JP2590709C - - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoresist oven, and more particularly to an oven for forming a fine pattern having a large thickness using a liquid photoresist. [0002] Conventionally, as a heating method of a photoresist baking oven, there are a hot air circulation system, a hot plate system, a belt furnace system, and a multi-stage hot plate system. The hot air circulation method is a method in which a constant temperature gas is circulated between a box-shaped chamber provided with a door for taking in and out a substrate and a hot air generating mechanism, and the substrate in the chamber is baked with the constant temperature gas. [0004] The hot plate method is a method in which a substrate is placed on a heating plate (hot plate) heated to a constant temperature and the heat of the heating plate is conducted to the substrate to bake the substrate. In the belt furnace type, a substrate-conveying belt is rotated through a square tubular pipe, and a plurality of locations of the pipe are heated from the outside to bring the inside of the pipe to an intended temperature state. Thereafter, the substrate is baked while the substrate is placed on a belt and moved in a pipeline. In the multi-stage hot plate system, a plurality of heating plates (hot plates) heated to a constant temperature are arranged, and the heating plates are connected to each other by a transfer machine. In this method, the substrate is baked so as to move every time. In this method, each heating plate is usually set to a different temperature. [0007] In the above-described conventional heating method in a photoresist baking oven, the substrate is heated in an atmosphere or a heating plate maintained at a uniform temperature. In addition, the temperature rise at the outer peripheral portion of the substrate is fast, and a temperature rise difference between the outer peripheral portion of the substrate and the central portion of the substrate is inevitable. Further, the baking state of each substrate is not constant due to variations in the material or dimensions of the substrate on which the photoresist is formed. For these reasons,
The baking state of the photoresist becomes uneven, and the pattern shape is disturbed.
Further, since the solvent evaporates faster on the photoresist surface than on the inside of the photoresist, the solvent remains in the photoresist, causing a difference in the developing speed of the photoresist and deteriorating the shape of the cross section of the pattern. Accordingly, an object of the present invention is to solve the above-mentioned problems, to eliminate the temperature rise difference between the outer peripheral portion of the substrate and the central portion of the substrate, and to prevent the pattern shape of the photoresist from being disturbed. To provide a photoresist oven that can be used.
It is another object of the present invention to provide a photoresist oven that can eliminate unevenness in the baking state between substrates and can prevent pattern shape disorder. Still another object of the present invention is to provide a photoresist oven capable of suppressing the residual amount of the solvent inside the photoresist to a predetermined concentration or less and preventing the pattern cross-sectional shape from being deteriorated. It is in. A photoresist oven according to the present invention is a photoresist oven used in a photolithography process in the manufacture of a substrate, wherein the substrate is placed at least in an outer peripheral portion and a central portion. A plurality of heating plates for dividing and heating, a heating controller for independently controlling the temperature of each of the plurality of heating plates, a temperature sensor for detecting the temperature of each of the plurality of heating plates, and detection of the temperature sensor A heating feedback mechanism for calculating a correction value for correcting the thermal coupling relationship between each of the plurality of heating plates based on the result and outputting the correction value to the heating controller, and supplying and exhausting the substrate to the atmosphere. A supply / exhaust controller for reducing the concentration of the photoresist-containing solvent in the atmosphere of the substrate, and a photoresist in the atmosphere of the substrate. A concentration sensor for detecting the concentration of the contained solvent, and a supply value for calculating a correction value for correcting the supply / exhaust amount to the atmosphere of the substrate based on the detection result of the concentration sensor and outputting the correction value to the supply / exhaust controller. An exhaust control feedback mechanism, a solvent supply device for supplying a vapor of a main component of the photoresist-containing solvent into the atmosphere of the substrate to increase the concentration of the photoresist-containing solvent, and based on a detection result of the concentration sensor. A solvent supply feedback mechanism that calculates a correction value for correcting the supply amount of the vapor of the main component of the photoresist-containing solvent and outputs the correction value to the solvent supply device, and the photoresist-containing mechanism in the atmosphere of the substrate. After the concentration of the solvent reaches a predetermined concentration, the temperature of each of the plurality of heating plates is controlled by the heating controller and the heating feedback mechanism. The concentration of the photoresist-containing solvent in the atmosphere of the substrate is reduced after the substrate is heated by the heating plate by the supply / exhaust regulator and the supply / exhaust adjustment feedback mechanism, and the solvent supply device and the solvent supply feedback mechanism. I am trying to adjust it. Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, a substrate 20 coated with a photoresist 21 is placed in a baking chamber 18 with a door 19 for taking in and out the substrate. A hot air circulation duct 16 is connected to the baking chamber 18, and the atmosphere in the baking chamber 18 is circulated by the circulation fan 17 using the hot air circulation duct 16 as a circulation path. The baking chamber 18 has nine heating plates 1a to 1a.
i (heating plates 1 d to 1 i are not shown) are provided, and the substrate 20 is set on the heating plates 1 a to 1 i via the temperature sensor 3. The heating of the heating plates 1a to 1i is controlled by a heater 2 comprising corresponding heating controllers 2a to 2i (heating controllers 2d to 2i are not shown). A predetermined time-series heating program is executed by the heater 2, and the temperature rise in each of the outer peripheral portion and the central portion of the substrate 20 is individually controlled. That is, the heating control of the heating plates 1a to 1i by the heating controllers 2a to 2i is performed independently so that the temperature rise at the outer peripheral portion of the substrate 20 is slower than the temperature rise at the central portion. The difference in temperature rise between the outer peripheral portion and the central portion of the substrate 20 can be eliminated. Here, the heating program executed in the heater 2 can be set by an external signal. The temperature sensors 3 are provided corresponding to the respective heating plates 1a to 1i, and send out the temperatures detected by the respective heating plates 1a to 1i to the temperature detector 4.
The temperature detector 4 has a converter for signal output and a display unit, and outputs a detection signal to the heating feedback mechanism 5. The heating feedback mechanism 5 calculates a deviation between a built-in heating program and a detection signal from the temperature detector 4 and performs an operation for correcting the thermal coupling relationship between the heating plates 1a to 1i. Here, the thermal coupling relationship between the heating plates 1a to 1i means that when one of the heating plates 1a to 1i is heated, the heat is applied to the adjacent heating plate 1a.
The relationship transmitted to the heating plates 1a to 1i and affecting the heating control of the heating plates 1a to 1i is shown. Therefore, when one of the heating plates 1a to 1i is heated, a curve of the temperature rise in the adjacent heating plates 1a to 1i is calculated in advance by an experiment or the like, and the heating plate is calculated based on this curve. Correction of the thermal coupling relationship between 1a to 1i is performed. The heating feedback mechanism 5 sends the result of the calculation to each of the heating regulators 2a to 2i in the heater 2, and controls the heating of each of the heating plates 1a to 1i. Each of the density sensors 6a to 6c is a photo resist 2 in a circulating atmosphere.
1 is set to the circulation suction side of the baking chamber 18 and the baking chamber 18.
The density is detected in the inside and on the discharge side of the baking chamber 18 and the detected density is sent to the density detector 7. The density detector 7 has a converter for signal output and a display unit, and the photoresist detected on the circulation suction side of the baking chamber 18, the inside of the baking chamber 18 and the discharge side of the baking chamber 18, respectively. The solvent concentration 21 is output as a detection signal to the supply / exhaust control feedback mechanism 8 and the solvent supply feedback mechanism 9. The air supply / exhaust controller 10 includes an exhaust unit 11, a circulating pressure difference generating unit 12, a fresh gas supply unit 13, and an adjusting unit 14 inside, and the concentration of the solvent evaporated from the photoresist 21 in the circulating atmosphere. To achieve the reduction function. The circulating pressure difference generating section 12 is driven by the control of the adjusting section 14, and operates so as to separate a side for sucking air or inert gas into the circulating atmosphere and a side for discharging the circulating atmosphere. The fresh gas supply unit 13 takes in air or an inert gas from the outside, and supplies the air or the inert gas into the atmosphere circulating through the hot air circulation duct 16. When a predetermined time-series concentration program is executed by the supply / exhaust controller 10, the solvent concentration of the photoresist 21 in the circulating atmosphere decreases. That is, the circulating pressure difference generating section 12 separates the side into which air or inert gas is sucked and the side into which the circulating atmosphere is exhausted, the exhaust section 11 exhausts the circulating atmosphere, and the fresh gas supply section 13 sets the By supplying air or an inert gas, the solvent concentration of the photoresist 21 in the circulating atmosphere decreases. Here, the supply / exhaust controller 10
Can be set by an external signal. The feed / exhaust adjustment feedback mechanism 8 calculates a correction signal for correcting a deviation between a built-in concentration program and a detection signal from the concentration detector 7, and sends the correction signal to the supply / exhaust adjuster 10. The solvent concentration of the photoresist 21 in the circulating atmosphere is controlled. The solvent supply unit 15 includes a vapor generating section 15a for a main component of the photoresist-containing solvent and an adjusting section 15b for controlling the amount of vapor generated in the vapor generating section 15a. The function of increasing the concentration of the evaporated solvent is realized. When a predetermined time-series concentration program is executed by the solvent supply device 15, the solvent concentration of the photoresist 21 in the circulating atmosphere increases. That is,
The vapor generation unit 15a is driven by the control of the adjustment unit 15b, and the vapor of the main component of the photoresist-containing solvent generated in the vapor generation unit 15a is supplied to the circulation atmosphere, and the solvent concentration of the photoresist 21 in the circulation atmosphere increases. . Here, the solvent supply device 1
The density program executed in 5 can be set by an external signal. The solvent supply feedback mechanism 9 calculates a correction signal for correcting a deviation between a built-in concentration program and a detection signal from the concentration detector 7, and sends the correction signal to the solvent supply unit 15 to send the correction signal to the circulation atmosphere. The solvent concentration of the inside photoresist 21 is controlled. In the idle state of the photoresist oven, the atmosphere in the baking chamber 18 is circulated. When the substrate 20 is set in the baking chamber 18 and a program start is instructed to the heating feedback mechanism 5, the supply / exhaust control feedback mechanism 8 and the solvent supply feedback mechanism 9, first, the solvent supply unit 15 supplies the solvent vapor. The generated solvent concentration of the photoresist 21 in the circulating atmosphere is increased to a predetermined concentration. As a result, solvent evaporation from the photoresist 21 on the substrate 20 is suppressed. During this time, the solvent concentration of the photoresist 21 in the circulating atmosphere is maintained at a predetermined concentration by the operation of the solvent supply feedback mechanism 9 based on the detection signal from the concentration detector 7. Next, the heating plates 1a to 1i are controlled by heating control by the heating controllers 2a to 2i.
1i operates, and the substrate 20 is heated. At this time, the temperature rise of the heating plate located at the outer peripheral portion of the substrate 20 is made slower than the temperature rise of the heating plate located at the central portion of the substrate 20. Further, the action of the heating feedback mechanism 5 based on the detection signal from the temperature detector 4 controls the temperature rise of the heating plates 1a to 1i individually. Thereafter, the generation of the solvent vapor by the solvent supply unit 15 is stopped, and then the supply / exhaust air regulator 10 operates to reduce the solvent concentration in the circulating atmosphere according to a predetermined concentration program. At this time, the solvent concentration of the photoresist 21 in the circulating atmosphere is reduced according to a predetermined concentration program by the operation of the air supply / exhaust control feedback mechanism 8 based on the detection signal from the concentration detector 7. As described above, the heating plates 1a to 1i which are divided into nine parts and combined and the heater 2 which can independently control the temperature of each of the heating plates 1a to 1i are provided.
It is possible to individually control at least the temperature rise of each of the outer peripheral portion and the central portion of the substrate 20. Therefore, the difference in temperature rise between the outer peripheral portion and the central portion of the substrate 20 can be eliminated, so that the pattern formation of the photoresist 21 can be prevented from being disordered. Further, a temperature sensor 3 and a temperature detector 4 for detecting the temperature of each of the heating plates 1a to 1i, and a deviation between a detection signal from the temperature detector 4 and a heating program are calculated, and heating is performed to the deviation. The apparatus includes a heating feedback control mechanism 5 that performs an operation for correcting the thermal coupling relationship between the plates 1a to 1i and provides the operation result to the heater 2 to perform feedback control. Heating can be performed. Accordingly, the deviation from the predetermined heating program can be reduced, and the unevenness of the baking state between the substrates 20 can be eliminated, so that the pattern formation of the photoresist 21 can be prevented from being disordered. Further, concentration sensors 6a to 6c and a concentration detector 7 for detecting the solvent concentration of the photoresist 21 on the circulation suction side of the baking chamber 18, the inside of the baking chamber 18, and the discharge side of the baking chamber 18, A correction signal for correcting the deviation between the detection signal from the detector 7 and the density program is calculated and sent to the air supply / exhaust controller 10 to supply and exhaust air for controlling the solvent concentration of the photoresist 21 in the circulating atmosphere. The correction feedback mechanism 8 and a correction signal for correcting the deviation between the detection signal from the concentration detector 7 and the concentration program are calculated and the solvent feeder 1 is calculated.
5 and a solvent supply feedback mechanism 9 for controlling the solvent concentration of the photoresist 21 in the circulating atmosphere, so that the solvent concentration of the photoresist 21 in the atmosphere in the baking chamber 18 is controlled. The solvent evaporation rate on the surface of the photoresist 21 can be suppressed. As a result, the evaporation time of the solvent in the photoresist 21 can be secured, and the amount of the solvent remaining in the photoresist 21 can be reduced to a predetermined concentration or less. Therefore, the difference in the developing speed of the photoresist 21 can be set within an allowable range, and deterioration of the shape of the pattern cross section of the photoresist 21 can be prevented. As described above, according to the photoresist oven of the present invention, the temperature of each of the plurality of heating plates is independently controlled, and the substrate is divided into at least an outer peripheral portion and a central portion. By heating, it is possible to eliminate the temperature rise difference between the outer peripheral portion of the substrate and the central portion of the substrate, and it is possible to prevent the pattern shape of the photoresist from being disordered. According to another photoresist oven of the present invention, the correction value for correcting the thermal coupling relationship between each of the plurality of heating plates based on the temperature detected from each of the plurality of heating plates. By calculating and controlling the temperature of each of the plurality of heating plates in accordance with the correction, it is possible to eliminate the unevenness in the baking state between the substrates and to prevent the pattern shape from being disordered. Further, according to another photoresist oven of the present invention, by adjusting the concentration of the solvent containing the photoresist in the atmosphere of the substrate, the residual amount of the solvent inside the photoresist can be suppressed to a predetermined concentration or less. Thus, there is an effect that deterioration of the shape of the pattern cross section can be prevented.

[Brief description of the drawings] FIG. 1 is a configuration diagram showing one embodiment of the present invention. [Explanation of symbols] 1a-1c heating plate 2 heater 2a ~ 2c Heating regulator 3 Temperature sensor 4 Temperature detector 5 Heating feedback mechanism 6a-6c density sensor 7 Concentration detector 8 Air supply / exhaust control feedback mechanism 9 Solvent supply feedback mechanism 10 Supply and exhaust air regulator 15 Solvent feeder 16 Hot air circulation duct 18 Baking chamber 20 substrates 21 Photoresist

Claims (1)

Claims 1. A photoresist oven used in a photolithography step in the manufacture of a substrate, comprising a plurality of heating units for heating the substrate by dividing the substrate into at least an outer peripheral portion and a central portion. A plate, a heating controller that independently controls the temperature of each of the plurality of heating plates, a temperature sensor that detects a temperature of each of the plurality of heating plates, and a heating sensor based on a detection result of the temperature sensor. A heating feedback mechanism for calculating a correction value for correcting the thermal coupling relationship between the two and outputting the correction value to the heating controller; and supplying and exhausting air to and from the atmosphere of the substrate to form a photoresist in the atmosphere of the substrate. A supply / exhaust controller for reducing the concentration of the solvent, a concentration sensor for detecting the concentration of the photoresist-containing solvent in the atmosphere of the substrate, A supply / exhaust adjustment feedback mechanism that calculates a correction value for correcting the supply / exhaust amount of the substrate into the atmosphere based on the detection result of the sensor and outputs the correction value to the supply / exhaust adjuster; A solvent supply device for supplying a vapor of the main component of the photoresist-containing solvent to increase the concentration of the photoresist-containing solvent, and a supply amount of the main component vapor of the photoresist-containing solvent based on the detection result of the concentration sensor And a solvent supply feedback mechanism that calculates a correction value for correcting and outputs the correction value to the solvent supply device, and the concentration of the photoresist-containing solvent in the atmosphere of the substrate reaches a predetermined concentration.
After that, the temperature of each of the plurality of heating plates is controlled by the heating controller and the heating feedback mechanism, and the supply / exhaust adjustment controller and the supply / exhaust adjustment feedback mechanism, and the solvent supply unit and the solvent supply feedback mechanism, The concentration of the photoresist-containing solvent in the atmosphere of the substrate is determined by the
An oven for photoresist, wherein the oven is adjusted so as to decrease after being heated by the photoresist.