1,
The “calcination temperature” in the calcination temperature-residual film ratio curve (including the calibration curve) may be either the set temperature of the calcination device or the actual measurement temperature. In addition, when creating a baking temperature-residual film rate curve (including a calibration curve), it is preferable to take the average of a large number of points in the plane, so that the influence of the temperature unevenness of the heating device and the unevenness of the film reducing treatment can be ignored. .

According to the second aspect, the effect of the heat treatment can be evaluated by using the remaining film ratio x obtained from the measured value of the film thickness before and after dissolving (thinning) the resist after baking at the temperature Y. As described above, by using the residual film ratio x, the influence of the variation in the coating thickness of the resist can be completely eliminated, so that the heat treatment effect can be more accurately evaluated as compared with the configuration 1. In the configuration 2, the residual film ratio x is obtained from the measured values of the film thickness before and after the dissolution (thinning) process, and the film thickness is measured at a number of points on the surface in units of 1 angstrom (for example, 300 in the measurement area).
(0 point) can be precisely measured, so that more accurate and more information can be obtained as compared with measurement using a thermocouple or the like.
In the configuration 2, for example, the uniformity of the heat treatment effect can be evaluated from the uniformity of the remaining film ratio x. In this case, as the difference in the residual film ratio, that is, the difference generated in the resist itself, the effect of the heat treatment actually applied to the resist film can be made obvious throughout the baking process, so that more direct information can be obtained as compared with measurement using a thermocouple or the like. . Further, the variation in the heat treatment effect (variation in the firing process) can be quantified as the variation in the remaining film ratio. In the configuration 2, for example, the uniformity of the heat treatment effect can be evaluated from the difference between the remaining film ratio x and the remaining film ratio X.

According to the configuration 3, the uniformity of the heat treatment effect can be evaluated as a difference in the firing temperature y by obtaining the corresponding firing temperature y from the remaining film ratio x via the calibration curve.

According to the fourth aspect, the evaluation is performed using a resist that can be fired at a high temperature. As the firing temperature increases, the temperature variation of the firing apparatus increases, and the uniformity of the firing (baking) is substantially linear. This is preferable because the deterioration is made (the habit of the firing device is emphasized), and the evaluation of the firing device becomes easy. Here, a resist that can be fired at a high temperature is an optimum firing temperature of 90 for many resist processes.
A resist having an optimum baking temperature in the process higher than that of -150 ° C, for example, 180-250 ° C.

According to the fifth aspect, the predetermined temperature range is defined by:
It is preferable to set the temperature lower than the optimum firing temperature in the process of the resist used for the evaluation (for example, use the region A in FIG. 1 as a calibration curve) because the evaluation of the heat treatment effect becomes highly accurate. In general, the resist has a relationship between the resist baking temperature shown in FIG.
The inclination of the calibration curve tends to be smaller in the temperature region A lower than the point C where the in-plane temperature variation is smallest than in the temperature region D higher than the point C, and the error is smaller than that in the region D where the inclination is large. It is because it becomes less. As the firing temperature increases, the uniformity of firing is considered to decrease almost linearly. Therefore, if the uniformity on the high temperature side is good, the uniformity is good even below that temperature (the firing temperature in the actual process). Is preferable because it can be estimated.

According to the sixth aspect, the baking apparatus is evaluated by using the heat treatment effect evaluation method described in the first to fifth aspects. ) Can be quantitatively determined, and the determination of the suitability of the device can be made with high identification sensitivity. In addition, it becomes possible to evaluate the reproducibility of firing by the firing apparatus and the stability of the firing apparatus.
Further, it is easy to grasp the substance of the entire firing process. From these facts, it is possible to optimize the design of the baking apparatus and improve the substrate transfer system.

According to the configuration 7, by using the evaluation method of the baking apparatus described in the configuration 6, an optimum baking apparatus having high uniformity can be selected and used, and the baking apparatus is used to bake the resist film. By doing so, it is possible to contribute to improvement in pattern accuracy, pattern shape, and the like.

[0023]

EXAMPLE 1 Preparation of Calibration Curve First, a photomask formed by forming a chromium light-shielding film on a quartz substrate 0.25 inch thick, 6 inch × 6 inch square and appropriately polished. A plurality of production substrates (blanks) are prepared, each substrate is placed on a turntable one by one, and a resist (ZEP7000: manufactured by Zeon Corporation) solution that can be fired at a high temperature is dropped from a discharge nozzle, and spin coating is performed. Thus, the resist was applied such that the film thickness after firing and cooling was about 4000 Å.

Next, the firing temperature of the resist was changed every 10 ° C. from 100 ° C. to 250 ° C., and each substrate was fired for one firing time using an apparatus (hot plate size) described later.
After 2.5 minutes, it was baked, and was automatically transported and rapidly cooled uniformly on a cooling plate to eliminate the influence of the cooling step.

Next, for each of the fired substrates, a spectral interference type film thickness measuring apparatus (AFT6100, manufactured by Nanometrics) employing a method of measuring an optical film thickness from a spectral reflection curve.
Was used to measure the resist film thickness (841 points (29 points × 29 points) in a 140 mm square area at the center of the substrate), and the average value of the resist film thickness was calculated.

Next, each of the fired substrates is dissolved in diglyme of an organic solvent by an immersion method for 120 seconds (remarkably excessively reduced film thickness).
After that, the resultant was subjected to intermediate rinsing with MIBK (methyl isobutyl ketone) as an organic solvent for 30 seconds, rinsed with IPA for 5 seconds, and spin-dried. Thereafter, in order to increase the accuracy of the film thickness measurement, the resist residue adhering to the surface was physically removed by an underwater hand scrub and dried naturally.

Next, the thickness of each resist film that has been sufficiently dried after the film-thinning treatment is measured in the same manner as described above, and the average value of the remaining resist thickness after the film-thinning treatment is calculated. did.

Next, the residual film ratio was calculated for each firing temperature from the difference between the average values of the resist film thickness before and after the film-thinning treatment obtained above, and a firing temperature-remaining film ratio curve was obtained (FIG. 1). Then, in the firing temperature-residual film ratio curve, the temperature region (13) where the residual film ratio linearly largely changes with respect to the change in the firing temperature.
(0 ° C to 190 ° C) was intentionally selected and used as a calibration curve. The optimum firing temperature in the process of ZEP7000 is 22
0 ° C.

Evaluation of Firing Apparatus First, a plurality of substrates having the same resist film as above prepared under the same conditions as above were prepared. Specifically, a thickness of 0.25
Prepare a plurality of photomask working substrates (blanks) in which a chromium light-shielding film is formed on a quartz substrate having an appropriate size of 6 inches x 6 inches and having a surface polished,
Each substrate is placed on a turntable one by one, and a resist (ZEP7000: manufactured by Zeon Corporation) solution that can be baked at a high temperature is dropped from a discharge nozzle. The resist was applied so as to have a thickness of about 4000 angstroms.

Next, the sintering was performed at the respective sintering apparatuses and the sintering temperatures shown in Table 1 and the sintering time was set to 12.5 minutes, the same as above. FIG. 4A shows an example of a hot plate, FIG. 4B shows an example of an upper and lower hot plate, and FIG. In FIG. 4, reference numeral 1 denotes a substrate with a resist film, 2 denotes a hot plate, and 3 denotes a hermetic seal. In Table 1, "Hot plate small" is 195m
m square size (heater capacity 0.6 kW), "hot plate large" is 230 mm square size (heater capacity 1.
8 kW), the upper and lower hot plates are 230 m each
A m-sized one (heater capacity: 1.8 kW) was used. The "sealed type A" is a device of a type in which a heater is provided at the lower part of the substrate and the periphery is sealed, and the "sealed type B" is a device of a type in which a heater is provided at the lower part of the substrate and a reflector is provided above the substrate to seal the periphery. It is. After firing, it was automatically conveyed and rapidly cooled on a cooling plate.

Next, each of the fired substrates was subjected to a film reduction treatment under the same conditions as described above. Specifically, each of the fired substrates is subjected to a dissolving (remarkably excessively thinning) treatment by a dip method for 120 seconds in ZEP-D, which is a diluent, and then to an organic solvent MIBK (methyl isobutyl ketone) for 30 seconds. Intermediate rinse, IP
Rinse with A for 5 seconds, spin dry and let stand.

Next, the film thickness after the film-thinning treatment was measured, and the average value, standard deviation σ, and range value of the remaining resist thickness after the film-thinning treatment were calculated. Table 1 shows these results, and FIGS. 2 and 3 show bird's-eye views of the in-plane film thickness distribution after the film-thinning treatment.

The film thickness after the film-thinning treatment was measured using the same spectral interference-type film-thickness measuring apparatus (manufactured by Nanometrics: AF) for each resist film sufficiently dried after the film-thinning treatment.
T6100), the resist film thickness was measured (841 points (29 points × 29 points) in the measurement area shown in Table 1). In Table 1, the range value indicates the difference between the maximum value and the minimum value of the film thickness after the film-thinning treatment, and the sigma value indicates the magnitude of the film thickness variation.
Further, the difference in the firing temperature was determined in consideration of the difference in the firing effect (the closed system has a higher firing effect than the open system). The variation in the coating thickness of the resist is less than 50 angstroms, which is negligible because it is smaller than the film thickness reduction. Regarding the measurement area, the use area of the 6-inch substrate is 140 mm.

[0034]

[Table 1]

From Table 1, it is found that the amount of film reduction is about 50 to 55% with respect to the resist coating film thickness (4000 angstroms).
Regarding the hot plate, the larger the plate volume (heater capacity), the smaller the in-plane variation (sigma value, range value) of the film reduction amount, and the more the plates are arranged vertically, the smaller the film reduction amount. In-plane variation (sigma value,
(Range value) becomes smaller. In addition, it can be seen that in the closed type apparatus, the variation (sigma value, range value) in the substrate surface of the film reduction amount is smaller. Further, it can be seen that even in the case of the closed type apparatus, the variation (sigma value, range value) in the substrate surface of the film reduction amount differs depending on the maker or the like. Further, it can be seen from the graph of FIG. 3 that in the closed type apparatus, the amount of film reduction around the substrate is large, and a significant difference occurs in the heat treatment effect around the substrate. Also, in the closed type A apparatus, traces of the jig of the transport system appear. These facts were not understood by the conventional evaluation method based on temperature measurement.
The results of Table 1 and FIGS. 2 and 3 were compared and examined, and the closed type B was determined as the optimum firing apparatus.

(Embodiment 2) In the "Evaluation of firing apparatus" step of Embodiment 1, the film thickness before the film-thinning treatment was measured by the same method as described above, and the measured value of the film thickness after the film-thinning treatment was compared with the measured value. From the difference, the residual film ratio was calculated, and the same evaluation was performed. As a result, the influence of the variation in the coating film thickness was eliminated, and the evaluation accuracy was further improved.

Comparative Example 1 Using ZEP7000, 21
0 ° C, 220 ° C (optimal firing temperature in process), 230
It baked using each apparatus at ℃, and performed the same evaluation. As a result, the discrimination sensitivity is poor, and the sintering temperature range in which the variation in the heat treatment effect cannot be evident. And it was not possible to judge the suitability of the device.

(Example 3, Comparative Example 2) Using ZEP7000, firing at 220 ° C. (optimal firing temperature in the process) using each apparatus, performing normal development and etching, and performing pattern dimension accuracy and pattern Evaluation of shape accuracy was performed. As a result, the accuracy of the closed mold B was the best. Similarly, the same evaluation was performed using a resist having an optimum firing temperature of 150 ° C. in the process, and as a result, the same tendency was recognized.

Although the present invention has been described with reference to the preferred embodiments, the present invention is not limited to the above embodiments. For example, the resist material, the baking temperature range used as the calibration curve, the conditions for the film reduction, and the like are not limited to those in the above-described embodiment. The substrate material is not particularly limited, and the heat treatment effect can be evaluated even with a silicon wafer or another material.

[0040]

As described above, according to the present invention,
It has the following effects. (1) The heat treatment effect actually received by the resist film throughout the baking process can be clarified and quantified, and the heat treatment effect can be appropriately evaluated. (2) Since the film thickness can be measured precisely in units of 1 angstrom, the accuracy of information is high (resolution and discrimination sensitivity are high). (3) Since the film thickness can be measured precisely at many points in the plane, the information amount is large (for example, 30 points in the measurement area).
00 point), the effect of the heat treatment at any point in the plane can be easily measured and observed. (4) Not affected by other process factors. (5) The heating characteristics of the baking apparatus (habit of the apparatus = tendency and non-uniformity of baking) can be quantitatively understood, and the applicability of the apparatus can be determined with high identification sensitivity. In addition, it becomes possible to evaluate the reproducibility of firing by the firing apparatus and the stability of the firing apparatus. Further, it is easy to grasp the substance of the entire firing process. From these facts, it is possible to optimize the design of the baking apparatus and improve the substrate transfer system. (6) By selecting and using a highly uniform firing apparatus,
It can contribute to improvement of pattern accuracy and pattern shape.

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between a resist baking temperature and a remaining film ratio after a predetermined film-thinning process.

FIG. 2 is a diagram showing a measurement result of a remaining film thickness after a predetermined film-thinning process.

FIG. 3 is a diagram showing a measurement result of a remaining film thickness after a predetermined film-thinning treatment.

FIG. 4 is a front view for explaining a baking apparatus.

FIG. 5 is a diagram for explaining a firing profile.

Claims (7)

[Claims] A plurality of substrates each having a resist film formed on the substrate are prepared, and each of the substrates has a different firing temperature (firing time,
Cooling conditions are fixed), and each of the resist films fired at each firing temperature is subjected to a dissolving (thinning) process under predetermined processing conditions in which the resist film partially dissolves without subjecting them to exposure processing. Obtaining a resist baking temperature-residual film rate curve, and intentionally selecting a predetermined region in which the remaining film rate changes in a predetermined relation with respect to a change in the baking temperature as a calibration curve in advance on the substrate; A substrate on which the same resist film as above was formed was newly prepared, and this substrate was fired at a temperature Y at which the residual film ratio was X in the temperature range of the calibration curve (the firing time and cooling conditions were the same as above). A) dissolving (thinning) the resist film after baking at the temperature Y under the same processing conditions as above in which the resist film partially dissolves; The step of measuring and after the dissolution treatment A method for evaluating a heat treatment effect, wherein the heat treatment effect is evaluated using the thickness of a resist film. 2. A step of obtaining a residual film ratio x from a measured value of a film thickness before and after a dissolution (thinning) process of the resist film after baking at the temperature Y, and a heat treatment effect using the residual film ratio x. The method for evaluating a heat treatment effect according to claim 1, wherein: 3. Applying the remaining film rate x to the firing temperature-residual film rate curve (calibration curve) to obtain a corresponding firing temperature y, and evaluating the heat treatment effect using the firing temperature y. The method for evaluating the effect of heat treatment according to claim 2. 4. The method according to claim 1, wherein the evaluation is performed using a resist that can be fired at a high temperature. 5. The method for evaluating a heat treatment effect according to claim 1, wherein the predetermined temperature region is set at a temperature lower than an optimum baking temperature in a process of a resist used for evaluation. 6. A method for evaluating a baking apparatus using the method for evaluating a heat treatment effect according to claim 1. 7. A resist pattern forming method comprising the steps of selecting and determining an optimum baking apparatus using the baking apparatus evaluation method according to claim 6, and baking a resist film using the baking apparatus. Method.