JPH11194506A - Pattern forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a resist film having a uniform and very precise size distribution. SOLUTION: The subject method is so composed that a pattern exposure is performed on a resist film formed on a mask (3), and subsequently baking process and a development process are performed (7) to thereby form a resist pattern. In this case, the baking process after the exposure is composed of primary and secondary processes ((4), (6)), and a process, in which a size distribution of the resist film is measured (5), is inserted between the primary and the secondary processes. The primary process is performed uniformly on the whole resist film, and the secondary process is performed partially to correct and uniform unevenness of the surface based on the measured size distribution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pattern forming method applied to a lithography technique for forming a resist pattern and processing a substrate.

[0002]

2. Description of the Related Art In recent years, fine processing techniques represented by semiconductor integrated circuit manufacturing have realized the formation of patterns of 0.5 μm or less. For further miniaturization in the future, formation of finer resist patterns and associated processing techniques are required. In the lithography technology, high sensitivity resists represented by chemically amplified resists are being used for the purpose of improving productivity and the like.

However, increasing the sensitivity of the resist, on the other hand, indicates instability in the resist process or lack of margin for processing conditions. For example, a chemically amplified resist has higher sensitivity than a general resist, but has a large dimensional change with respect to a baking temperature and a baking time.
High-precision baking is essential. In addition, dimensional changes occur depending on the time from exposure to baking,
It has been reported that a dimensional distribution depending on the time elapsed from exposure occurs in a substrate.

For example, in a sequential exposure method such as electron beam exposure, not only the exposure time is long but also the exposure speed can be changed depending on the pattern density, so that the dimensional fluctuation factor is more complicated. Further, depending on the time from the end of the exposure to the post-exposure bake (PEB), the influence of the atmosphere and the deactivation of the generated acid catalyst occur.

A reticle used for light exposure such as a stepper is also manufactured by applying lithography technology. However, in a reticle manufacturing process, high-density data requiring an exposure time exceeding one hour is required even when a high-sensitivity resist is used. There is also exposure. This dimensional variation depending on the length of the exposure time is not acceptable for higher precision in the future. In particular, in the case of a reticle, the outer shape of the reticle is rectangular, the thickness is several mm, and it is made of glass such as quartz, which has extremely poor thermal conductivity. It shows more complicated thermal characteristics as compared with the above, making it more difficult to bake a uniform resist film.

As a result, it is difficult to apply a highly sensitive resist, particularly a chemically amplified resist. Further, in the case of a reticle, since each reticle is manufactured based on different pattern data, it is difficult to control a finished dimension even by using the same process.

[0007]

As described above, in the conventional pattern forming method, the dimension changes depending on the length of time from exposure to baking, and the dimensional distribution depends on the elapsed time from exposure. Are generated in the substrate, but this dimensional non-uniformity is not acceptable for higher precision in the future.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a pattern forming method capable of forming a resist pattern having a uniform and highly accurate dimensional distribution. is there.

[0009]

According to a first aspect of the present invention, there is provided a pattern forming method comprising: performing a pattern exposure on a resist film formed on a substrate to be processed; and performing a baking and developing process after the pattern exposure. In the pattern forming method for forming a resist pattern, the post-exposure baking includes first and second steps, and the first step is performed uniformly on the entire resist film, and the second step is performed in the first step. The method is characterized in that in-plane non-uniformity of the size distribution obtained in the process is partially corrected so as to be uniform.

According to a second aspect of the present invention, there is provided a pattern forming method, comprising: performing a pattern exposure on a resist film formed on a substrate to be processed; and uniformly baking the entire resist film after the pattern exposure. A first baking step of performing, and a step of measuring the dimensional distribution of the resist film after the first baking, to correct the in-plane non-uniformity based on the measured dimensional distribution so as to be uniform. A second baking step of partially baking and a step of developing the resist film after the second baking are provided.

Preferred embodiments of the present invention are as follows. (1) The step of measuring the in-plane uniformity of the resist film is a step of measuring a latent image of the resist pattern. (2) The baking performed partially in the second baking step is to increase the baking time in a region having a large resist pattern size for a positive resist,
The baking time is shortened in a small area. In the case of a negative resist, the baking time is lengthened in a region having a small resist pattern size, and the baking time is shortened in a region having a small size.

According to a third aspect of the present invention, there is provided a pattern forming method, comprising: performing a pattern exposure on a resist film formed on a substrate to be processed; and uniformly baking the entire resist film after the pattern exposure. A first baking step to perform, and a second baking to partially correct the in-plane non-uniformity based on the measurement result of the in-plane non-uniformity of the dimension distribution measured in advance so as to be uniform. A baking step and a step of developing the resist film after the second baking are provided.

According to a fourth aspect of the present invention, in the pattern forming method, the resist is a chemically amplified resist. The pattern forming method according to claim 5 of the present invention is characterized in that the second baking is to blow the temperature-controlled gas such that the blown area achieves in-plane uniformity. I do.

Preferred embodiments of the present invention are as follows. (1) The temperature controlled gas is blown by changing the blowing time for each blown area so that the blown area achieves in-plane uniformity. (2) The temperature-controlled gas is blown by changing the gas temperature for each blown area so that the blown area achieves in-plane uniformity. (Operation) In the present invention, pattern exposure is performed on a resist film formed on a substrate to be processed, and the baking process after the pattern exposure is performed in two stages, a first baking process and a second baking process. Here, the first baking process is performed uniformly over the entire surface of the resist film, and the first baking process is partially performed so as to correct and uniform the in-plane non-uniformity of the dimensional distribution obtained by the first baking process. A second baking process is performed.

As described above, the post-exposure bake process is divided into two times, and after the first bake process is performed uniformly over the entire surface of the resist film, the in-plane non-uniformity caused by the bake process is corrected. By performing the second baking process partially, in-plane uniformity of the dimensions of the resist film can be obtained, and a high-precision lithography process can be realized.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is a flowchart showing a pattern forming step by a pattern forming method according to a first embodiment of the present invention. An example in which this pattern forming method is applied to a mask manufacturing process will be described with reference to this flowchart. 2 to 4 are views for explaining a pattern forming method according to the present embodiment. FIG. 2 is a cross-sectional view of a baking apparatus used for a first baking process, and FIG. FIG. 4 is a view showing a size distribution in the mask after the processing, and FIG. 4 is a cross-sectional view of a baking apparatus used for the second baking processing.

First, a positive resist made by Nippon Synthetic Rubber Co., Ltd. is applied to a 6 inch square, 0.25 inch thick chromium mask blank called 6025 standard made by HOYA to a thickness of 0.5 μm (1). . After this resist is applied, baking (prebaking) is performed at 90 ° C. for 10 minutes in order to remove the solvent and moisture of the resist film applied to the mask and to make the film dense (2).

Next, pattern exposure is performed on an area of 130 mm square with an exposure amount of 10 μC / cm ² using an electron beam lithography apparatus with an acceleration voltage of 50 KeV (3). The exposure pattern is a device pattern having a minimum line width of 0.8 μm on the mask, and 46 evaluation patterns for measuring the dimensions of the mask are arranged. The exposure apparatus is an apparatus employing a VSB (variable shaped beam) method, and performs multiple writing in which exposure at 2.5 μC / cm ² is performed four times. After the pattern exposure, the mask is held in a vacuum for 20 minutes, then taken out into the air and left for 30 minutes.

Next, as shown in FIG. 2, a first baking process (PEB) for 15 minutes while holding the mask 13 on a hot plate 12 held at 90 ° C. through a 0.2 mm spacer 11 is performed. Perform (4). The hot plate 12 is applied to the entire surface of the mask 13 so that the entire surface of the mask 13 is baked uniformly. Immediately after the first baking treatment, the plate is placed on a plate kept at 23 ° C. and left for 20 minutes. A discolored pattern is formed on the resist film, and a latent image is formed in the resist film. The dissolution rate in the developer changes depending on not only the exposure but also the baking conditions after the exposure. Therefore, by changing the baking conditions in the substrate, the dimensional distribution in the substrate can be changed.

The mask 13 that has been subjected to the pattern exposure and has been subjected to the uniform baking process is placed on the stage of an optical microscope, and the size of the latent image of the evaluation pattern is compared (5). The resist film that has been subjected to the first baking process shows an optical reaction in association with its photosensitivity and thermal reaction. By measuring the latent image showing the optical reaction, the expected resist pattern size after development is determined.

In this embodiment, the dimensions of the mask actually subjected to the above processing were measured. As a result, the dimension distribution shown in FIG. 3 was obtained. In FIG. 3, the displayed value represents the dimension value of the space pattern of the resist. This dimension measurement result is 1/3 of the target dimension of 0.8 μm.
In the region of 25 nm or more. The size distribution almost coincided with the exposure order. That is, as the drawing progresses from the upper left to the lower right in FIG. 3, which is the starting point of the exposure, the time from the exposure becomes shorter, and the dimension value of the space pattern tends to increase. The post-exposure bake treatment is to reduce the line pattern of the resist by the treatment, that is, to reduce the dimension value of the space pattern. Therefore, it has been found that additional baking is particularly necessary near the start point of the exposure, and the necessity of the additional baking is reduced as the exposure end point is approached.

Based on the value of the dimensional non-uniformity obtained in this way, data between the measurement points is complemented and extrapolated to create data.
Correction data with a 5 mm mesh is created over the entire area of 150 mm square.

Next, in order to correct the dimensional non-uniformity caused by the first baking, a second baking process is performed based on the correction data created above (6). Unlike the first baking process, the second baking process is partially performed on the resist film surface. Specifically, as shown in FIG.
5, the mask 13 is fixed with the resist film surface facing upward. Then, air at 90 ° C. is blown toward the resist film surface in a spot form from a blower tube 17 provided above the resist film surface. The diameter of the blow hole of the blower tube 17 is 15 mmφ
The x, y stage 14 is continuously moved in the x direction, that is, the vertical direction in FIG. 3, and performs a step movement of 10 mm in the y direction, that is, the left and right direction in FIG.

The blowing time at each point is such that the dimensional difference is 5 nm.
At a certain point, for example, the stage is adjusted to move 5 mm in 15 seconds, and at a point where the dimensional difference is 10 nm, the stage is adjusted to move 5 mm in 30 seconds. To slow down the stage movement. In the actual mask processing in the present embodiment, the stage movement starts from the outermost periphery of the mask 13,
Move continuously in the x direction from the starting point at the upper left in FIG.
Further, the entire surface was scanned by a step movement of 10 mm in the y direction. Then, in order to perform high-precision baking by averaging the in-plane temperature history by this full-surface scanning, the device was turned back to the starting point, and the same full-surface scanning was repeated.

As can be seen from the measurement results of the dimension distribution shown in FIG. 3, the dimension value of the space pattern is small in the upper left area, ie, near the start point of exposure, and the difference from the desired dimension value is large, so that the air blowing time Was longer, that is, the duration of the stage was longer. The blowing time was shortened in accordance with the scanning order of the x and y stages 14, that is, the stay time of the stage was shortened.

As described above, after the dimension measurement of the resist pattern, by performing the second baking process additionally for each region, a partial dimensional change accompanying the baking can be generated. In other words, when the dimension of the latent image is measured and an area that does not reach the target dimension is predicted, the dimension can be set to the target value by performing additional baking on the area. In consideration of the second baking process, it is desirable to set the baking conditions so that the finished size of the first baking is slightly under the target value.

If the in-plane uniformity has already been obtained by the first baking by the measurement of the latent image, the predetermined development time is set such that the dimension reaches the target value without performing the second baking. , The target dimensional uniformity can be obtained.

As described above, the dimensional non-uniformity that cannot be achieved even when the resist is uniformly processed by the first baking process can be controlled by partially increasing or decreasing the baking amount. That is, by partially baking the resist film as the second baking process, the dimensional non-uniformity caused by the first baking process can be corrected.

Next, the latent images of the above evaluation patterns are compared again, and it can be confirmed that the predicted finished dimensions can be obtained within the target dimensional variation by developing for 75 seconds. Then, the mask was set on a spray developing device, and a developer (AD-10 manufactured by Tama Chemical) whose temperature was controlled at 23 ° C. from a full cone nozzle.
Is sprayed and rotated at 100 rpm for development for 75 seconds (7), and immediately rinsed with ultrapure water. Next, after baking (post-baking) at 100 ° C. for 20 minutes (8), plasma descum treatment using wet air is performed by a parallel plate type dry etching apparatus (9). Etching is performed at 75 W for 5 minutes, and this treatment reduces the resist film thickness by about 0.05 μm.

Next, the light-shielding film containing chromium as a main component is etched using a mixed gas of chlorine and oxygen (1).
0). Etching with a thickness of about 0.1 μm is performed for 20 minutes. From the monitor of the reflected wave intensity of RF (Radio Frequency), it is just + 10% etching.

After completion of the etching, the resist is removed, and the dimension of a space pattern whose design data is 0.8 μm is measured with a confocal microscope. In the dimension measurement, the same point is measured 16 times to confirm the reliability of the data. In the actual mask processing in the present embodiment, the dimensions of the evaluation pattern at 46 locations are 0.812 μm on average, the variation is 21 nm (3σ), and the difference between the maximum value and the minimum value is 31 nm.

Further, the mask 13 having the dimensional non-uniformity corrected
In order to confirm the transfer characteristics, a pellicle is adhered to the manufactured mask 13 and then transferred by an excimer laser exposure apparatus manufactured by Nikon Corporation. The coating type antireflection film 55n is applied to the base of the pattern formation process of the device wiring process on the 8-inch wafer.
m, and then a 50-cm chemically amplified resist is used.
The film is applied to a thickness of 0 nm and a normal exposure process is performed. The dimensions of the resist pattern obtained after development are measured using a length measuring SEM (Scannin
g Electron Microscope). In the actual mask processing, an average value of 0.183 μm and a variation of 21.2 nm (3σ) were obtained in a portion where the design dimension was 0.2 μm in the line and 0.18 μm in the space. This value exceeded 27 nm in the conventional mask, and it was confirmed that high-precision exposure was possible due to in-plane uniformity. In addition, a large distribution of the kind considered to be caused by the mask was not recognized in the shot of the exposure apparatus.

As described above, the baking process after pattern exposure is divided into the first baking and the second baking. The first baking process is performed uniformly on the entire resist surface, and the second baking is performed on the resist film surface. By partially correcting the in-plane non-uniformity based on the measurement result of the dimensional distribution, the in-plane uniformity of the resist film can be obtained with high accuracy. In addition, since the size distribution can be observed by measuring the latent image, the size distribution can be corrected without actually forming a mask in the subsequent steps from development to etching.

Further, by measuring the latent image again after the second baking and confirming the in-plane uniformity, more precise management is possible. That is, when the in-plane uniformity cannot be obtained by the measurement of the latent image again, the partial second
It is possible to further improve the accuracy by repeatedly performing the baking and the measurement of the further latent image.

Although not particularly shown in the present embodiment, when a chemically amplified resist is used as the resist, a particularly great effect can be obtained. That is, in the chemically amplified resist, a dimensional change occurs depending on the elapsed time from the exposure time to the post-exposure baking. In particular, in the sequential exposure method using a charged particle beam, an exposure process in which the elapsed time in the substrate exceeds one hour is required. Further, when the exposure apparatus is in a vacuum atmosphere, a decrease in sensitivity, which is considered to be deactivation of a latent image in a vacuum, is recognized, and in-plane non-uniformity of dimensions occurs.

This dimensional variation shows different results for each substrate due to different patterns and different exposure times. When a chemically amplified resist is used, a conventional naphthoquinonediazide / novolak is used because the thermal reaction contributed by the acid catalyst generated by exposure occurs with diffusion and controls the dimensions after development. The dimensional change associated with the amount of baking treatment after exposure is greater than that of a system resist. Therefore, in-plane uniformity can be obtained by more accurate processing time or baking in a narrow temperature range.

The baking may be performed on a thick substrate such as a reticle blank as long as the temperature of only a resist film of about 1 μm can be controlled. By blowing the temperature-adjusted gas to the substrate, a temperature distribution that gradually attenuates from the center to the periphery of a specific region of the resist film, that is, a baking effect is obtained. In the present embodiment, a baking process is performed on a specific area in the substrate.
Non-contact heating means is desirable for the resist film.
Also, it is effective in dimensional control to provide a temperature distribution that gradually decreases from the center to the periphery. In other words, by performing partial baking with temperature-controlled airflow, it becomes possible to correct the dimensions of a predetermined portion in which the dimensions are continuously changed. Second Embodiment FIGS. 5 to 7 are views for explaining a pattern forming method according to a second embodiment of the present invention.
FIG. 6 is a flowchart until the correction data used in the pattern forming method according to the present embodiment is created, FIG. 6 is a flowchart showing a pattern forming process by the pattern forming method based on the created correction data, and FIG. 7 is used for the first baking process. 1 is a cross-sectional view of a baking device to be used.
The pattern forming method according to the present embodiment is performed in substantially the same steps as those in the first embodiment. However, without performing dimensional comparison after the first baking process, the first baking and the first baking are performed using correction data created in advance. 2 is greatly different in that the baking is continuously performed.

As shown in FIG. 5, the same test having pattern data of only contact holes is performed in substantially the same steps as in the first embodiment in order to generate correction data in order to obtain non-uniformity of the size distribution. Make three masks. Specifically, after resist application (1) and baking (pre-baking) (2) on the mask substrate, pattern exposure is performed by 10 μm.
Multiple writing is performed by exposing 2.5 μC / cm ² four times with an exposure amount of C / cm ² (3). The exposure time takes 28 minutes, and it takes 7 minutes to extract from vacuum to the atmosphere. Immediately after the mask subjected to the pattern exposure is taken out to the atmosphere, the mask is held on a hot plate held at 90 ° C. through a 0.2 mm spacer as shown in FIG. That is, bubbling is performed using a container containing ultrapure water to adjust the humidity. Next, air preheated to the same temperature as the hot plate is sent from the blower tube 71 toward the upper surface of the mask 13 to perform a first baking process (4).

After the first baking treatment for 15 minutes, the mask 13 is left on a plate kept at 23 ° C. After confirming that the mask 13 has returned to the room temperature of 23 ° C., a phenomenon process is performed (7). The development is performed by spraying a developing solution (manufactured by AD-10 Tama Chemical Co., Ltd.) at 23 ° C. from a full cone nozzle, rotating at 100 rpm for 90 seconds, and immediately rinsing with ultrapure water.

Next, baking (post baking) is performed at 100 ° C. for 20 minutes (8). Next, plasma descum processing using wet air is performed by a parallel plate type dry etching apparatus (9). Etching is 7
5 W for 5 minutes, so that the resist film thickness is about 0.05
μm.

Next, the chromium-based light-shielding film is etched for 20 minutes using a mixed gas of chlorine and oxygen (10).
In actual mask processing, the end point could not be detected because the area to be etched was as small as several percent in monitoring the intensity of the reflected RF wave.

After the etching is completed and the resist is removed, the dimension of a contact hole pattern having a design data of 1.0 μm square is measured with a confocal microscope (5). The dimension measurement measures the same point 16 times, so that the reliability of the measurement data can be confirmed. As a result of the dimension measurement of the mask obtained by the actual mask processing in the present embodiment, the three substrates show the same tendency, and the dimension gradually decreases by 15 nm from the exposure start point to the end position in the drawing order. Showed a tendency to go. The three substrates have in-plane dimensional variations of 35 nm and 41, respectively.
nm and 33 nm (3σ). If the dimensional correction is performed only on the three substrates in the y direction from the exposure start point toward the end direction, that is, in the direction perpendicular to the exposure stripe in the exposure apparatus, the in-plane dimensional variation becomes 29n.
It has been found that it can be reduced to m (3σ) or less. Through the steps described above, correction data for correcting dimensional non-uniformity can be created (51).

Next, a fourth substrate is prepared in order to confirm the accuracy of the correction data created in the above steps ((1) to (51)). Using this fourth substrate, the same resist coating (1) to pattern exposure (3) as performed on the first to third substrates by the baking apparatus shown in FIG. 7 according to the flowchart shown in FIG. And a first baking process (4) for 15 minutes. As shown in FIG. 4, the fourth substrate is immediately transferred to the cooling plate 15 after the first baking process, and the cooling air is applied to the cooling plate 15 from the exposure start point side of the substrate by the baking plate. The same blast is performed. In the present embodiment, unlike the first embodiment, the width is not a spot-shaped air flow, and the width is 1 mm up to 15 mm outside on one side compared to the width of the substrate.
Ventilation is performed only for a rectangular opening slit of 5 mm (6). Therefore, the stage is not moved in the x direction, and
The air is blown by continuously moving the stage only in the direction.

As shown in FIG. 4, a skirt-shaped plate having a width of 60 mm is provided on both sides of the slit in parallel with the substrate. The slit is separated from the substrate by 10 mm.
After blowing at 90 ° C. for 4 minutes and 30 seconds, the cooling plate 15 is moved downward by 20 cm, the mask 13 is separated from the blower pipe 17 and the blowing is stopped. After confirming that the substrate has returned to the room temperature of 23 ° C., the above-described development processing, descum and etching are performed ((7) to (10)). After the removal of the resist, the same latent image measurement as that of the three substrates is performed to obtain a size distribution. In actual mask processing, the average value of the dimensions is 0.98 μm, and the variation is 27 nm (3
σ). By the processing of the fourth substrate, the accuracy of the created correction data can be confirmed, and the stability of the mask forming process can be confirmed.

Next, in order to actually form a desired mask,
Prepare a fifth substrate. The fifth substrate is exposed using data which is a contact hole pattern but has about 1.8 times more patterns than the fourth substrate. The exposure time is about 50 minutes, which is about twice that of the fourth substrate. The air supply processing time on the cooling plate in the processing of the fourth substrate is changed to 10 minutes, and the other processes are applied to the fifth substrate by applying the same steps as in the case of the fourth substrate. In actual mask processing, the finished dimensions are
The average value was 1.02 μm, and the variation was 25 nm (3σ). Therefore, by changing the second baking processing time according to the fluctuation of the exposure time, the nonuniformity of the dimension of the resist film can be reduced as in the case of the fourth substrate.

As described above, even when the second baking is performed as in the first embodiment, the step of performing the dimension measurement can be omitted. That is, the size distribution after performing uniform baking on the resist film is measured in advance, and the first and second baking can be performed continuously when forming another resist film based on this size distribution. Therefore, it is possible to form a pattern with a small number of steps without performing a dimension measurement in the middle of a step of actually forming a mask. In addition, since the dimension measurement is performed on a test mask completed by actually performing the etching process, highly accurate measurement data can be obtained.

Although the gist of the present invention has been described using the first and second embodiments, the second baking used in the present invention is applied in addition to the first baking. Is also possible. For simultaneous execution, accurate prediction is required in advance, but sufficient effects can be expected with a simple method.

Further, in the first and second embodiments, the case where the blowing means is used as the baking device has been described. However, it is also possible to heat the surface of the substrate with a structure to which radiant heat can contribute. Heating by a light beam outside the photosensitive region of the resist does not depart from the gist of the present invention. It is obvious that the effect can be obtained by heating only the resist film. Further, in the first and second embodiments, the dimensions are changed by adding the second baking, but the dimensions can be controlled by partially cooling or stopping the baking. That is, irrespective of whether the temperature-controlled air is for heating or for cooling, uniformity of dimensions can be achieved by partially selecting a region to be dimensionally adjusted. Further, in the first and second embodiments, the second baking process is performed by different scanning methods.
Any scanning method can be selected according to the obtained measurement data.

In the second baking, the case where partial baking is performed by changing the scanning speed of the blower tube 17 has been described. However, the partial baking is performed by changing the temperature of air blown from the blower tube 17. Can also be performed.

In this embodiment, an example in which the present invention is applied for the purpose of achieving dimensional uniformity has been described. However, there is also a case where a dimensional distribution is generated depending on a process such as element manufacturing. For example, there is a case where the manufacturing process is non-uniform concentrically within the wafer, and it is expected that by distributing the resist pattern dimensions concentrically, the non-uniformity can be offset by a subsequent process. In this case, the in-plane uniformity is not achieved by the second baking process, but the process is performed so as to have a non-uniform predetermined size distribution.

Although the mask processing step has been described by way of example, any other than the mask may be used as long as it includes a step of forming a resist pattern and a subsequent baking process, such as a semiconductor substrate. In the first and second embodiments, different baking apparatuses are used as the first baking processing. However, any apparatus can be used selectively. Further, the present invention is not limited to the numerical values shown in the above embodiment, and can be implemented with various changes.

[0052]

As described above, according to the pattern forming method of the present invention, the post-exposure bake process is divided into two stages, a first and a second bake process. In the second baking process, the partial baking is performed so as to correct the non-uniformity of the dimensions obtained in the first baking process. As a result, a more accurate lithography process can be realized.

When a chemically amplified resist is used, the dimensional change accompanying the amount of baking after exposure is large, so that the in-plane non-uniformity due to dimensional fluctuation factors such as the elapsed time after pattern exposure is large. The second baking processing conditions according to
In-plane uniformity can be obtained in a shorter time than a normal resist, and a highly accurate lithography process can be realized.

[Brief description of the drawings]

FIG. 1 is a flowchart of a pattern forming method according to a first embodiment of the present invention.

FIG. 2 is a sectional view of an apparatus for performing a first baking process in the pattern forming method according to the first embodiment of the present invention.

FIG. 3 is a view showing a size distribution of a pattern formed by the pattern forming method according to the embodiment.

FIG. 4 is an exemplary sectional view of an apparatus for performing a second baking process in the pattern forming method according to the embodiment;

FIG. 5 is a flowchart until a correction data is created in a pattern forming method according to a second embodiment of the present invention.

FIG. 6 is a flowchart of a pattern forming method using correction data according to a second embodiment of the present invention.

FIG. 7 is a sectional view of an apparatus for performing a first baking process in a pattern forming method according to a second embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 11 spacer 12 hot plate 13 mask 14 x, y stage 15 cooling plate 16 auxiliary plate 17, 71 blower tube

Claims (5)

[Claims] In a pattern forming method of performing a pattern exposure on a resist film formed on a substrate to be processed, and performing a baking and a developing process after the pattern exposure, the post-exposure baking is performed in the first step. And the second step,
And the first step is performed uniformly on the entire resist film,
A pattern forming method, wherein the second step is partially performed so as to correct and uniform the in-plane non-uniformity of the dimensional distribution obtained in the first step. 2. A step of performing pattern exposure on a resist film formed on a substrate to be processed, a first baking step of uniformly baking the entire resist film after the pattern exposure, A step of measuring the size distribution of the resist film after baking, and a second baking step of partially baking so as to correct the in-plane non-uniformity based on the measured size distribution and make it uniform. Developing the resist film after the second baking. 3. A step of performing pattern exposure on a resist film formed on the substrate to be processed, a first baking step of uniformly baking the entire resist film after the pattern exposure, and A second baking step of partially baking so as to correct and uniform the in-plane non-uniformity based on the measurement result of the in-plane non-uniformity of the dimension distribution, and a resist film after the second baking And a step of developing the pattern. 4. The pattern forming method according to claim 1, wherein said resist is a chemically amplified resist. 5. The method according to claim 1, wherein the second baking is to blow the gas whose temperature is controlled so that the blown area achieves in-plane uniformity. The pattern forming method described in the above.