JP2013186191A - Auxiliary exposing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To significantly improve accuracy of the film thickness or line width, or in-plane uniformity of a resist pattern after development processing in lithography.SOLUTION: An auxiliary exposing device (AE)10 of the present invention comprises: a flat-flowing conveyance section 30 for conveying a substrate G at a certain posture in one horizontal direction; a UV irradiation unit 32 for irradiating a resist on the substrate G with an ultraviolet (UV) of a predetermined wavelength; a light-emitting driving section 34 for supplying driving current for light emission to a light-emitting element in the UV irradiation unit 32; a cooling mechanism 36 for cooling the light-emitting element in the UV irradiation unit 32 to a preset temperature; an illuminance measurement section 38 for measuring the illuminance of ultraviolet irradiation by the UV irradiation unit 32; a control section 40 for controlling the sections in the device; and a memory 42.

Description

  The present invention relates to photolithography, and more particularly to an auxiliary exposure apparatus that irradiates ultraviolet rays separately from a normal exposure process for transferring a mask pattern to a resist film coated on a substrate to be processed.

  In optical lithography technology, a resist (photosensitive resin) is applied onto a thin film (processed film) deposited on the surface of a substrate to be processed, and a photomask pattern (circuit pattern) is transferred to the resist on the substrate. This is a technique for developing a resist pattern by developing. The photolithography technology is a key technology that affects the miniaturization and high density of integrated circuits in semiconductor devices and FPDs (flat panel displays).

  Until now, miniaturization of circuit patterns by photolithography has progressed in various ways. In recent years, the trend of miniaturization has been maintained by shortening the wavelength of ultraviolet rays used for exposure, adopting phase shift masks and chemically amplified resists, and the like. Specifically, the exposure wavelength of ultraviolet rays has shifted from 248 nm (Krf) to 193 nm (Arf). In addition, for example, the halftone phase shift mask method transmits a small amount of light even in a light shielding portion of a photomask, and interference occurs between the amplitude of light passing through the mask opening and the amplitude of transmitted light around the mask opening. The resolution performance is improved. The chemically amplified resist can obtain high sensitivity by an amplification reaction using an acid catalyst, and can achieve high development contrast and high resolution.

JP 2002-341525 A

  However, as circuit pattern miniaturization by photolithography advances as described above, the in-plane uniformity of the film thickness and line width of the resist pattern obtained on the substrate after development processing has become a major issue. That is, as the circuit pattern becomes finer, the resist pattern becomes thinner and the line width becomes thinner, making it more difficult to improve the in-plane uniformity. Moreover, photolithography includes basic steps of resist coating, exposure, and development, and also includes pre-processing and post-processing steps such as baking between these basic steps. If the in-plane uniformity is low, this limits the in-plane uniformity of the film thickness and line width of the resist pattern, which is the final process result. This problem becomes more complex and significant when there are multiple processes with low in-plane uniformity of process results.

  Many techniques for improving the in-plane uniformity of each process result have been proposed for this problem. On the other hand, the film thickness or line width of the resist pattern, which is the final process result, is measured at several representative points on the substrate to obtain a deviation (error) from the set value, for example, a pre-baking process prior to the exposure process In the prior art, a method for adjusting the heating temperature for the substrate in accordance with the deviation is also conventionally performed for each region. For this reason, in the baking apparatus, an area division type planar heater is used, or the height of the proximity pins can be independently changed or adjusted on the hot plate. However, such conventional techniques have large hardware restrictions, and the height adjustment of proximity pins requires a lot of adjustment work, while achieving in-plane uniformity is not good. Has become an issue.

  The present invention solves such problems of the prior art, and provides an auxiliary exposure apparatus capable of realizing a significant improvement in film thickness or line width accuracy or in-plane uniformity of a resist pattern after development processing in photolithography. To do.

  The auxiliary exposure apparatus of the present invention irradiates the resist film on the surface of the substrate with ultraviolet rays having a predetermined wavelength separately from the exposure process in which the mask pattern is transferred to the resist film coated on the substrate to be processed in photolithography. An auxiliary exposure apparatus that performs irradiation with an ultraviolet irradiation unit in which a plurality of irradiation areas provided with one or a plurality of light emitting elements emitting ultraviolet light are arranged in a first direction, and for each of the irradiation areas A light emission driving section for supplying a light emission drive current to the light emitting element; and a second crossing the ultraviolet irradiation unit with the first direction with respect to the substrate so that the resist film on the substrate surface is exposed and scanned. A scanning mechanism that moves relative to the direction, and for each of the irradiation areas, through the light emission drive unit, the command value of the light output for the irradiation area and the corresponding value on the substrate An illuminance characteristic acquisition unit that acquires a command value-illuminance characteristic that represents a relationship with the illuminance at the irradiation position, and the illuminance at the irradiation position on the substrate that faces each irradiation area during the exposure scan becomes a target value. An illuminance control unit that controls the light emission driving unit based on the command value-illuminance characteristic for each of the irradiation areas, and the command value-illuminance characteristic of each of the irradiation areas is acquired so as to match or approximate. And a temperature management mechanism for controlling the temperature of each of the irradiation areas to the same or approximate temperature when performing the exposure scanning after that.

  In the above apparatus configuration, the resist on the substrate surface is irradiated with ultraviolet rays having independent light intensities from a plurality of irradiation areas arranged in a line in the second direction of the ultraviolet irradiation unit. The ultraviolet irradiation unit is relatively moved in the first direction on the substrate by the scanning mechanism, so that the entire resist on the substrate surface is scanned for ultraviolet irradiation, that is, exposure scanning.

  During this exposure scan, the illuminance control unit is based on the command value-illuminance characteristics for each irradiation area so that the illuminance at the irradiated position on the substrate facing each irradiation area matches or approximates the target value. To control the light emission drive unit. Here, the command value-illuminance characteristic is a characteristic (function) representing the relationship between the command value of the light output for the irradiation area and the illuminance of the corresponding irradiated position on the substrate, and is acquired in advance by the illuminance characteristic acquisition unit. ing.

  The temperature management mechanism, for each irradiation area, when the illuminance characteristic acquisition unit acquires the command value-illuminance characteristic, and when the illuminance control unit uses the command value-illuminance characteristic during the subsequent exposure scan, The temperature of the irradiation area is controlled to the same or approximate temperature. As a result, it is possible to perform desired auxiliary exposure processing by irradiating the resist on the substrate surface with ultraviolet rays at a set exposure amount at each position on the substrate.

  According to the auxiliary exposure apparatus of the present invention, it is possible to achieve a significant improvement in the accuracy or in-plane uniformity of the resist pattern film thickness or line width after development processing in photolithography by the configuration and operation as described above. it can.

It is a block diagram which shows the structure on the process flow of the in-line system for optical lithography which can apply the auxiliary exposure apparatus of this invention. It is a figure which shows the format which partitions the product area | region on a board | substrate in matrix form in embodiment. It is a figure which shows the mechanism which calculates and maps the measured value of the film thickness (or line width) of a resist pattern for every unit area | region of the matrix division on a board | substrate. It is a figure which shows the mechanism which calculates and maps correction | amendment exposure amount for every unit area | region of the matrix division on a board | substrate. It is a figure which shows the mechanism which calculates and maps the target value of illumination intensity for every unit area | region of the matrix division on a board | substrate. It is a block diagram which shows the structure of the auxiliary exposure apparatus in embodiment. It is a perspective view which shows the structure of the flat flow conveyance part and UV irradiation unit in the said auxiliary exposure apparatus. It is a side view which shows the structure of the flat flow conveyance part and UV irradiation unit in the said auxiliary exposure apparatus. It is a front view which shows the structure of the whole UV irradiation unit in the said auxiliary exposure apparatus, and the structure of the principal part of a cooling mechanism. It is a bottom view which shows the arrangement configuration of the irradiation area and light emitting element in the linear irradiation part of the said UV irradiation unit. It is a block diagram which shows the whole structure of the cooling mechanism in the said auxiliary exposure apparatus. It is a figure which shows the structure of the irradiation area temperature control part in the said cooling mechanism. It is a block diagram which shows the structure of the light emission drive part in the said auxiliary exposure apparatus, and an illumination intensity measurement part. It is a partially exploded front view which shows the structure of the illumination meter moving mechanism in the said auxiliary exposure apparatus. It is a graph which shows an example (linear function) of command value-illuminance characteristics. It is a figure which shows the mechanism which stores the attribute data of command value-illuminance characteristic on the table of a memory. It is a figure which shows the mechanism which calculates and maps instruction | command value for every unit area | region of the matrix division on a board | substrate. It is a schematic plan view which shows the scan between the board | substrate and UV irradiation unit in the auxiliary exposure process of embodiment. It is a schematic plan view which shows the effect | action of the auxiliary exposure process of embodiment. It is sectional drawing which shows the modification of a cooling mechanism. It is a figure which shows the arrangement configuration of the irradiation area and each cooling plate in the modification of FIG. It is a front view which shows another modification of a cooling mechanism. It is an enlarged front view which shows the structure in 1 group in the modification of FIG.

The preferred embodiments of the present invention will be described below with reference to the accompanying drawings.
[Configuration of substrate processing system]

  FIG. 1 shows a process flow configuration of a substrate processing apparatus to which the auxiliary exposure apparatus of the present invention can be applied in photolithography. This substrate processing apparatus is, for example, an in-line system for manufacturing an FPD, and includes a resist coating unit (CT), a mask exposure apparatus (EXP), and a developing unit (DEP) as basic components. The mask exposure apparatus (EXP) is a normal (regular) exposure apparatus for transferring a photomask pattern to a resist on a substrate to be processed G made of glass, for example.

  Furthermore, this substrate processing apparatus also includes a vacuum drying unit (DP), a pre-bake unit (PRB), and a cooling unit (COL) as standard equipment. The reduced-pressure drying unit (DP) exposes the substrate G immediately after the resist is applied by the resist coating unit (CT) in a reduced-pressure atmosphere for a certain time to evaporate the solvent contained in the resist to a certain stage. The pre-bake unit (PRB) heats the substrate G at a constant temperature before the mask exposure process to evaporate the residual solvent in the resist and improve the adhesion between the resist and the base film. The cooling unit (COL) cools the substrate G to the reference temperature immediately after the pre-baking process.

  The auxiliary exposure apparatus (AE) 10 of the present invention is disposed, for example, between a vacuum drying unit (DP) and a pre-bake unit (PRB) in the process flow. In this case, in the auxiliary exposure apparatus (AE) 10, the accuracy or in-plane uniformity of the film thickness (or line width) of the resist pattern obtained after the development processing is applied to the resist on which the solvent on the substrate G still remains. A special auxiliary exposure process as described later is performed for improvement.

  The substrate processing apparatus includes a resist pattern inspection unit 12, an input unit 14, and an arithmetic processing unit 16 in order to give information or data necessary for the auxiliary exposure process to the auxiliary exposure apparatus (AE) 10. The resist pattern inspection unit 12 was obtained on the sample substrate G after the development processing by the development unit (DEP) (usually after the heat treatment by the post bake unit not shown in the subsequent stage). The film thickness (or line width) of the resist pattern is measured at several representative points (for example, several tens of points) on the substrate G, for example.

  The arithmetic processing unit 16 includes a microcomputer including a memory and various interfaces, and has various functions of an interpolation unit 18, a corrected exposure amount calculating unit 20, and an irradiation map creating unit 22. The input unit 14 includes, for example, a keyboard, a mouse, a touch panel, and the like. Various conditions input by an administrator or an operator to each unit in the system, particularly the arithmetic processing unit 16 and the auxiliary exposure apparatus (AE) 10, Gives set value data such as initial values.

The interpolating unit 18 determines the film thickness (or line width) of the resist pattern based on the measured value at the representative point on the substrate G acquired by the resist pattern inspecting unit 12 by performing a predetermined interpolation process. Calculate the measured value (exactly estimated value) at the position or area. In this embodiment, as shown in FIG. 2A, the product area PA on the substrate G is partitioned in a matrix, and the film thickness (or line width) of the resist pattern is measured for each unit area (i, j) of the matrix section. A value (or an estimated value obtained by the interpolation process) A _{i, j} is calculated and mapped, for example, on a table constructed in the memory as shown in FIG. 2B. In the drawing, in order to facilitate understanding and illustration, the matrix sections are shown by 9 columns (j = 1 to 9). Actually, both the number of rows and the number of columns of the matrix section are at least several tens or more, and a large substrate for FPD has one hundred or more.

The corrected exposure amount calculation unit 20 calculates a corrected exposure amount B _{i, j} for each unit area (i, j) of the matrix section on the substrate G, and displays the result shown in FIG. Map as shown. Here, the corrected exposure amount B _{i, j} is used to bring the difference (error) between the measured value and the set value close to zero with respect to the film thickness (or line width) of the resist pattern in each unit region (i, j). Exposure amount.

  When the resist used in the substrate processing apparatus is, for example, a positive type, the change in the resist pattern thickness and line width increases as the exposure amount increases at each position on the substrate G, and the resist decreases as the exposure amount decreases. Changes in pattern thickness and line width are reduced. In this substrate processing apparatus, a normal mask exposure process by a mask exposure apparatus (EXP) and an auxiliary exposure process by an auxiliary exposure apparatus (AE) 10 are performed in a multiplexed manner. Therefore, in the normal mask exposure process in the mask exposure apparatus (EXP), it is also preferable to set the exposure amount smaller than in the case where the auxiliary exposure process is not performed in anticipation of the auxiliary exposure process by the auxiliary exposure apparatus (AE) 10. .

The irradiation map creation unit 22 calculates the illuminance target value C _{i, j} for each unit area (i, j) of the matrix section on the substrate G, and displays the result shown in FIG. 2D on the table constructed in the memory, for example. Map as shown. Here, if the ultraviolet irradiation time per unit area (i, j) of the matrix section in the auxiliary exposure apparatus (AE) 10 is t _S , C _{i, j} = B _{i, j} / t _S.

[Configuration and operation of auxiliary exposure apparatus]

  FIG. 3 shows the configuration of an auxiliary exposure apparatus (AE) 10 in one embodiment of the present invention. The auxiliary exposure apparatus (AE) 10 has a hardware configuration in which the substrate G is transported in one horizontal direction (X direction) in a fixed posture (for example, a posture on the back), and the flat flow. A UV irradiation unit 32 for irradiating the resist on the substrate G transported by the transport unit 30 with ultraviolet rays (UV) of a predetermined wavelength, and a light emission drive unit for supplying a drive current for light emission to the light emitting elements in the UV irradiation unit 32 34, a cooling mechanism 36 that cools the light emitting elements in the UV irradiation unit 32 to a set temperature, an illuminance measuring unit 38 that measures the illuminance of ultraviolet irradiation by the UV irradiation unit 32, and each part in the apparatus (particularly a flat flow transport unit) 30, the light emission drive unit 34, the cooling mechanism 36, the illuminance measurement unit 38), and the storage unit 40 stores and stores various programs and data used in the control unit 40. That and a memory 42. The control unit 40 is composed of a microcomputer, and executes various required arithmetic processing and control described later according to a predetermined program.

  The flat flow transport unit 30 includes, for example, a roller transport path 46 formed by laying a large number of rollers 44 in the transport direction (X direction), and each roller in order to transport the substrate G in a supine posture on the roller transport path 46. 44 includes a scanning drive unit 50 that rotationally drives 44 via a transmission mechanism 48 having, for example, a belt, a gear, and the like. The roller transport path 46 is connected to the transport system of the front-rear pressure-reducing and drying unit (DP) and the transport system of the rear-next pre-baking unit (PRB) in the process flow (FIG. 1). The flat flow transport unit 30 flatly flows the substrate G that has been subjected to the vacuum drying process in the vacuum drying unit (DP), and carries the substrate G into the auxiliary exposure apparatus (AE) 10, and assists in the auxiliary exposure apparatus (AE) 10. The substrate G is transported in a flat flow for scanning of the exposure process, and the substrate G that has finished the auxiliary exposure process is transported in a flat flow to the pre-paque unit (PRB). The control unit 40 can detect or grasp the current position of the substrate G through position sensors (not shown) arranged in places on the roller conveyance path 46.

  As shown in FIGS. 4 and 5, the UV irradiation unit 32 is provided in the middle of the roller conveyance path 46. The UV irradiation unit 32 is configured as a long unit extending straight in the horizontal direction (Y direction) orthogonal to the substrate transport direction (X direction), and the line irradiation unit (54) faces downward as will be described later. And disposed above the roller conveyance path 46. Although not shown, it is possible to provide an elevating mechanism for adjusting the height position of the UV irradiation unit 32.

  FIG. 6 shows the overall configuration of the UV irradiation unit 32 and the configuration of the main part of the cooling mechanism 36. The UV irradiation unit 32 includes a line-shaped irradiation unit 54 in which a large number of surface-mounted ultraviolet light emitting elements such as LED elements are attached to a lower surface 52a of a single support plate 52 that extends straight in the unit longitudinal direction (Y direction). Have. The support plate 52 is made of a metal having a high thermal conductivity, such as aluminum.

As shown in FIG. 7, the line irradiation unit 54 of the UV irradiation unit 32 includes a plurality (nine) of irradiation areas SE ₁ , SE ₂ , SE ₃ ,... Along the longitudinal direction (Y direction) of the support plate 52. .., divided into SE ₉ The number of area divisions (nine) corresponds to the number of matrix division columns (nine) set in the product area PA of the substrate G, and the nth irradiation area SE _n (n = 1 to 9) is the substrate G. It faces the nth column of the upper matrix section.

In each irradiation area SE _n , one or plural (six in the illustrated example) LED elements J ₁ , J ₂ ,... J ₆ are arranged in one or plural columns (two in the illustrated example). Has been placed. A set of LED elements J ₁ , J ₂ ,... J ₆ provided in each irradiation area SE _n are electrically connected in series as will be described later with reference to FIG. emitted simultaneously by a common drive current I _n, so as to irradiate the ultraviolet rays having a predetermined wavelength to the resist of the substrate G surface passes immediately below the illumination area SE _n (n-th column and the surrounding matrix zone) ing.

As shown in FIG. 6, below the line-shaped irradiation unit 54, a long diffusion plate 56 for expanding the irradiation angle of each irradiation area SE _n is arranged in parallel. A plurality (9 pieces) of plate-like Peltier modules PM _{1 to} PM ₉ are attached to the back side of the line-shaped irradiation unit 54, that is, the upper surface of the support plate 52, in a horizontal row. Each Peltier module PM _n is located behind (directly above) the corresponding irradiation area SE _n , and its support surface 52 sandwiches its cooling surface (heat absorption surface) with, for example, a platinum resistance temperature detector 58 (n). It is affixed to the top surface. A fin-shaped heat sink 60 is coupled to the upper surface of the Peltier modules PM _{1 to} PM ₉ , that is, a heat radiating surface, and a cooling fan 62 is disposed above the heat sink 60.

As shown in FIG. 8, the cooling mechanism 36 includes a pair of Peltier modules PM _n , a resistance temperature detector 58 (n), and an irradiation area temperature control unit 64 (n) for each irradiation area SE _n. Yes. As shown in FIG. 9, the irradiation area temperature control unit 64 (n) includes a bridge circuit 66, a differential amplifier circuit 68, a comparator 70, and a Peltier drive circuit 72.

The bridge circuit 66 and the differential amplifier circuit 68 take out the resistance change of the resistance temperature detector 58 (n) corresponding to the current temperature T as a voltage signal. The comparator 70 compares the voltage signal (temperature detection signal) MT from the differential amplifier circuit 68 with the reference signal ST _n indicating the set temperature T _n from the control unit 40, and generates a comparison error δT _n . The Peltier drive circuit 72 supplies a drive current to the Peltier module PM _n by, for example, a PWM drive method so that the comparison error δT _n becomes zero. The Peltier module PM _n is formed by alternately joining a p-type semiconductor and an n-type semiconductor in series via electrodes. When a current flows, the Peltier module PM _n is opposite to the cooling surface (heat absorption surface) by the Peltier effect. Heat moves to the surface (heat dissipation surface). As a result, the irradiation area SE _n (particularly the LED elements J ₁ , J ₂ ,... J ₆ ) thermally coupled to the cooling surface of the Peltier module PM _n via the support plate 52 is cooled.

The set temperature T _n is a reference value for keeping the temperature of each irradiation area SE _n (particularly the temperatures of the LED elements J ₁ , J ₂ ,... J ₆ ) at a set value. Normally, for all the irradiation areas SE _{1 to} SE ₉ , the set temperatures T _{1 to} T ₉ are selected to be common (identical) values, and the ambient temperature, that is, a temperature somewhat lower than room temperature (preferably only a few degrees C), for example, It is selected from 20 ° C to 22 ° C. However, among the illumination area SE ₁ ~SE ₉ may be different from each set temperature T ₁ through T _9.

As will be described later, when the scanning speed is increased in order to increase the throughput of the auxiliary exposure processing, the exposure time is shortened, and a desired corrected exposure amount can be obtained at each position on the substrate G facing each irradiation area SE _n . The required illuminance is high. Therefore, light emission intensity and thus the driving current I _n is increased is set for each illumination area SE _n. However, an LED element is a semiconductor element that significantly increases the amount of heat generated when the drive current is large and is sensitive to heat, and its light output (irradiance) becomes unstable if heat dissipation is not performed quickly and efficiently. Prone.

In this embodiment, as will be described later, all the irradiation areas SE _{1 to} SE ₉ are driven to emit light independently by the light emission drive unit 34, and the respective irradiance is controlled independently. As described above, the cooling mechanism 36 includes a pair of Peltier modules PM _n , a resistance temperature detector 58 (n), and an irradiation area temperature control unit 64 (n) for each irradiation area SE _n. A passive cooling operation is performed for each irradiation area SE _n so as to increase the cooling in the irradiation area with a high irradiance and weaken the cooling in the irradiation area with a low irradiance. Therefore, the active (open loop) cooling control (forced cooling) in which the temperature sensor (resistance temperature detector) is not mounted is not preferable here. This is because not only when all the irradiation areas SE _{1 to} SE ₉ are uniformly cooled, but also when each of the irradiation areas SE _n is individually cooled, for example, if active cooling (forced cooling) of 15 ° C. or less is performed. This is because, in the irradiation area with low illuminance, the LED temperature becomes too low and a time delay occurs until the illuminance is stabilized.

In this embodiment, even if the scanning speed is set high in order to increase the throughput of the auxiliary exposure processing, or even if the irradiance is greatly different between the irradiation areas, from the end of the line irradiation unit 54 to the end, That is, the temperatures of all the irradiation areas SE _{1 to} SE ₉ can be stably and accurately maintained at the respective set temperatures T _{1 to} T ₉ . This is very important in performing exposure amount correction processing using individual command value-illuminance characteristics for each irradiation area SE _{n as} will be described later.

FIG. 10 shows the configuration of the light emission drive unit 34 and the illuminance measurement unit 38. The light emission drive unit 34 includes an LED driver 74 (n) for each irradiation area SE _n . A set of LED elements J ₁ , J ₂ ,... J ₆ provided in each irradiation area SE _n is electrically connected in series to constitute a load circuit of the LED driver 74 (n). Control unit 40 outputs the digital signal DV _n voltage values displayed as the command value V _n of the light output for each illumination area SE _n of. The digital signal DV _n digital - are converted to analog converter (DAC) by 76 (n) into an analog voltage signal AV _n, the analog voltage signal AV _n is applied to the LED driver 74 (n). LED driver 74 (n) has a constant current source circuit, LED of the illumination area SE _n the drive current I _n corresponding to the command value (voltage signal) V _n from the control unit 40 with a constant current elements J _1, J _2, and supplies the · · J _6. Thus, it LED elements _{J 1, J 2, ·· J} 6 is driven to emit light by the same or a common drive current I _n, emits ultraviolet light of a predetermined wavelength.

In general, LED elements are accompanied by individual differences and changes over time. For this reason, even if the same drive current is supplied, the light outputs of the individual LED elements J ₁ , J ₂ ,... J ₆ are different within each irradiation area SE _n , and their combined outputs also change over time. However, it is not rare that the irradiance or the irradiation intensity varies between the irradiation areas SE _{1 to} SE ₉ .

  In this embodiment, in view of the characteristics of such LED elements, the illuminance measurement unit 38 is provided, and the control unit 40 periodically performs an illuminance characteristic acquisition operation as described later through the light emission drive unit 34 and the illuminance measurement unit 38. I am trying to do it.

  The illuminance measuring unit 38 includes an illuminance meter 80 for measuring the illuminance of ultraviolet rays, and an illuminance meter moving mechanism 82 for moving the illuminance meter 80 in the irradiation line direction (Y direction) directly below the UV irradiation unit 32. I have. The illuminance meter 80 has a photoelectric conversion element such as a photodiode in the vicinity of the top 80a, and generates an electric signal (illuminance measurement signal) ML corresponding to the light intensity of ultraviolet light incident on the light receiving surface. Yes. The illuminance measurement signal ML output from the illuminometer 80 is sent to the control unit 40 via an analog-digital converter (ADC) 84.

  As shown in FIG. 11, the illuminometer moving mechanism 82 moves the illuminometer 80 to the carriage 86 so that the light receiving portion 80 a of the illuminometer 80 is at the same height as the surface of the substrate G when moving on the roller transport path 46. The carriage 86 and the illuminance meter 80 are arbitrarily moved in both directions by a linear motor (not shown), for example, on a rail 88 that is mounted on the rail 88 and extends parallel to the UV irradiation unit 32 (Y direction). The illuminometer 80 can be stopped or stopped at the position. The external wiring (electric cable) of the illuminance meter 80 is accommodated in the cable bear 90. The UV irradiation unit 32 and the rail 88 are provided in the middle of the adjacent rollers 44, and the carriage 86 and the illuminance meter 80 are retracted outside (side) the roller conveyance path 46 when the illuminance characteristic acquisition operation is not performed. It is like that.

  Here, the illuminance characteristic acquisition operation in this embodiment will be described. This illuminance characteristic acquisition operation is performed periodically, for example, every certain device operating time or every certain month and day. The control unit 40 stops the flat flow conveyance unit 30 (with no substrate G on the roller conveyance path 46), and controls each unit of the light emission drive unit 34, the cooling mechanism 36, and the illuminance measurement unit 38 and the entire sequence. To do.

The cooling mechanism 36 operates under the control of the control unit 40 in exactly the same way as when auxiliary exposure processing is performed. That is, the cooling mechanism 36 keeps the temperatures of the irradiation areas SE _{1 to} SE ₉ of the UV irradiation unit 32 at the set temperatures T _{1 to} T ₉ according to the reference signals ST _{1 to} ST ₉ from the control unit 40. Perform passive cooling. As described above, the set temperatures T _{1 to} T ₉ may be normally selected to be the same value.

On the other hand, the light emission drive unit 34 and the illuminance measurement unit 38 operate in cooperation as follows under the control of the control unit 40. In other words, the light emission drive unit 34 first performs light emission driving only on the first irradiation area SE ₁ with a predetermined driving current. In accordance with this, the illuminance measurement unit 38 moves the illuminance meter 80 to a position immediately below the first irradiation area SE ₁ . The illuminometer 80 outputs an illuminance measurement signal ML at each position. The control unit 40 monitors the illuminance measurement signal ML from the illuminometer 80 while finely moving the illuminometer 80 back and forth in the line direction (Y direction), and has the highest illuminance in the vicinity immediately below the first irradiation area SE _1. A high position (peak position) P ₁ is determined, and the position of the illuminometer 80 is adjusted to this peak position P ₁ .

Next, the control unit 40 sequentially gives light emission output command values V _1-1 , V _1-2 ,... V _1-m to the light emission drive unit 34 (m is an integer of 2 or more), and emits the light emission. The illuminance measurement signal ML sequentially output from the illuminometer 80 corresponding to the output command values V _1-1 , V _1-2 ,... V _1-m is taken in, and the illuminance measurement value L ₁₋ at the peak position P ₁ is acquired. ₁ , L _1-2 ,... L _1-m is obtained. Then, the light emitting output command value _{V 1-1, V 1-2, ·· V} 1-m and the measured illuminance value L _1-1, L _1-2, plots and · · L _1-m on the graph For example, a linear function command value-illuminance characteristic α ₁ (when n = 1) as shown in FIG. 12 is acquired. This command value-illuminance characteristic α ₁ is expressed by an equation: α = a ₁ V + b ₁ , where a _{1 is} the slope of the straight line of the linear function and b ₁ is the intercept.

The control unit 40 also repeats the same operation as described above for the _{second to} ninth irradiation areas SE _{2 to} SE ₉ through the light emission drive unit 34 and the illuminance measurement unit 38, and the respective command value-illuminance characteristics α _{2 to} α. _{Get 9}

In this embodiment, in order to enhance the accuracy of the auxiliary exposure process, the area of the n-th column of the matrix partition on the illumination area SE _n and opposing substrates G, adjacent with the illumination area SE _n (e.g. up to one next of) the illumination area _{SE n-1, SE n +} 1 of the command value - illuminance characteristic _{β n-1, γ n +} 1 also together acquires. In that case, the illuminance meter 80 receives each ultraviolet light from the adjacent irradiation areas SE _n-1 and SE _{n + 1} at the first peak position P ₁ immediately below the _first irradiation area SE ₁ and measures the illuminance. To do.

The control unit 40 has predetermined attributes that define the main command value-illuminance characteristic α _n and adjacent command values-illuminance characteristics β _n−1 , γ _{n + 1} acquired for each irradiation area SE _n as described above. Data (tilt, intercept) is stored on a table as shown in FIG. Each time the illuminance characteristic acquisition operation is performed periodically, the table contents are updated by replacing with newly acquired command value-illuminance characteristics α _n , β _n−1 , γ _{n + 1} .

Next, auxiliary exposure processing in this embodiment will be described. When the auxiliary exposure process is performed, not only the light emission drive unit 34 and the cooling mechanism 36 but also the flat flow transport unit 30 operate under the control of the control unit 40. The flat flow transport unit 30 flatly flows the substrate G that has been subjected to the vacuum drying process in the vacuum drying unit (DP), and carries the substrate G into the auxiliary exposure apparatus (AE) 10, and assists in the auxiliary exposure apparatus (AE) 10. The substrate G is transported in a flat flow for scanning exposure processing. Here, the flattening conveyance speed v is a scanning speed in the auxiliary exposure process, and is also related to the ultraviolet irradiation time t _S per unit area (i, j) of the matrix section on the substrate G. That is, if a proportional constant is K, the inverse proportional relation of v = K / t _s.

Prior to the auxiliary exposure processing, the control unit 40 has the irradiation command (FIG. 2D) input from the arithmetic processing unit 16 and the latest command value-illuminance characteristics α _n , β _n−1 , γ held in the table of the memory 42. _With reference to _{n + 1} (FIG. 13), a command value V _{i, j} is calculated for each unit area (i, j) of the matrix section on the substrate G, for example, a table constructed in the memory 42 Mapping is performed as shown in FIG.

Here, each command value V _{i, j} includes the main command value-illuminance characteristic α _j and the adjacent command value-illuminance characteristics β _j−1 , γ _{j + 1} in consideration of the target illuminance C _{i, j.} Determined or selected to obtain. For example, when attention is paid to the unit areas (i, 2) to (i, 9) in the i-th row of the matrix section, the target illuminances C _1,1 to C in the respective unit areas (1, 2) to (1, 9). The command values V _{i, 1 to} V _{i, 9} for the i-th row are determined or selected so that C _1,9 is obtained. For this purpose, for example, command values V _{1,1 to} V _1,9 are used as variables, and illuminances C _{i, 1 to} C _{i, 9} are used as existing values, and command values-illuminance characteristics (primary functions) α _n , β _{n− An} operation for solving simultaneous equations of ₁ and γ _{n + 1} (n = 1, 2,..., 9) is performed. Or, it is suitable for the variables of command value-illuminance characteristics α _n , β _n−1 , γ _{n + 1} (n = 1, 2,..., 9) (each command value V _{1,1 to} V _1,9 ). calculates the illuminance C _{i, 1} -C i, ₉ by fitting the numerical illuminance C _{i, 1} -C i, a method of calculating values of ₉ repeats a predetermined number of times fitting the to respectively approach the desired value suitably adopted It is done.

On the other hand, the control unit 40 causes the cooling mechanism 36 to operate in exactly the same manner as in the illuminance characteristic acquisition operation. That is, as described above, the cooling mechanism 36 is caused to perform a basic cooling operation so as to keep the temperatures of the irradiation areas SE _{1 to} SE ₉ of the UV irradiation unit 32 at the set temperatures T _{1 to} T ₉ , respectively.

Then, as shown in FIG. 15, the control unit 40 causes the substrate G and the UV irradiation unit 32 for auxiliary exposure processing to be scanned through the light emission drive unit 34 and the flat flow transport unit 30. In this scanning, when the unit areas (i, 1) to (i, 9) in the i-th row of the matrix section on the substrate G pass directly under the UV irradiation unit 32, the LED driver 74 ( The command values V _{i, 1 to} V _{i, 9} for the i-th row are given to 1) to 74 (9). Accordingly, the unit areas (i, 1) to (i, 9) in the i-th row are independent of each irradiation area SE _{n in the} line direction (Y direction) from the line-shaped irradiation unit 54 of the UV irradiation unit 32. A belt-shaped ultraviolet ray having a light output is irradiated for a predetermined time at a set illuminance C _{i, 1 to} C _{i, 9} . Here, the irradiation for a fixed time for the i-th row may be either continuous irradiation or pulse irradiation.

Thus, as shown in FIG. 16, when the substrate G passes directly under the UV irradiation unit 32, the illuminance or exposure amount independent for each unit region (i, j) on the irradiation line (each row of the matrix section). Auxiliary exposure is performed. When this auxiliary exposure processing is completed, the substrate G is sequentially sent to a pre-bake unit (PRB), a cooling unit (COL), a mask exposure device (EXP), and a development unit (DEP). As a result, a resist pattern film thickness (or line width) exhibiting desired accuracy and in-plane uniformity is obtained on the substrate G carried out of the developing unit (DEP).

[Other Embodiments or Modifications]

The cooling mechanism 36 of the auxiliary exposure apparatus (AE) 10 in the above-described embodiment includes a pair of Peltier modules PM _n , an illumination area temperature control unit 64 (n), and a measurement for each irradiation area SE _n of the UV irradiation unit 32. resistance temperature (temperature sensor) provided 58 (n), so that the detection temperature T of the measuring resistor 58 (n) matches the set temperature T _n, the lighting area temperature control unit 64 (n) is the closed loop control configured in such a driving current is supplied I _n the Peltier module PM _n.

As a modification, as shown in FIG. 17, each illumination area temperature control is performed so that the temperature of each irradiation area SE _n becomes the set temperature T _n without using the resistance temperature detector (temperature sensor) 58 (n). part 64 (n) that is possible to configure to supply the driving current I _n to the Peltier module PM _n the open-loop control. In this case, each illumination area temperature control unit 64 (n) may be configured by only the Peltier drive circuit 72. However, the control unit 40 applies correction according to the command value V _n to the reference signal ST _n given to each illumination area temperature control unit 64 (n). That is, the command value V _n applied to the LED driver 74 of the light emission drive portion 34 (n) strengthened relatively cool the larger, the correction to the reference signal ST _n to weaken the relatively cool enough command value V _n is small multiply.

Thus, when the cooling mechanism 36 is configured in an open loop control system, it is preferable to reduce temperature interference as much as possible between the adjacent irradiation areas SE _n and SE _{N + 1} . For this purpose, as shown in FIGS. 17 and 18, for example, it is preferable to employ a configuration in which individual support plates 52 (n) and 52 (n + 1) are filled in the irradiation areas SE _n and SE _{N + 1} , respectively. Can do. In this case, each of the support plates 52 (n) and 52 (n + 1) is mounted on a holder 92 made of, for example, resin having low thermal conductivity. Thus, the heat insulation part which prevents temperature interference between the irradiation areas which adjoin each other is applicable also in embodiment of the said closed loop control system.

As another modification of the cooling mechanism 36, for example, as shown in FIGS. 19 and 20, several consecutive irradiation areas SE _n , SE _{N + 1} , SE _{N + 2} are grouped into one group. In addition, a configuration in which one set of Peltier module PM _M , illumination area temperature controller 64 (M), and resistance temperature detector (temperature sensor) 58 (M) can be adopted for each group.

As described above, the number of matrix columns partitioned on the substrate G, that is, the number of irradiation areas SE divided on the UV irradiation unit 32 is generally several tens or more or one hundred or more. Among them, the irradiances set in about several consecutive irradiation areas SE _n , SE _{N + 1} , SE _{N + 2} are approximately approximate and are not extremely different. Accordingly, in the cooling mechanism 36, a set of Peltier modules PM _M , an illumination area temperature control unit 64 (M), and a resistance temperature detector (temperature sensor) 58 (M) provide a continuous or adjacent irradiation area in each group. SE _n , SE _{N + 1} , SE _{N + 2} can be cooled stably and accurately.

  Various other modifications are possible for the cooling mechanism 36. For example, the Peltier module is an optimal cooling means with excellent responsiveness. However, in place of the Peltier module, there is a decrease in responsiveness. For example, a water-cooling cooling means can be used.

As another modification of the cooling mechanism 36, a temperature management mechanism that controls the temperature of each irradiation area SE _n of the UV irradiation unit 32 to a set temperature higher than the ambient temperature (room temperature) can be used.

Various modifications can also be made in the UV irradiation unit 32. In particular, the layout in which the LED elements are arranged in each irradiation area SE _n is arbitrary. For example, a configuration in which a plurality of LED elements are arranged in a staggered manner is also possible.

  The auxiliary exposure apparatus (AE) 10 in the above-described embodiment includes the flat flow transport unit 30 that transports the substrate G by flat flow, and fixes the UV irradiation unit 32 at a fixed position in the scanning direction. However, for example, a scanning method in which the substrate G is fixed to a stage and the UV irradiation unit 32 is moved in the scanning direction on the stage, or a scanning method in which both the substrate G and the UV irradiation unit 32 are moved is possible.

  In the substrate processing apparatus (FIG. 1) in the above embodiment, the auxiliary exposure apparatus (AE) 10 is disposed between the reduced pressure drying unit (DP) and the pre-baking unit (PRB) in the process flow. However, the auxiliary exposure apparatus (AE) 10 can be disposed at any position as long as it is between the resist coating unit (CT) and the development unit (DEP) in the process flow. Therefore, between the pre-bake unit (PRB) and the cooling unit (COL), between the cooling unit (COL) and the mask exposure apparatus (EXP), or between the mask exposure apparatus (EXP) and the development unit (DEP). An auxiliary exposure device (AE) 10 may be arranged.

  Further, the auxiliary exposure apparatus (AE) of the present invention can be applied not only to the case of using a positive type resist but also to an application using a negative type resist. The substrate to be treated in the present invention is not limited to a glass substrate for FPD, and other flat panel display substrates, semiconductor wafers, organic EL, various substrates for solar cells, CD substrates, photomasks, printed substrates, and the like are also possible. .

10 Auxiliary exposure equipment (AE)
DESCRIPTION OF SYMBOLS 12 Resist pattern inspection part 14 Input part 16 Arithmetic processing part 30 Flat flow conveyance part 32 UV irradiation unit SE (1) -SE (9), SE (n) Irradiation area 34 Light emission drive part 36 Cooling mechanism 38 Illuminance measurement part 40 Control Unit 42 Memory 50 Scanning drive unit 52 Support plate 54 Line-shaped irradiation unit 56 Diffusion plate 58 (1) to 58 (9), 58 (n) Resistance temperature detector (temperature sensor)
PM (1) to PM (9), PM (n) Peltier module 60 Heat sink 64 (1) to 64 (9), 64 (n) Irradiation area temperature controller 74 (1) to 74 (9), 74 (n ) LED driver 80 Illuminance meter 82 Illuminance meter moving mechanism

Claims (15)

In photolithography, an auxiliary exposure apparatus for irradiating the resist film on the surface of the substrate with ultraviolet rays of a predetermined wavelength separately from the exposure process for transferring a mask pattern to a resist film applied on a substrate to be processed,
An ultraviolet irradiation unit in which a plurality of irradiation areas provided with one or a plurality of light emitting elements emitting ultraviolet light are arranged in a first direction;
A light emission drive unit for supplying a drive current for light emission to the light emitting element for each of the irradiation areas;
A scanning mechanism for moving the ultraviolet irradiation unit relative to the substrate in a second direction intersecting the first direction so as to expose and scan the resist film on the substrate surface;
For each of the irradiation areas, through the light emission drive unit, an illuminance characteristic acquisition for acquiring a command value-illuminance characteristic indicating a relationship between a command value of light output for the irradiation area and the illuminance of a corresponding irradiated position on the substrate And
Based on the command value-illuminance characteristic for each irradiation area so that the illuminance at the irradiated position on the substrate facing the irradiation area matches or approximates a target value during the exposure scanning. An illuminance control unit for controlling the light emission drive unit;
A temperature management mechanism that controls the temperature of each irradiation area to the same or approximate temperature when the command value-illuminance characteristic is acquired for each of the irradiation areas and when the exposure scanning is performed thereafter. Auxiliary exposure apparatus having. The light emitting element is a surface mount type LED element,
The ultraviolet irradiation unit has the LED element attached to a support member having high thermal conductivity in each of the irradiation areas.
The auxiliary exposure apparatus according to claim 1.   The auxiliary exposure apparatus according to claim 2, wherein the temperature management mechanism includes a cooling mechanism coupled to the support member. The cooling mechanism is
A Peltier module attached to the support member with the cooling surface facing;
A heat sink connected to the heat dissipation surface of the Peltier module;
The auxiliary exposure apparatus according to claim 3, further comprising: an illumination area temperature control unit that supplies a predetermined current to the Peltier module by constant current control.   The auxiliary exposure apparatus according to claim 4, wherein the Peltier module and the illumination area temperature control unit are provided for each of the irradiation areas.   For each irradiation area, a temperature sensor is individually attached to the support member, and the illumination area temperature control unit supplies a drive current to the Peltier module so that the temperature detected by the temperature sensor matches the set temperature. The auxiliary exposure apparatus according to claim 5.   The auxiliary exposure apparatus according to claim 5, wherein the illumination area temperature control unit supplies a drive current corresponding to the command value to the Peltier module for each of the irradiation areas.   The auxiliary exposure apparatus according to any one of claims 5 to 7, further comprising a heat insulating portion for preventing thermal mutual interference between the two adjacent irradiation areas.   The auxiliary exposure apparatus according to claim 4, wherein all the irradiation areas are grouped into a plurality of groups along the arrangement direction, and the Peltier module and the illumination area temperature control unit are provided for each group.   For each group, a temperature sensor is individually attached to the support member, and the lighting area temperature control unit supplies a drive current to the Peltier module so that the temperature detected by the temperature sensor matches a set temperature. The auxiliary exposure apparatus according to claim 9.   The auxiliary exposure apparatus according to claim 9 or 10, further comprising a heat insulating portion for preventing thermal mutual interference between two adjacent groups. The illuminance characteristic acquisition unit
The ultraviolet rays emitted from the irradiation areas according to a predetermined command value at the same height position as the surface of the substrate when the ultraviolet rays are irradiated from the irradiation areas during the exposure scanning. A photoelectric conversion element that receives light and outputs a signal indicating the light intensity;
An illuminance measurement unit for obtaining a measurement value of illuminance based on an output signal of the photoelectric conversion element;
A function determining unit that plots a plurality of the command values and the illuminance measurement values corresponding to each of the command values and determines a function that applies to the command value-illuminance characteristics, according to any one of claims 1 to 11. Auxiliary exposure apparatus as described.   13. The auxiliary exposure apparatus according to claim 1, wherein the scanning mechanism includes a flat-flow-type substrate transport unit that transports the substrate in a supine posture at a constant speed in the second direction. .   Product regions on the substrate are partitioned in a matrix, the row direction and the column direction of the matrix correspond to the first and second directions, respectively, and each column of the matrix is set to each of the ultraviolet irradiation units. 14. The auxiliary exposure apparatus according to claim 1, wherein the illuminance target value is set for each unit region of the matrix so as to face the irradiation area in a one-to-one correspondence relationship.   The illuminance target value is set on the basis of an error between a measured value of a resist pattern after development processing or a line width measured at each position on the substrate or an estimated value by interpolation and a set value. Auxiliary exposure apparatus as described.

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