JP2013104934A - Exposure device and exposure method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adjust an exposure amount for each area set finely in a substrate surface, to improve uniformity of a resist residual film after development processing and to suppress variations in a line width and pitch of a wiring pattern.SOLUTION: An exposure device 1 exposes a pattern of an original plate M on an original plate stage 3 on a substrate G on a substrate stage 2 while performing a synchronous movement of the substrate G and the original plate M. The exposure device 1 includes a local exposure section 20 provided on an upper side of the substrate stage 2 to locally irradiate the substrate G with light, and a control section 40 for controlling a light emission drive of the local exposure section 20. The local exposure section 20 includes a plurality of light emitting elements L which are disposed in a line shape in a substrate width direction and are capable of irradiating the substrate G moved by the substrate stage 2 with light, and a light emission drive section 25 capable of selectively light-emission driving one or a plurality of light emitting elements L as a light emission control unit, among the plurality of light emitting elements L.

Description

  The present invention relates to an exposure apparatus and an exposure method for performing an exposure process on a substrate to be processed on which a photosensitive film is formed, and more particularly to an exposure apparatus and an exposure method capable of locally adjusting an exposure amount.

For example, in manufacturing an FPD (flat panel display), a circuit pattern is formed by a so-called photolithography process.
In this photolithography process, as described in Patent Document 1, after a predetermined film is formed on a target substrate such as a glass substrate, a photoresist (hereinafter referred to as a resist) is applied, A resist film (photosensitive film) is formed by a predrying process (vacuum drying and prebaking process) for evaporating the solvent. Then, the resist film is exposed corresponding to the circuit pattern, developed, and patterned.

  By the way, in such a photolithography process, as shown in FIG. 15A, the resist pattern R is provided with different film thicknesses (thick film portion R1 and thin film portion R2), and this is used for a plurality of times. By performing this etching process, the number of photomasks and the number of steps can be reduced. In addition, such a resist pattern R can be obtained by a half (halftone) exposure process using a halftone mask having a portion with different light transmittance.

A circuit pattern forming process using the resist pattern R to which the half exposure is applied will be specifically described with reference to FIGS.
For example, in FIG. 15A, on a glass substrate G, a Si composed of a gate electrode 200, an insulating layer 201, an a-Si layer (non-doped amorphous Si layer) 202a and an n + a-Si layer 202b (phosphorus-doped amorphous Si layer). A layer 202 and a metal layer 203 for forming an electrode are sequentially stacked.
Further, after a resist film is uniformly formed on the metal layer 203, the solvent in the resist is evaporated by drying under reduced pressure and pre-baking treatment, and then the resist pattern R is obtained by the half exposure processing and development processing. Is formed.

After the formation of this resist pattern R (thick film portion R1 and thin film portion R2), as shown in FIG. 15B, the metal layer 203 is etched (first etching) using this resist pattern R as a mask. .
Next, the entire resist pattern R is subjected to ashing (ashing) in plasma. As a result, as shown in FIG. 15C, a resist pattern R3 having a film thickness reduced to about half is obtained.
Then, as shown in FIG. 15D, etching (second etching) is performed on the exposed metal layer 203 and Si layer 202 using the resist pattern R3 as a mask, and finally, FIG. As shown in FIG. 4, a circuit pattern is obtained by removing the resist R3.

  However, in the half exposure process using the resist pattern R in which the thick film R1 and the thin film R2 are formed as described above, when the thickness of the resist pattern R is not uniform in the substrate plane, There is a problem that the line width of the pattern to be formed and the pitch between patterns vary.

16A to 16E, FIG. 16A shows the thickness t2 of the thin film portion R2 in the resist pattern R shown in FIG. The case where it formed thicker than thickness t1 is shown.
In this case, similarly to the process shown in FIG. 15, the etching of the metal film 203 (FIG. 16B) and the ashing process (FIG. 16C) for the entire resist pattern R are performed.

Here, as shown in FIG. 16C, a resist pattern R3 having a film thickness reduced to about half is obtained, but the thickness of the resist film to be removed is the same as in FIG. 15C. Therefore, the pitch p2 between the illustrated pair of resist patterns R3 is narrower than the pitch p1 shown in FIG.
Therefore, the circuit pattern obtained by etching the metal film 203 and the Si layer 202 (FIG. 16D) and removing the resist pattern R3 (FIG. 16E) from that state has a pitch p2 of FIG. It was narrower than the pitch p1 shown in (e) (the line width of the circuit pattern was wide).

Conventionally, for each of the above-described problems, for each mask pattern that transmits light during the exposure process, a predetermined part where the film thickness in the resist pattern R is formed to be thicker than a desired value is specified by film thickness measurement, and the exposure sensitivity of the part is determined. Measures are taken to increase
That is, in the pre-baking process in which the resist film is heated before the exposure process to evaporate the solvent, the amount of heating in the substrate surface is made different, and the exposure sensitivity at the predetermined portion is changed, so that the remaining film after the development process The thickness is adjusted (in-plane uniformity).
Specifically, the heater used for the pre-bake process is divided into a plurality of regions, and the temperature adjustment for each area is performed by independently driving and controlling the divided heaters.
Further, the heating temperature is adjusted by changing the height of the proximity pin that supports the substrate (changing the distance between the heater and the substrate).

JP 2007-158253 A

However, when adjusting the remaining film thickness by heat treatment by pre-baking as described above, the divided heater area needs to be secured to some extent due to hardware restrictions, so heating of a fine area There was a problem that adjustment was not possible.
Moreover, in the heating adjustment by the height of a proximity pin, since the work man-hour which changes a pin height is required, there existed a subject that production efficiency fell.

  The present invention has been made in view of the above-described problems of the prior art, and can easily adjust the exposure amount for each finely set area in the substrate surface, and the resist residual film after development processing There are provided an exposure apparatus and an exposure method capable of improving the uniformity of the wiring pattern and suppressing variations in the line width and pitch of the wiring pattern.

  In order to solve the above-described problems, an exposure apparatus according to the present invention holds a substrate to be processed on which a photosensitive film is formed, and a substrate stage that is movable in the scanning direction and an original plate on which a predetermined circuit pattern is formed. An original stage that is movable in synchronization with the substrate stage, an illumination optical system that irradiates the original with light, and a pattern of the original that is irradiated by the illumination optical system is projected onto the substrate. An exposure apparatus that exposes a pattern of the original on the substrate while moving the substrate on the substrate stage and the original on the original stage synchronously, and is provided above the substrate stage. And a local exposure unit for locally irradiating the substrate with light.

The local exposure unit is arranged in a line shape in the substrate width direction and is capable of irradiating light onto the substrate moved by the substrate stage, and one or more of the plurality of light emitting devices It is desirable to have a light emission drive unit capable of selectively driving light emission using a plurality of light emitting elements as light emission control units.
A controller that controls a light emission driving unit of the local exposure unit; the control unit controls the light emission driving unit, and one or a plurality of light emitting elements among the plurality of light emitting elements are controlled to emit light; It is desirable to emit light selectively.
The local exposure unit may be disposed above the substrate to be processed that is moved by the substrate stage, and may directly irradiate the photosensitive film formed on the substrate to be processed.
Alternatively, the local exposure unit is disposed above the original plate and irradiates the original plate, and diffracted light transmitted through the original plate passes through the projection optical system and is formed on the photosensitive film formed on the substrate to be processed. It is good also as a structure irradiated.

By configuring in this way, it is possible to easily perform local exposure processing on an arbitrary portion where it is desired to make the film thickness thinner (or thicker), and to obtain a desired film thickness with a preset exposure amount (illuminance). Can be reduced.
Therefore, for example, even when the resist film has different film thicknesses (thick film part and thin film part) in the half exposure process (that is, even if the film thickness is as thin as the thin film part), the resist after the development process The film thickness can be made uniform and variations in the line width and pitch of the wiring pattern can be suppressed.

In addition, the control unit stores a relationship between the illuminance irradiated on the substrate and the driving current value of the light emitting element as a correlation table, and the film thickness of a predetermined region of the photosensitive film formed on the substrate And determining a driving current value from the required illuminance based on the correlation table for the light emitting element that can irradiate the predetermined region, and the light emitting element based on the driving current value. It is desirable to control the light emission drive unit to emit light.
The illuminance detecting means is provided to detect the illuminance of the light irradiated by the local exposure unit, and is provided so as to be movable back and forth in the substrate width direction at the same height position as the substrate to be processed. It is desirable to hold the relationship between the illuminance detected by the detection means and the drive current value of the light emitting element driven to emit light as the correlation table.
Further, the control unit divides the plurality of light emitting elements into a plurality of light emission control groups along the substrate width direction, and a plurality of drive current values within a predetermined range and the drive current values for each of the light emission control groups. It is desirable to store the illuminance by the correlation table.
As described above, the illuminance of the light emitting element can be optimized by using the correlation table indicating the relationship between the drive current value of the light emitting element and the illuminance.
In addition, the value recorded in the correlation table is obtained by measuring the illuminance on all the light emitting elements as the light emission control unit in advance using the illuminance detecting means and recording the drive current value. The exposure amount can be adjusted with high accuracy.
Further, by dividing the plurality of light-emitting elements into a plurality of light-emission control groups, variation in light emission illuminance among the light-emitting elements can be suppressed.

Alternatively, the control unit may relate the variation value of the film thickness increased or decreased by irradiation and development processing to a predetermined area of the photosensitive film formed on the substrate to be processed and the drive current value of the light emitting element irradiated to the predetermined area. May be stored in a correlation table, a drive current value may be determined from the film thickness variation value based on the correlation table, and the light emission drive unit may be controlled to cause the light emitting element to emit light based on the drive current value.
When using correlation data between the film thickness variation value and the drive current value in this way, the illuminance can be omitted as a parameter (that is, it is not necessary to use the correlation data between the illuminance and the drive current value). Updating the correlation data between the illuminance and the drive current value can be omitted.

In addition, a light diffusion plate is provided below the plurality of light emitting elements included in the local exposure unit, and light emitted from the light emitting elements is emitted to the substrate to be processed through the light diffusion plate. Is desirable.
By providing a light diffusing plate in this way, light emitted from a plurality of light emitting elements is appropriately diffused by the light diffusing plate, so that light from adjacent light emitting elements is connected in a line and irradiated downward. Can do.

  In order to solve the above-described problem, an exposure method according to the present invention holds a substrate to be processed on which a photosensitive film is formed, and a substrate stage movable in a scanning direction and a predetermined circuit pattern are formed. An original stage that is movable in synchronization with the substrate stage, an illumination optical system that irradiates light to the original, and a pattern of the original that is irradiated by the illumination optical system on the substrate. An exposure apparatus comprising: a projection optical system for projecting: an exposure method for exposing the pattern of the original on the substrate, wherein the original on the substrate stage and the original on the original stage are moved synchronously The pattern is exposed on the substrate, and the substrate is irradiated with light locally by a local exposure unit provided above the substrate stage. To.

In the local exposure unit, one or a plurality of light emitting elements are selectively driven as light emission control units for a plurality of light emitting elements arranged in a line in the substrate width direction, and moved by the substrate stage. It is desirable to irradiate the substrate with light locally.
In addition, it is desirable that light is directly irradiated to the photosensitive film formed on the substrate to be processed by the local exposure unit.
Alternatively, the local exposure unit irradiates the original from above the original, and diffracted light transmitted through the original passes through the projection optical system and is applied to the photosensitive film formed on the substrate to be processed. May be.

According to such a method, it is possible to easily perform a local exposure process on an arbitrary part where it is desired to make the film thickness thinner (or thicker), and to obtain a desired film thickness by a preset exposure amount (illuminance). Can be reduced.
Therefore, for example, even when the resist film has different film thicknesses (thick film part and thin film part) in the half exposure process (that is, even if the film thickness is as thin as the thin film part), the resist after the development process The film thickness can be made uniform and variations in the line width and pitch of the wiring pattern can be suppressed.

Further, the relationship between the illuminance irradiated on the substrate and the drive current value of the light emitting element is stored as a correlation table, and a predetermined region of the photosensitive film formed on the substrate is irradiated based on the film thickness. Determining a necessary illuminance, determining a driving current value from the necessary illuminance based on the correlation table for the light emitting element capable of irradiating the predetermined region, and causing the light emitting element to emit light based on the driving current value. desirable.
In addition, the illuminance detection means provided so as to be capable of moving back and forth in the substrate width direction at the same height position as the substrate to be processed measures illuminance on all the light emitting elements that are light emission control units in the local exposure unit. It is desirable to hold the relationship between the drive current value and illuminance as the correlation table.
Further, the plurality of light emitting elements are divided into a plurality of light emission control groups along the substrate width direction, and for each light emission control group, a plurality of drive current values within a predetermined range and illuminance by the drive current values are It is desirable to store in the correlation table.
As described above, the illuminance of the light emitting element can be optimized by using the correlation table indicating the relationship between the drive current value of the light emitting element and the illuminance.
In addition, the value recorded in the correlation table is obtained by measuring the illuminance on all the light emitting elements as the light emission control unit in advance using the illuminance detecting means and recording the drive current value. The exposure amount can be adjusted with high accuracy.
Further, by dividing the plurality of light-emitting elements into a plurality of light-emission control groups, variation in light emission illuminance among the light-emitting elements can be suppressed.

Alternatively, the relationship between the fluctuation value of the film thickness increased / decreased by irradiation and development processing on a predetermined area of the photosensitive film formed on the substrate to be processed and the drive current value of the light emitting element irradiated to the predetermined area is stored in the correlation table. Then, a driving current value may be determined from the film thickness variation value based on the correlation table, and the light emitting element may be caused to emit light based on the driving current value.
When using correlation data between the film thickness variation value and the drive current value in this way, the illuminance can be omitted as a parameter (that is, it is not necessary to use the correlation data between the illuminance and the drive current value). Updating the correlation data between the illuminance and the drive current value can be omitted.

In the local exposure unit, it is preferable that light emitted from the light emitting element is emitted to the substrate to be processed through a light diffusion plate provided below the plurality of light emitting elements.
Thus, by diffusing the light radiated from the plurality of light emitting elements with the light diffusion plate, the light of the adjacent light emitting elements can be connected in a line and irradiated downward.

  According to the present invention, it is possible to easily adjust the exposure amount for each finely set area in the substrate surface, improve the uniformity of the resist residual film after development processing, and vary the line width and pitch of the wiring pattern. It is possible to obtain an exposure apparatus and an exposure method that can suppress the above.

FIG. 1 is a sectional view showing an overall schematic configuration of an embodiment of an exposure apparatus according to the present invention. FIG. 2 is a plan view of a substrate stage provided in the exposure apparatus of FIG. FIG. 3 is a cross-sectional view of a local exposure unit provided in the exposure apparatus of FIG. FIG. 4 is a front view of the main part of the local exposure unit in FIG. 3 as viewed from the substrate width direction. FIG. 5 is a plan view showing the arrangement of the light emitting elements constituting the light source. FIG. 6 is a flowchart showing a process for obtaining setting parameters of the light emission control program included in the exposure apparatus according to the present invention. FIG. 7 is a diagram for explaining the light emission control of the light emitting element in the exposure apparatus according to the present invention, and is a plan view of the substrate to be processed showing the local exposure position on the substrate to be processed by coordinates. FIG. 8 is a table showing an example of setting parameters of the light emission control program included in the exposure apparatus according to the present invention. FIG. 9 is a table showing an example of a correlation table between the drive current value of the light emitting element and the illuminance used in the light emission control program included in the exposure apparatus according to the present invention. FIG. 10 is a flow showing a series of operations according to the exposure position according to the present invention. FIG. 11 is a plan view for explaining the operation of local exposure in the exposure apparatus according to the present invention. FIG. 12 is a graph for explaining the operation of local exposure in the exposure apparatus according to the present invention. FIG. 13 is a sectional view showing another embodiment of the exposure apparatus according to the present invention. FIG. 14 is a table showing an application example of the correlation table between the drive current value of the light emitting element and the film thickness that can be used in the light emission control program of the exposure apparatus according to the present invention. FIG. 15A to FIG. 15E are cross-sectional views for explaining a wiring pattern forming process using a half exposure process. 16A to 16E are views showing a wiring pattern forming process using a half exposure process, and are cross-sectional views showing a case where the resist film thickness is thicker than that in FIG.

Hereinafter, an embodiment of an exposure apparatus and an exposure method of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a schematic configuration inside an exposure apparatus 1 according to the present invention.
The exposure apparatus 1 is, for example, a step-and-scan type projection exposure apparatus, which scans a rectangular mask M (original) and a glass substrate G (substrate to be processed) in synchronization with each other, and has a circuit pattern that the mask M has. Is projected onto a resist film (photosensitive film) on the glass substrate G and exposed.

As shown in the figure, the exposure apparatus 1 includes a substrate stage 2 on which a glass substrate G coated with a resist solution is placed, and a projection optical system 10 disposed above the substrate stage 2. Further, a mask stage 3 that holds a mask M is provided above the projection optical system 10.
Furthermore, the exposure apparatus 1 includes an illumination unit 5 (illumination optical system) disposed above the mask M and a local exposure unit that is formed long in the substrate width direction and locally irradiates light toward the substrate G. 20.

The substrate stage 2 supports the substrate G and moves it in the XYZ axial directions. The substrate stage 2 has a drive mechanism (not shown) that moves the stage in each direction.
On the other hand, the mask stage 3 is a frame that supports the mask M and has an opening (not shown) so that the mask M faces the projection optical system 10 below. The mask stage 3 has a drive mechanism (not shown) that moves the mask M in the Y direction that is the scanning direction.

The substrate stage 2 and the mask stage 3 are scanned synchronously with each other in the Y direction at a speed ratio corresponding to the imaging magnification of the projection optical system 10, thereby enabling exposure over a wide area.
Further, after the scanning exposure is completed, the glass substrate G can be exposed to a plurality of shots (exposure areas) by stepping the substrate stage 2 by a predetermined amount in the X direction and repeating the scanning exposure in the Y direction. ing. In the present embodiment, as shown in FIG. 2 (plan view of the substrate stage 2), four shot regions SA1 to SA4 are provided on the glass substrate G as an example.

  The projection optical system 10 maintains the mask M and the glass substrate G in an optically conjugate relationship, and projects an image of the pattern of the mask M onto the glass substrate G. In the present embodiment, the projection optical system 10 is configured as a catadioptric optical system that uses an off-axis good image area, and includes a trapezoidal mirror 11, a concave mirror 12, and a convex mirror 13. Yes. In the exposure apparatus according to the present invention, the configuration of the projection optical system 10 is not limited to the above configuration, and a refractive system or a reflection system may be used instead as the projection optical system 10.

The illuminating unit 5 converts a light beam as exposure light emitted from a light source (not shown) composed of a high-pressure mercury lamp or an excimer laser into an arc-shaped light beam by an illumination optical system (not shown), and Uniform illumination.
As shown in FIG. 2, the arc-shaped diffracted light LT1 transmitted through the mask M sequentially passes through the trapezoidal mirror 11, the concave mirror 12, the convex mirror 13, the concave mirror 12, and the trapezoidal mirror 11, and the substrate stage 2 (glass It reaches the substrate G).

The local exposure unit 20 directly irradiates a predetermined region of the resist film applied and formed on the glass substrate G with the light LT2 to perform local exposure. As the resist, for example, a positive resist is used. If used, it is driven as follows. That is, when continuously processing a plurality of substrates G, when the wiring pattern width is wider and the inter-pattern pitch is narrower than the other regions in the predetermined regions of all the substrates G, Local exposure) is applied.
In the following embodiment, the case of a positive resist will be described as an example. However, the exposure apparatus according to the present invention can be applied to a case of a negative resist, in which case In this case, local exposure is applied to a predetermined region where the resist residual film is desired to be left thicker.

Next, the configuration of the local exposure unit 20 will be described in more detail. FIG. 3 is a cross-sectional view of the local exposure unit 20. FIG. 4 is a front view of the main part of the local exposure unit 20 as viewed from the substrate width direction.
The local exposure unit 20 is provided to perform local exposure (UV light emission) on the substrate G, and is located above the substrate stage 2 and at a place that does not affect the projection optical system 10 as shown in FIG. Be placed.
3 and 4, the local exposure unit 20 includes a linear light source 21 extending in the substrate width direction (Y direction), and the substrate G on the substrate stage 2 is in the scanning direction below the light source 21. (X direction) will be moved.

The linear light source 21 emits a plurality of UV-LED elements L that emit UV light of a predetermined wavelength (for example, a wavelength close to any of g-line (436 nm), h-line (405 nm), and i-line (364 nm)). Are arranged on the circuit board 22.
For example, FIG. 5A is a plan view of the circuit board 22 of the light source 21 as viewed from below. As shown in FIG. 5A, on the circuit board 22, a plurality of UV-LED elements L are arranged in three rows.

Here, as shown in FIG. 5A, a plurality of (9 in the figure) UV-LED elements L form one light emission control unit (light emission control groups GR1 to GRn). Thus, by using a plurality of LED elements L as a light emission control unit, it is possible to suppress variations in light emission illuminance between the light emitting elements.
Further, the irradiation range on the substrate G by one light emission control group GR is significantly smaller than the irradiation range of the arc-shaped diffracted light LT1 irradiated on the substrate G from the projection optical system 10. For this reason, it is possible to locally adjust the exposure amount by the light emission control of the plurality of light emission control groups GR within the irradiation range of the arc-shaped diffracted light LT1.
When the light source 21 is configured with fewer UV-LED elements L, the staggered pattern is formed so that the elements L overlap in the scanning direction (X direction) and the substrate width direction (Y direction) as shown in FIG. It is desirable to arrange.

As shown in FIGS. 3 and 4, a light emission window 23 made of a light diffusing plate is provided below the light source 21. In other words, the light emission window 23 is disposed between the light source 21 and the substrate G that is an object to be irradiated.
Since the light radiating window 23 formed of the light diffusing plate is provided as described above, the light emitted from the light source 21 is appropriately diffused by the light radiating window 23. Therefore, the light of the adjacent UV-LED element L is a line. It is connected to the shape and irradiated downward.
Further, as shown in FIG. 3, a light reflecting wall 24 extending in the substrate width direction (Y direction) is provided in front of and behind the UV-LED element L, so that light emitted from the UV-LED element L is efficiently emitted from the light emission window 23. It is configured to radiate downward.

In addition, each light emission control group GR constituting the light source 21 is independently controlled by the light emission drive unit 25 (see FIG. 3). Furthermore, the forward current value supplied to each light emission control group GR (the UV-LED element L) can be controlled. That is, in the UV-LED elements L of each light emission control group GR, the light emission irradiance corresponding to the supplied current is made variable by the light emission drive unit 25.
The light emission drive unit 25 is controlled by a control unit 40 including a computer.

As shown in FIG. 1, an illuminance sensor 30 for detecting the illuminance (radiant flux) of the light emitted from the light source 21 and passed through the light radiation window 23 is provided at the edge on the substrate stage 2. Yes.
The illuminance sensor 30 is arranged with the signal detection unit facing upward, and the height position of the detection unit is adjusted to coincide with the height of the upper surface of the substrate G (resist film).
Here, since the substrate stage 2 is provided so as to be movable in the XY axial directions, the illuminance sensor 30 is moved directly below the UV-LED elements L of each light emission control group GR by the movement of the substrate stage 2. be able to. Therefore, the illuminance sensor 30 can receive the light LT2 emitted from the UV-LED elements L of each light emission control group GR. In the illuminance sensor 30 configured in this way, the illuminance of each light emission control group GR is measured, and the relationship between the current value supplied to the light emission control group GR (the LED element L) and the light emission illuminance is measured. Used to get.

Further, the control unit 40 controls the luminance of each light emission control group GR constituting the light source 21, that is, the current value supplied to each light emission control group GR (the UV-LED element L constituting the light emission control group GR) at a predetermined timing. The light emission control program P is stored in a predetermined recording area.
The light emission control program P is a recipe parameter used when executing the light emission control program P. Necessary illuminance (current value supplied to the light emission control group GR) to be radiated to a predetermined position of the substrate G and light emission to the predetermined position of the substrate G. Information for specifying the light emission control group GR to be controlled is set in advance.

Here, the preparatory process using the local exposure part 20 is demonstrated using FIG. 6 thru | or FIG. This preparation process is performed to determine a parameter (referred to as a recipe) for the exposure process for each mask pattern that transmits light during the exposure process. Specifically, it is carried out to fill each parameter in the recipe table T1 as shown in FIG. The recipe table T1 is stored and held in the control unit 40.
In addition, one of two types of sampling substrates (referred to as sampling targets 1 and 2) is used for this preparation step. First, the sampling target 1 is a substrate to be processed that has been subjected to half exposure and development processing after resist coating. On the other hand, the sampling target 2 is a substrate to be processed on which a wiring pattern is formed by a normal photolithography process.

As shown in FIG. 6, in the case of sampling target 1, a plurality of substrates to be processed that have been subjected to half exposure and development processing after resist coating are sampled (step St1 in FIG. 6).
Next, the resist residual film thickness in the surface of the sampled substrate G is measured (step St2 in FIG. 6), and a predetermined area AR to be thinned is schematically shown in FIG. , Y) (step St5 in FIG. 6).

On the other hand, as shown in FIG. 6, in the case of the sampling target 2, a plurality of substrates to be processed having wiring patterns formed by a normal photolithography process are sampled (step St3 in FIG. 6).
Next, the line width of the wiring pattern and the pitch between patterns in the surface of the sampled substrate G are measured (step St4 in FIG. 6), and a predetermined area AR to be thinned as shown in FIG. It is specified by the dimension coordinate value (x, y) (step St5 in FIG. 6).

When the predetermined area AR is specified, as shown in the recipe table T1 in FIG. 8, the control unit 40 has a film thickness reduction (for example, coordinates (x1, y1) required for each coordinate value in the predetermined area AR. In this case, 1000 cm) is calculated (step St6 in FIG. 6). Furthermore, the illuminance to be irradiated for film reduction (0.2 mJ / cm ^{2 in} the case of coordinates (x1, y1)) is calculated based on the value of the thickness reduction and various conditions such as the resist type (see FIG. 6 step St7).

Further, as shown in the recipe table T1 of FIG. 8, the control unit 40 identifies each light emission control group GR that can be irradiated with respect to each coordinate value of the predetermined area AR (step St8 in FIG. 6), and the light emission control. A forward current value necessary for causing the group GR to emit light with a desired illuminance is obtained from the correlation table T2 shown in FIG. 9 (step St9 in FIG. 6).
The correlation table T2 indicates the correlation between the illuminance value measured for each light emission control group GR and the current value, and is stored in the recording area of the control unit 40.

The correlation table T2 is regularly updated as follows, for example.
First, in a state where the light source 21 (light emission window 23) is set to a predetermined height, the substrate stage 2 is driven by a control signal from the control unit 40, and the illuminance sensor 30 is moved below the light emission window 23. Here, since the distance between the light emission window 23 and the illuminance sensor 30 is equal to the distance between the light emission window 23 and the upper surface of the substrate G, the illuminance detected by the illuminance sensor 30 is the illuminance irradiated on the substrate G. .

For each light emission control group GR, the forward current value supplied to the light emission control group GR of the light source 21 is increased or decreased within the rated current range, the light emission illuminance is detected by the illuminance sensor 30, and the relationship between the illuminance and the current value. Is stored in the correlation table T2 of FIG.
In this way, all parameters are obtained along the flow of FIG. 6 and set in the recipe table T1 of FIG. 8, and the preparation process is completed (step St10 of FIG. 6).

  Subsequently, a series of operations of the exposure processing by the exposure apparatus 1 will be described with reference to FIG. 10 (flow). In the present embodiment, exposure processing of the shot areas SA1 and SA2 shown in FIG. 2 is performed in scanning in the X direction (referred to as forward scanning), and then the substrate stage 2 is moved one step in the Y direction. It is assumed that exposure processing of the shot areas SA3 and SA4 is performed in the return scanning in the X direction (referred to as backward scanning).

  First, when a substrate G on which a resist film is formed is placed on the substrate stage 2 of the exposure apparatus 1 (step S1 in FIG. 10), the illumination unit 5 applies an arc-shaped light beam as exposure light to the mask M. Start lighting uniformly. The arc-shaped diffracted light LT1 transmitted through the mask M sequentially passes through the trapezoidal mirror 11, the concave mirror 12, the convex mirror 13, the concave mirror 12, and the trapezoidal mirror 11, and on the substrate stage 2 as shown in FIG. G side) (step S2 in FIG. 10).

Further, the substrate stage 2 starts to move in the X direction (leftward direction in FIG. 2) in synchronism with the mask stage 3 (that is, the forward scanning starts), so that the shape of the circuit pattern formed on the mask M is obtained. Exposure of the resist film (shot areas SA1, SA2) on the substrate G is started (step S3 in FIG. 10).
Further, in this forward scanning, the control unit 40 is schematically shown in FIG. 11 at a timing when a predetermined area on the substrate G to be locally exposed passes below the local exposure unit 20 (step S4 in FIG. 10). As shown in FIG. 10, the light emission control of the light emission control groups GR1 to GRn constituting the light source 21 is performed (step S5 in FIG. 10).

Here, for example, in the case of emitting light to the predetermined area AR of the substrate G, the light emission control groups GRn-1 and GRn-2 arranged above the light emission control group are performed, and the predetermined area AR is directly controlled. Light LT2 is irradiated. More specifically, as shown in the graph of FIG. 12 (the size of the radiant flux (watt) with respect to time for each light emission control group GRn-1 and GRn-2), the predetermined area AR of the substrate G is below the light source. During the passage, the forward current supplied is controlled so that the magnitude of the radiant flux W changes.
In this manner, not only the predetermined area AR of the substrate G is irradiated but also irradiation with an arbitrary illuminance is performed locally in the area AR.

If there is another area to be locally exposed on the substrate G (step S6 in FIG. 10), the light emission control of the light emission control group GR is performed in that area, and if there is no other area (step S6 in FIG. 10). ), The local exposure process for the substrate G is completed.
When the forward scanning with the arc-shaped diffracted light LT1 that has passed through the mask M and the projection optical system 10 is completed (step S7 in FIG. 10), the control unit 40 moves the substrate stage 2 stepwise in the Y direction, and the mask stage 3 And the substrate stage 2 are started to move in the X direction (right direction in FIG. 2) while synchronizing with the X direction. Thereby, the backward scanning is started, and the exposure of the remaining shot areas SA3 and SA4 is started in order (step S8 in FIG. 10).
When the backward scanning is completed, the control unit 40 stops the projection of the light beam from the illumination unit 5, and the exposure process including the local exposure in the exposure apparatus 1 is completed (step S9 in FIG. 10).

As described above, according to the embodiment of the present invention, when the exposure apparatus 1 performs the exposure process on the resist film formed on the substrate G, each shot area SA1 by the diffracted light LT1 through the mask M is used. In addition to the exposure process to -SA4, the local exposure unit 20 performs a local exposure process on an arbitrary part.
That is, in the local exposure unit 20 arranged above the substrate, a plurality of light emission control groups GR are formed by the plurality of UV-LED elements L arranged in a line shape in the substrate width direction (X direction) and moved below the plurality of light emission control groups GR. The selected emission control group GR is controlled to emit light to the substrate G to be processed.
Thereby, the local exposure process with respect to the arbitrary site | parts which want to make a film thickness thinner can be performed easily, and it can reduce to a desired film thickness with the preset exposure amount (illuminance).
Therefore, for example, even when the resist film has different film thicknesses (thick film part and thin film part) in the half exposure process (that is, even if the film thickness is as thin as the thin film part), the resist after the development process The film thickness can be made uniform and variations in the line width and pitch of the wiring pattern can be suppressed.
In setting the exposure amount (illuminance), the illuminance sensor 30 is used to measure all the light emission control groups GR in advance, and the relationship between the drive current value and the illuminance is held as a correlation table. Thus, the exposure amount can be adjusted with high accuracy.

In the embodiment, as shown in FIG. 1, the local exposure unit 20 is arranged behind the projection optical system 10 (left side in FIG. 1) along the scanning direction (X-axis direction). Although an example is shown, it is not limited to this, and any position that does not affect the passage of diffracted light in the projection optical system 10 may be used. For example, a configuration in which the projection optical system 10 is disposed in front of the projection optical system 10 (in the vicinity of directly below the convex mirror 13) is also possible.
Alternatively, local exposure units 20 may be arranged before and after the projection optical system 10 so that the local exposure unit 20 to be driven is switched between the forward scanning and the backward scanning.

Alternatively, as described above, the local exposure unit 20 is not arranged so as not to affect the projection optical system 10, but the mask M is irradiated with light emitted from the local exposure unit 20, and the projection optical system 10 is The exposure may be performed after being superimposed on the diffracted light LT1 passing therethrough.
In that case, for example, as shown in FIG. 13, a configuration in which the local exposure unit 20 is arranged behind the illumination unit 5 (on the left side in FIG. 1) can be considered.
According to the configuration shown in FIG. 13, the light emitted from the local exposure unit 20 passes through the mask M and exposes the substrate G via the projection optical system 10. For this reason, local exposure can be performed within the pattern region of the mask M, the chemical reaction in a region that does not require exposure can be suppressed, and the accuracy of local exposure can be further improved.

In the exposure apparatus 1, the local exposure unit 20 directly irradiates the substrate G with light as shown in FIG. 1, and the mask G is irradiated with light as shown in FIG. 13 via the projection optical system 10. In any case of the configuration for irradiating the light, the number of local exposure units 20 is not limited to one, and a plurality of local exposure units 20 may be arranged. For example, when the local exposure unit 20 directly irradiates the substrate G with light as shown in FIG. 1, the local exposure unit 20 may be disposed before and after the projection optical system 10 as described above. In the case of the configuration in which the mask M is irradiated with light and the substrate G is irradiated through the projection optical system 10 as shown in FIG. 13, the local exposure units 20 may be arranged before and after the illumination unit 5, respectively.
Moreover, the position where the local exposure units 20 are arranged in the exposure apparatus 1 and the number thereof are not limited, and one or a plurality of local exposure units 20 may be arranged at each position (for example, at each position). A plurality of local exposure sections 20 are arranged so as to be connected in parallel along the scanning direction).

Moreover, in the said embodiment, although the example which made the light emission control group which consists of several UV-LED element L the light emission control unit was shown, not only it but each UV-LED element L as a light emission control unit, Finer local exposure may be performed.
Moreover, in the said embodiment, although the case where the resist residual film thickness after a half exposure process was made uniform was demonstrated to the example, in the local exposure method which concerns on this invention, it applies not only to a half exposure process. Can do. For example, even when a normal exposure process is performed instead of a half exposure process, the resist residual film thickness can be made uniform in the plane by applying the local exposure method according to the invention.
Further, as in steps St6 and St7 of FIG. 6, not only the required illuminance is obtained based on the required remaining film thickness, but the pattern line width after the development processing is measured and the correlation data between the pattern line width and the illuminance. And a recipe table may be created based on the correlation data.

  In the embodiment, the illuminance to be irradiated is determined from the thickness of a predetermined region of the resist film formed on the substrate G, and the drive current value is obtained from the illuminance based on the correlation table. However, the present invention is not limited to such a form, and the relationship between the film thickness fluctuation value (thickness reduction value) in the predetermined area and the drive current value of the light emission control group GR irradiated to the predetermined area is shown in FIG. It is possible to store the data as a database in the correlation table T3 as shown in FIG. That is, the drive current value may be determined directly from the film thickness variation value of the predetermined region based on the correlation table T3, and the light emission control group GR may be caused to emit light based on the drive current value. When the correlation table T3 is used in this way, the illuminance can be omitted as a parameter (that is, the correlation table T2 between the illuminance and the drive current value does not need to be used), so the illuminance measurement using the illuminance sensor 31 is performed. The periodic update of the correlation table T2 can be omitted.

  In the above-described embodiment, the mask M is used as the original. However, the present invention is not limited to this, and a reticle or the like can be used as the original.

DESCRIPTION OF SYMBOLS 1 Exposure apparatus 2 Substrate stage 3 Mask stage (original stage)
5 Illumination unit (illumination optical system)
DESCRIPTION OF SYMBOLS 10 Projection optical system 11 Trapezoid mirror 12 Concave mirror 13 Convex mirror 20 Local exposure part 30 Illuminance sensor (illuminance detection means)
40 Control unit G Glass substrate (substrate to be processed)
L UV-LED element (light emitting element)
LT1 Diffracted light LT2 Light M Mask (original)
GR light emission control group T1 Recipe table T2 Correlation table T3 Correlation table

Claims (19)

A substrate stage that holds a substrate to be processed on which a photosensitive film is formed and that can move in the scanning direction, and an original plate stage that holds an original on which a predetermined circuit pattern is formed and can move in synchronization with the substrate stage. And an illumination optical system for irradiating light to the original plate, and a projection optical system for projecting the pattern of the original plate irradiated by the illumination optical system onto the substrate, the substrate on the substrate stage and the original stage An exposure apparatus that exposes a pattern of the original on the substrate while moving the upper original synchronously,
An exposure apparatus comprising: a local exposure unit that is provided above the substrate stage and irradiates light locally to the substrate. The local exposure part is
A plurality of light emitting elements arranged in a line in the substrate width direction and capable of irradiating light to the substrate moved by the substrate stage;
The exposure apparatus according to claim 1, further comprising: a light emission driving unit capable of selectively driving light emission using one or a plurality of light emitting elements as a light emission control unit among the plurality of light emitting elements. A control unit for controlling the light emission drive unit of the local exposure unit;
The control unit according to claim 2, wherein the control unit controls the light emission driving unit to selectively emit one or more light emitting elements among the plurality of light emitting elements as a light emission control unit. Exposure device. The controller is
The relationship between the illuminance irradiated on the substrate and the drive current value of the light emitting element is stored as a correlation table, and a predetermined region of the photosensitive film formed on the substrate should be irradiated based on the film thickness The light emission driving for determining the illuminance, determining a drive current value from the required illuminance based on the correlation table for the light emitting element capable of irradiating the predetermined area, and causing the light emitting element to emit light based on the drive current value 4. The exposure apparatus according to claim 3, wherein the exposure unit controls the exposure unit. Illuminance detecting means provided to be capable of moving back and forth in the substrate width direction at the same height position as the substrate to be processed, and comprising illuminance detection means for detecting the illuminance of light irradiated by the local exposure unit,
5. The exposure according to claim 4, wherein the control unit holds, as the correlation table, a relationship between the illuminance detected by the illuminance detection unit and the drive current value of the light emitting element driven to emit light. apparatus. The controller is
The plurality of light-emitting elements are divided into a plurality of light-emission control groups along the substrate width direction, and a plurality of drive current values within a predetermined range and illuminance based on the drive current values for each light-emission control group 6. The exposure apparatus according to claim 4 or 5, wherein the exposure apparatus stores the information in the exposure apparatus.   The control unit correlates a relationship between a fluctuation value of the film thickness increased or decreased by irradiation and development processing on a predetermined area of the photosensitive film formed on the substrate to be processed and a driving current value of the light emitting element irradiated to the predetermined area. 4. The light emission driving unit is controlled so as to accumulate in a table, determine a drive current value from the film thickness variation value based on the correlation table, and cause the light emitting element to emit light based on the drive current value. The exposure apparatus described in 1.   The local exposure unit is disposed above the substrate to be processed that is moved by the substrate stage, and directly irradiates light to a photosensitive film formed on the substrate to be processed. The exposure apparatus according to claim 7.   The local exposure unit is disposed above the original and irradiates the original, and diffracted light transmitted through the original passes through the projection optical system and is applied to a photosensitive film formed on the substrate to be processed. The exposure apparatus according to claim 1, wherein the exposure apparatus is an exposure apparatus. A light diffusion plate is provided below the plurality of light emitting elements of the local exposure unit,
10. The exposure apparatus according to claim 2, wherein light emitted from the light emitting element is emitted to the substrate to be processed through the light diffusion plate. A substrate stage that holds a substrate to be processed on which a photosensitive film is formed and that can move in the scanning direction, and an original plate stage that holds an original on which a predetermined circuit pattern is formed and can move in synchronization with the substrate stage. And an exposure optical system that irradiates the original with light and a projection optical system that projects the original pattern irradiated by the illumination optical system onto the substrate. An exposure method that exposes the top,
While exposing the substrate pattern on the substrate while synchronously moving the substrate on the substrate stage and the original plate on the original stage,
An exposure method comprising irradiating light locally to the substrate by a local exposure unit provided above the substrate stage. In the local exposure unit, with respect to the plurality of light emitting elements arranged in a line in the substrate width direction, one or a plurality of light emitting elements are selectively driven to emit light as a light emission control unit,
12. The exposure method according to claim 11, wherein the substrate is moved by the substrate stage and is irradiated with light locally.   The relationship between the illuminance irradiated on the substrate and the drive current value of the light emitting element is stored as a correlation table, and a predetermined region of the photosensitive film formed on the substrate should be irradiated based on the film thickness A driving current value is determined from the necessary illuminance based on the correlation table for the light emitting element that can irradiate the predetermined region, and the light emitting element is caused to emit light based on the driving current value. The exposure method according to claim 12.   The illuminance detection means provided so as to be able to move back and forth in the substrate width direction at the same height position as the substrate to be processed, measures the illuminance for all the light emitting elements that become the light emission control unit in the local exposure unit, The exposure method according to claim 13, wherein a relationship between a drive current value and illuminance is held as the correlation table.   The plurality of light-emitting elements are divided into a plurality of light-emission control groups along the substrate width direction, and a plurality of drive current values within a predetermined range and illuminance based on the drive current values for each of the light-emission control groups are stored in the correlation table. 15. The exposure method according to claim 13 or 14, wherein the exposure method is stored.   The relationship between the fluctuation value of the film thickness increased / decreased by irradiation and development processing on a predetermined area of the photosensitive film formed on the substrate to be processed and the drive current value of the light emitting element irradiated to the predetermined area is accumulated in a correlation table, 13. The exposure method according to claim 12, wherein a driving current value is determined from the film thickness variation value based on the correlation table, and the light emitting element is caused to emit light based on the driving current value.   The exposure method according to claim 11, wherein light is directly irradiated to the photosensitive film formed on the substrate to be processed by the local exposure unit. Irradiating the original from above the original by the local exposure unit,
17. The exposure according to claim 11, wherein the diffracted light that has passed through the original passes through the projection optical system and is applied to a photosensitive film formed on the substrate to be processed. Method.   13. The local exposure unit radiates light emitted from the light emitting element to the substrate to be processed through a light diffusing plate provided below the plurality of light emitting elements. The exposure method according to claim 18.

Images