Substrate processing method, substrate processing apparatus, and storage medium

Abstract

Obtaining a resist pattern with good shape using a developing fluid, which is a gas or mist. [Solution] A substrate processing method for developing a resist film containing a metal formed on a substrate by supplying a developing fluid, which is a gas or mist according to the present disclosure, to a substrate, comprising: a first heat treatment step of heat-treating the substrate after the resist film has been exposed along the pattern; a first development step of supplying the developing fluid to the substrate that has undergone the first heat treatment step to remove a portion of the resist film in the depth direction; and a second development step of supplying the developing fluid to the substrate that has undergone the first development step to form the pattern, and removing the region from which the resist film was removed by the first development step in the depth direction up to the development completion position.

Description

Technical Field

[0001] The present disclosure relates to a substrate processing method, a substrate processing apparatus, and a storage medium.

Background Art

[0002] In the manufacturing process of semiconductor devices, for example, after forming a resist film on a substrate such as a semiconductor wafer (hereinafter referred to as a wafer), heating is performed after exposure, and then development is performed to pattern the resist film. Photolithography is included. Patent Document 1 describes forming a resist film containing a tin-based organometallic compound as the above resist film.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides a technique capable of obtaining a resist pattern with a good shape using a developing fluid that is a gas or a mist.

Means for Solving the Problems

[0005] The substrate processing method of the present disclosure is a substrate processing method in which a developing fluid that is a gas or a mist is supplied to a substrate to develop a resist film containing a metal formed on the substrate to form a pattern, a first heat treatment step of heat-treating the substrate after the resist film is exposed along the pattern; a first developing step of supplying the developing fluid to the substrate after the first heat treatment step is performed, and removing a part in the depth direction of the resist film; A second developing step involves supplying the developing fluid to the substrate on which the first developing step has been performed to form the pattern, and removing the region from which the resist film was removed by the first developing step in the depth direction up to the development completion position. It is equipped with. [Effects of the Invention]

[0006] This disclosure shows that a resist pattern with good shape can be obtained using a developing fluid, which is a gas or mist. [Brief explanation of the drawing]

[0007] [Figure 1] This is a plan view of a wafer processing system according to the first embodiment of this disclosure. [Figure 2] This is a longitudinal cross-sectional front view of the wafer processing system. [Figure 3] This is a longitudinal cross-sectional side view showing the resist film developed in the comparative example. [Figure 4] This is a longitudinal cross-sectional side view showing the resist film developed in the comparative example. [Figure 5] This is a longitudinal cross-sectional side view of a developing apparatus provided in the wafer processing system. [Figure 6] This is an explanatory diagram showing the processing steps in the aforementioned developing apparatus. [Figure 7] This is an explanatory diagram showing the processing steps in the aforementioned developing apparatus. [Figure 8] This is an explanatory diagram showing the processing steps in the aforementioned developing apparatus. [Figure 9] This is an explanatory diagram showing the processing steps in the aforementioned developing apparatus. [Figure 10] This chart shows the progression of development reactivity in the aforementioned processing step. [Figure 11] This chart shows the progression of development reactivity in a different processing step. [Figure 12] A longitudinal cross-sectional side view showing the resist film processed by the aforementioned developing apparatus. [Figure 13] This chart shows the trend in development reactivity over time. [Figure 14] It is a chart showing the transition of the development reactivity. [Figure 15] It is a chart showing the transition of the development reactivity. [Figure 16] It is a chart showing the transition of the development reactivity. [Figure 17] It is a longitudinal side view showing the resist film processed by the developing device. [Figure 18] It is a chart showing the transition of the development reactivity. [Figure 19] It is a longitudinal side view showing a configuration example of a developing device that supplies developing mist. [Figure 20] It is a longitudinal side view showing another configuration example of a developing device that supplies developing mist. [Figure 21] It is a longitudinal side view showing another configuration example of a developing device that supplies developing gas. [Figure 22] It is a flowchart of the process performed by the developing device. [Figure 23] It is a flowchart of the process performed by the developing device.

Mode for Carrying Out the Invention

[0008] 〔First Embodiment〕 Hereinafter, a wafer processing system as a substrate processing device according to the present embodiment will be described with reference to the drawings. In this specification, elements having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

[0009] 〔Wafer Processing System〕 First, the configuration of the wafer processing system according to the present embodiment will be described. FIGS. 1 and 2 are a plan view and a front view schematically showing the outline of the configuration of the wafer processing system 1, respectively. In the present embodiment, a case where the wafer processing system 1 is a photolithography processing system that performs a resist film formation process and a development process on the wafer W will be described as an example.

[0010] As shown in Figure 1, the wafer processing system 1 includes a cassette station 2 for loading and unloading cassettes C containing multiple wafers W, and a processing station 3 equipped with multiple processing devices for performing predetermined processing on the wafers W. The wafer processing system 1 has a configuration in which the cassette station 2, the processing station 3, and an interface station 4 for transferring wafers W between the processing station 3 and an adjacent exposure apparatus (not shown) on the opposite side of the processing station 3 are integrally connected. Although two processing stations 3 are installed between the cassette station 2 and the interface station 4 as shown in Figure 1, there may be one or three or more processing stations.

[0011] The cassette station 2 is equipped with multiple cassette mounting tables 21 and wafer transport devices 22 and 23. The cassette station 2 transports wafers between the cassette C placed on the cassette mounting tables 21 and the processing station 3 using the wafer transport device 22 or 23. For this purpose, the wafer transport devices 22 and 23 are each equipped with a drive mechanism having movement paths in each direction, such as the horizontal direction (X direction and Y direction), the vertical direction (Z direction), and around the vertical axis (θ direction), as needed, and may also be equipped with a drive mechanism having movement paths in all directions. At least one of the wafer transfer devices 22 and 23 is capable of transferring a wafer to and from cassette C, and is also capable of transferring a wafer to and from processing station 3. The wafer transfer operation to and from processing station 3 refers, for example, to transferring a wafer to and from a third block G3 that is accessible to the wafer transfer device 33 within processing station 3 (described later). The third block G3 may be equipped with a plurality of transfer devices (not shown) arranged in the vertical direction.

[0012] Furthermore, an inspection device (not shown) for inspecting the wafer W may be provided at a location accessible by either the wafer transport device 22 or 23.

[0013] Processing station 3 is provided with multiple blocks, for example, three blocks G1, G2, and G4, which are the first, second, and fourth blocks. In addition, as shown in Figure 2, multiple layers 31, each containing the first and second blocks G1 and G2, are stacked vertically. For example, the first block G1 is provided on the front side of processing station 3 (the negative X direction side in Figure 1), and the second block G2 is provided on the rear side of processing station 3 (the positive X direction side in Figure 1). A fourth block G4 is provided on the interface station 4 side of processing station 3 (the positive Y direction side in Figure 1) or at the connection point with another adjacent processing station 3. The fourth block G4 may be provided with multiple transfer devices arranged vertically. In addition, the aforementioned third block G3 may be provided inside processing station 3.

[0014] The first block G1 contains multiple processing devices, such as patterning film forming devices and developing devices, which are not shown in the diagram. The patterning film forming devices may include, for example, a resist film forming device as well as an anti-reflective film forming device. For example, multiple processing devices are arranged horizontally. The number, arrangement, and types of these processing devices can be arbitrarily selected.

[0015] These patterning film forming apparatuses and developing apparatuses perform operations such as supplying a predetermined processing solution or a predetermined gas onto a wafer W. In this way, the patterning film forming apparatuses create resist films that are used as masks when forming patterns on the lower layer films, or anti-reflective films that enable efficient light irradiation processes, such as exposure processing. Meanwhile, the developing apparatuses remove a portion of the exposed resist film to form the uneven shape that serves as the mask.

[0016] For example, in the second block G2, heat treatment equipment (not shown) for performing heat treatment such as heating and cooling of the wafer W is arranged in the vertical and horizontal directions. Also in the second block G2, although not shown, a hydrophobic treatment equipment for performing hydrophobic treatment to improve the adhesion between the resist solution and the wafer W, and a peripheral exposure equipment for exposing the outer edge of the wafer W are arranged in the vertical (Z direction in Figure 2) and horizontal directions. The number and arrangement of these heat treatment equipment, hydrophobic treatment equipment, and peripheral exposure equipment can also be arbitrarily selected.

[0017] As shown in Figure 1, a wafer transport region 32 is formed in the area sandwiched between the first block G1 and the second block G2 in a plan view. A wafer transport device 33, for example, is arranged in the wafer transport region 32.

[0018] The wafer transport device 33 has a transport arm 33a that can move, for example, in the Y direction, front-back direction, θ direction, and up-down direction. The wafer transport device 33 moves within the wafer transport area 32 and can transport wafers W to predetermined devices in the surrounding first block G1, second block G2, third block G3, and fourth block G4. If there are multiple processing stations 3 as shown in Figure 1, the wafer transport device 33 provided at the processing station 3 located on the interface station 4 side can transport wafers W to predetermined devices in the fifth block G5, which will be described later, in addition to the first, second, and fourth blocks G1, G2, and G3.

[0019] Multiple wafer transfer devices 33 are arranged vertically, for example, as shown in Figure 2. One wafer transfer device 33 can transfer a wafer W to a predetermined device located at the height of multiple upper layers 31 of the stacked layers 31. Another wafer transfer device 33 can transfer the wafer W to a predetermined device located at the height of multiple layers 31 below those layers 31. Multiple wafer transfer areas 32 are provided to enable this type of wafer transfer W. The number of wafer transfer devices 33 and the number of layers 31 corresponding to one wafer transfer device 33 can be arbitrarily selected, such as providing one wafer transfer device 33 for each layer 31.

[0020] Furthermore, a shuttle transport device (not shown) may be provided in the wafer transport area 32 or in the first block G1 or the second block G2. The shuttle transport device transports the wafer W linearly between a space adjacent to one side of the processing station 3 and another space adjacent to the opposite side.

[0021] Interface station 4 includes a fifth block G5 equipped with multiple transfer devices, and wafer transport devices 41 and 42. Interface station 4 transports wafers W between the fifth block G5, where wafers W are transferred by wafer transport device 33, and the exposure apparatus using wafer transport devices 41 or 42. For this purpose, wafer transport devices 41 and 42 are each equipped with a drive mechanism having movement paths in various directions such as horizontal (X direction, Y direction), vertical (Z direction), and around the vertical axis (θ direction), as needed, and may also be equipped with a drive mechanism having movement paths in all directions. At least one of wafer transport devices 41 and 42 can support the wafer W and transport the wafer W between the transfer devices and the exposure apparatus in the fifth block G5.

[0022] A cleaning device for cleaning the surface of the wafer W, and the aforementioned peripheral exposure device, may be provided within the interface station 4 in a location accessible by either the wafer transport device 41 or 42.

[0023] The inspection device may be provided in the cassette station 2 as described above, but it may also be provided in the processing station 3 and the interface station 4 in a position accessible by any of the transport arms (33, 41, 42 in Figure 1 or Figure 2) located inside each of them.

[0024] The wafer processing system 1 described above is equipped with a control device 100, which is a control unit. The control device 100 is, for example, a computer and has a program storage unit (not shown). The program storage unit stores a program that controls the processing of wafers W in the wafer processing system 1. The program storage unit also stores a program that controls the operation of the drive systems, such as the various processing devices and transport devices, to realize wafer processing in the wafer processing system 1. The program consists of a set of steps necessary to transport and process wafers W in the wafer processing system 1, and the control device 100 outputs control signals to each part of the wafer processing system 1 according to the program, thereby controlling each part as described above to perform the transport and processing. The program may have been recorded on a computer-readable storage medium H and installed from the storage medium H to the control device 100. The storage medium H may include ROM, RAM, or a hard disk, but its structure and type are not limited, and it may be temporary or non-temporary. The control device 100 may include parts for storing, reading, and executing programs for wafer processing, as well as related communications. Furthermore, these parts may be located either inside or outside the wafer processing system 1. The control device 100 may consist of one or more circuits, and may be provided as a single integrated unit or in separate parts.

[0025] [Operation of the wafer processing system] The wafer processing system 1 is configured as described above. Next, an example of wafer processing performed using the wafer processing system 1 configured as described above will be explained.

[0026] First, a cassette C containing multiple wafers W is brought into the cassette station 2 of the wafer processing system 1 and placed on the cassette tray 21. Next, each wafer W in the cassette C is sequentially removed by the wafer transport device 22 or 23 and transported to the transfer device of the third block G3.

[0027] The wafer W, transported to the transfer device in the third block G3, is supported by the wafer transfer device 33 and transported to a hydrophobic treatment device located in the second block G2, where a hydrophobic treatment is performed. Next, the wafer transfer device 33 transports it to a resist film forming device where a resist film is formed on the wafer W. After that, it is transported to a heat treatment device for pre-baking, and then transported to the transfer device in the fifth block G5. Note that if there are multiple processing stations 3 as shown in Figures 1 and 2, the wafer W is first placed in the transfer device in the fourth block G4 before being transported to the transfer device in the fifth block G5, and then transferred between the multiple wafer transfer devices 33. In addition, if necessary, the wafer W may be transported by the wafer transfer device 33 to a peripheral exposure device where the peripheral edge of the wafer is exposed.

[0028] The wafer W, transported to the transfer device of the fifth block G5, is then transported to the exposure device by wafer transport devices 41 and 42 and exposed in a predetermined pattern. The wafer W may be cleaned in a cleaning device before the exposure process.

[0029] The exposed wafer W is transported by wafer transport devices 41 and 42 to the transfer device for the fifth block G5. It is then transported by wafer transport device 33 to a heat treatment device for post-exposure baking.

[0030] The wafer W, which has been baked after exposure, is transferred to the developing apparatus by the wafer transport device 33. The wafers are transported and developed. After development is complete, the wafers W are transported by the wafer transport device 33 to the heat treatment device 40 for post-bake treatment.

[0031] Subsequently, the wafer W is transported by the wafer transport device 33 to the transfer device of the third block G3, and then transported by the wafer transport device 22 or 23 of the cassette station 2 to cassette C on a predetermined cassette tray 21. In this way, the series of photolithography processes is completed.

[0032] It should be noted that the wafer processing system in this disclosure is not limited to the configuration and operation described above. For example, in the above embodiment, the wafer processing system was directly connected to the exposure apparatus and the wafer W was transferred between the interface station 4 and the exposure apparatus, but the wafer processing system does not have to be directly connected to the exposure apparatus. In that case, for example, the wafer W is transported from the cassette station 2 to the processing station 3, the necessary processing is performed, and then it is transported back to the cassette station 2 for removal outside the system. Also, among the processing devices listed, those that are not necessary may not be provided in the wafer processing system, or processing may not be performed in those devices.

[0033] [Explanation of MOR] The resist film formed on the wafer W, which is the substrate, by the resist film formation apparatus of the wafer processing system 1 described above is a resist film composed of metal oxide resist (MOR). This MOR is a negative-type resist that contains, for example, tin (Sn) as a metal, and a ligand is attached to the metal during film formation. Note that "containing metal" here means that it contains metal as a constituent component, and does not mean that it contains metal as an impurity. The resist film made of MOR is exposed by the exposure apparatus described above along the pattern to be formed on the resist film.

[0034] [Explanation of the process used in the comparative example] To facilitate understanding of the processing in the first embodiment performed by the wafer processing system 1, a comparative example will be explained first using the side view of the wafer W shown in Figure 3. In the explanation, the thickness direction of the wafer W is considered the vertical direction, the side on which the resist film R is formed is considered the upper side, and the side on which the underlying film R4, which is etched using the resist film R as a mask, is formed is considered the lower side. The left side of Figure 3 shows the state of the wafer W after exposure by the exposure apparatus described above and before the heat treatment (PEB: Post Exposure Bake) described as post-exposure baking. For the resist film R, the region that is insoluble in the developing fluid supplied to the wafer W when exposed is shown as the insoluble region R1, and the region that is not exposed and soluble in the developing fluid is shown as the soluble region R2.

[0035] The soluble region R2 contains a starting compound M1 with metal M as its core, and in this starting compound M1, multiple ligands L are bound to metal M, for example. The insolubilized region R1 is formed as a result of the starting compound M1 changing and bonding with each other. Specifically, the insolubilized region R1 contains reaction products M2, which are formed when some of the ligands L are removed from metal M constituting the starting compound M1 by exposure, and hydroxyl groups are attached in their place, followed by dehydration condensation between the hydroxyl groups of each starting compound M1, and the metal Ms are bonded to each other via oxygen. These reaction products M2 give the insolubilized region R1 its insolubility with the developing fluid. An intermediate region R3 is interposed between the insolubilized region R1 and the soluble region R2. In the starting compound M1 contained in this intermediate region R3, metal M is in a state where hydroxyl groups are attached in place of the ligands L being removed by exposure. However, because the amount of exposure energy supplied is insufficient, no reaction product M2 is generated in the intermediate region R3, and therefore this intermediate region R3 is soluble in the developing fluid.

[0036] The energy received by the resist film R during exposure decreases towards the bottom of the resist film R, so the insolubilized region R1 has a shape that narrows towards the bottom. Therefore, when PEB is performed and then developing is carried out by supplying developing fluid, as shown by the arrow in Figure 3, this insolubilized region R1 remains as a convex part that forms the resist pattern, but this convex part has a shape that narrows towards the bottom of the resist film R.

[0037] When transferring the pattern of the resist film R to the underlying film R4 by etching, the width of the recesses formed in the underlying film R4 corresponds to the width of the bottom of the recesses in the resist pattern. Therefore, if the convex portions of the resist pattern are reduced in width as they extend downwards (i.e., the recesses of the resist pattern are widened as they extend downwards), the width of the recesses transferred to the underlying film R4 may become larger than the design value. Also, if the thickness of the underlying film R4 is relatively large, the thickness of the resist film R will also be relatively large in order to prevent the disappearance of the resist film R during etching of the underlying film R4. Therefore, the height of the convex portions (immobilized regions R1) of the resist pattern will be relatively large, but in that case, if the lower side of the immobilized region R1 is reduced in width as described above, there is a concern that it may twist or collapse.

[0038] By setting the PEB temperature relatively high, the dehydration condensation between the hydroxyl groups of the starting compound M1 in the intermediate region R3 and the hydroxyl groups remaining in the reaction product M2 in the insolubilized region R1 is promoted. In other words, as shown on the left and in the center of Figure 4, in the intermediate region R3, a portion of it changes from the insolubilized region R1 side towards the soluble region R2 side to become the insolubilized region R1. That is, compared to the case where the PEB temperature is relatively low, the reactivity of the resist film R2 to the developing fluid is increased, and the insolubilized region R1 is expanded. However, even in this case, as shown on the right side of Figure 4, the convex parts (=insolubilized region R1) of the formed resist pattern become narrower as they are directed downwards, so the above-mentioned problem cannot be fully solved.

[0039] For the reasons described above, it is required that the side walls of the insolubilized region R1 after development be formed to approximate a rectangle in side view by increasing the perpendicularity of the side walls of the insolubilized region R1 with respect to the thickness direction of the wafer W and suppressing the narrowing of the lower side. The wafer processing system 1 is configured to meet this requirement when developing the wafer W using gas as the developing fluid.

[0040] In this first embodiment, the wafer W is processed in the order of PEB, development, PEB, development. In other words, PEB and development are repeated in this order. Because the developing fluid supplied to the wafer W is a gas, it is easier to switch between a state in which the developing-reactive substance remains on the surface of the wafer W and a state in which it is removed from the surface, compared to the case in which a liquid stream of developing solution is supplied to the wafer W as the developing fluid to form a liquid film on the wafer W. Taking advantage of this ease of switching, in the first development, only the surface layer of the resist film R is removed. In other words, only a portion of the soluble region R2 and intermediate region R3 is removed in the depth direction. Then, in the second development, the soluble region R2 and intermediate region R3 are removed further in the depth direction, thereby removing the entirety of the soluble region R2 and intermediate region R3.

[0041] The first development is performed under processing conditions that result in a higher development reactivity towards the resist film R than the second development. Looking at the pattern in the width direction (left-right direction), the higher the development reactivity, the easier it is for the insolubilized region R1 to be developed and dissolved, and the lower the development reactivity, the less likely it is for the intermediate region R3 to be dissolved by development. Therefore, by controlling the development reactivity in each stage in this way, it is possible to suppress the narrowing of the lower side of the convex portion (insolubilized region R1) of the resist pattern remaining after the second development, and to approximate the insolubilized region R1 as a rectangle in side view. Note that when developing the resist film (i.e., removing a part of the film), a developing gas is used instead of a developing solution, but for convenience, this removal by gas may also be described as dissolution.

[0042] Furthermore, the process is carried out so that the temperature of wafer W in the second PEB is higher than the temperature of wafer W in the first PEB. During the execution of the second PEB, the upper side of the intermediate region R3 is removed, so the width of the insolubilized region R1 is prevented from widening on the upper side, while the width of the lower side widens. In this way, the convex parts of the resist pattern can be made to approximate a rectangle in a side view.

[0043] The first development described above corresponds to the first development process, and the second development, which is the final development, corresponds to the second development process. The first and second PEB processes correspond to the first and second heat treatment processes, respectively. In this example, as described above, PEB and development are repeated once (i.e., PEB and development are performed twice each), but as will be shown in other examples later, there are cases where the number of repetitions is two or more (i.e., PEB and development are performed three or more times each). In these repetitions, the last development is sometimes described as the final development. In this example, where development is performed only twice, the second development is the final development.

[0044] [Description of the developing apparatus for carrying out the processing of the first embodiment] Next, referring to the longitudinal cross-sectional side view of Figure 5, a developing apparatus 6 that can be installed as a developing apparatus in the wafer processing system 1 described above and that can repeatedly perform PEB and developing as described above will be explained. This developing apparatus 6 is equipped with a processing container 61. The developing apparatus 6 supplies developing gas to the wafer W located in the processing space 60 formed inside the processing container 61 when the processing container 61 is closed, and performs developing. PEB is also performed inside the processing container 61. For example, the processing space 60 is maintained at atmospheric pressure (standard pressure) or near atmospheric pressure, more specifically in the range of atmospheric pressure -10kPa to atmospheric pressure +10kPa, and processing is performed on the wafer W.

[0045] The processing container 61 is composed of a lower member 62 that forms the bottom wall and the lower side wall, and an upper member 63 that forms the top wall and the upper side wall. The processing container 61 is opened and closed by the raising and lowering of the upper member 63 by the lifting mechanism 79. First, the lower member 62 will be described. The lower member 62 is provided with a heat plate 64 that is positioned above the bottom wall of the processing container 61. A heater 65 is embedded inside the heat plate 64, which is both the wafer W mounting area and the heat treatment area for heat treating the wafer W.

[0046] Multiple support pins 66 are provided on the upper surface of the heating plate 64, distributed to support the wafer W on the heating plate 64. The wafer W placed on the heating plate 64 via these support pins 66 is heated to a desired temperature by controlling the output of the heater 65. In the figure, 67 is an insulating member provided around the side of the heating plate 64. A lifting mechanism 68 is provided on the bottom wall of the processing container 61. The lifting operation of the lifting mechanism 68 causes the upper ends of multiple pins 69 to protrude and retract on the upper surface of the heating plate 64, allowing the wafer W to be transferred between the heating plate 64 and the wafer transfer mechanism.

[0047] A gas outlet 71 is open on the upper surface of the heating plate 64, allowing gas to be supplied to the back side (bottom side) of the wafer W supported on the heating plate 64. The gas discharged from the outlet 71 is a purge gas that suppresses the development gas, which has reacted with the resist film R on the upper surface of the wafer W and contains dissolved material of the resist film R, from flowing to the bottom side of the wafer W. It purges the back side of the wafer W to suppress the adhesion of the dissolved material to the bottom surface of the wafer W. Hereafter, the gas discharged from the outlet 71 may be referred to as the back side purge gas.

[0048] The upstream side of the gas supply passage 72, which is connected downstream to the discharge port 71, is connected to a gas supply mechanism 73 that supplies an inert gas, specifically, N2 (nitrogen) gas, as a back-side purge gas to the gas supply passage 72 via a valve V1 and a flow rate adjustment unit 80 in sequence. By opening and closing the valve V1, the supply of back-side purge gas from the discharge port 71 and the supply stoppage are switched. The flow rate adjustment unit 80 is composed of, for example, a mass flow controller and adjusts the flow rate of the gas supplied to the downstream side of the gas supply passage to a desired flow rate. In addition, a back-side supply passage heater 74 is provided around the gas supply passage 72, making it possible to heat the back-side purge gas flowing through the gas supply passage 72 and adjust the temperature of the back-side purge gas. The purpose of enabling this temperature adjustment of the back-side purge gas will be described later.

[0049] Next, the upper member 63 will be described. The upper member 63 is provided with a shower head 75 equipped with numerous discharge ports 76, from which gas is supplied to the wafer W on the hot plate 64. The gap between the side wall of the processing container 61 and the side wall of the shower head 75 is configured as an exhaust port 77. An exhaust passage 78 is connected to the upper wall of the processing container 61, and the downstream side of the exhaust passage 78 is connected to the exhaust mechanism 70 via a valve V3. By opening and closing the valve V3, exhaust from the exhaust port 77 and the cessation of said exhaust can be switched.

[0050] The showerhead 75 is connected to gas supply passages 81, 82, 83, and 84, and each of the gas supply passages 81 to 84 is sequentially fitted with a valve V3 and a flow rate adjustment unit 80 facing upstream. By opening and closing each valve V3, the supply of gas from the gas supply mechanism connected to the upstream side of the gas supply passages 81 to 84 to the showerhead 75 is switched, and the gas supply is stopped. The gas supply mechanism connected to gas supply passage 81 is a developing gas supply mechanism 81A. The developing gas supply mechanism 81A comprises a tank 85 in which developing solution is stored, a gas supply passage 86 opening into the liquid layer of the developing solution in the tank 85, a valve V4 and a flow rate adjustment unit 80 sequentially fitted into the gas supply passage 86 facing upstream, and a gas supply mechanism 87 to which the upstream end of the gas supply passage 86 is connected. The gas supply passage 81 opens into the gas phase of the tank 85. Tank 85 is equipped with a tank heater 88, which heats the developing solution stored in tank 85.

[0051] By opening and closing valve V4, the supply of inert gas from the gas supply mechanism 87 to the tank 85 is switched on and off. This inert gas is, for example, N2 gas, and the supply of N2 gas from the gas supply mechanism 87 causes the developer solution in tank 85 to vaporize by bubbling, becoming developer gas. When valve V6 is opened, this developer gas, along with the carrier gas (N2 gas) supplied from the gas supply mechanism 87, is discharged from the outlet 76 of the shower head 75 into the processing space 60. A heater for the developer supply path is provided to heat the gas flowing through the gas supply path 83, and the mixed gas consisting of developer gas and carrier gas (N2 gas) heading towards the shower head 75 can be heated. The developer solution stored in tank 85 is, for example, acetic acid.

[0052] A developing gas supply mechanism 82A is connected to the gas supply passage 82 as a gas supply mechanism. This developing gas supply mechanism 81B is configured similarly to the developing gas supply mechanism 81A. However, the tank heater 88 of the developing gas supply mechanism 82A is set to a higher temperature than the tank heater 88 of the developing gas supply mechanism 81A, and the developing gas supply mechanism 82A has a higher vaporization efficiency of the developing solution than the developing gas supply mechanism 81A. Therefore, the concentration of developing gas in the mixed gas (developing gas + carrier gas) supplied to the shower head 75 is higher when gas is supplied from the gas supply passage 81 than when gas is supplied from the gas supply passage 82. The developing gas supply mechanisms 81A and 82A, the gas passages 81 and 82, and the flow rate adjustment section 80 and valve V3 interposed in the gas passages 81 and 82, respectively, constitute the developing fluid supply section.

[0053] An N2 gas supply mechanism 83A is connected to the gas supply passage 83 to supply N2 gas as an inert gas. A water vapor supply mechanism 84A is connected to the gas supply passage 84. When the humidity of the processing space 60 is high during PEB execution, it is thought that a dehydration condensation reaction occurs between the hydroxyl groups of the raw material compound M1 in the intermediate region R3 (explained in Figure 3) and the hydroxyl groups remaining in the reaction product M2 in the insolubilization region R1, mediated by the moisture in the processing space 60, thereby widening the insolubilization region R1. On the other hand, if the humidity of the processing space 60 is low, such widening does not occur. Due to these properties of the resist film R, which is MOR, the above-mentioned N2 gas supply mechanism 83A and water vapor supply mechanism 84A are provided to control the width of the insolubilization region R1 by increasing the humidity of the processing space 60 by supplying water vapor and decreasing the humidity of the processing space 60 by supplying an inert gas. In this specification, humidity means relative humidity unless otherwise specified.

[0054] As previously described, in the developing apparatus 6, PEB and developing are performed in the same processing container 61. The wafer W is continuously heated while stored in the processing container 61, but heating during the period when developing fluid is not supplied until the final development is completed is considered PEB, and heating during the period when developing fluid is supplied is considered developing. Thus, PEB and developing are distinguished from each other. Furthermore, in the following explanation, the intermediate region R3 may be shown as part of the soluble region R2, and the intermediate region R3 and the soluble region R2 may not be distinguished.

[0055] The following describes an example of wafer W processing with reference to Figures 6 to 9, which show the correspondence between the changes in the resist film R and the operation of the developing apparatus 6. In these explanatory diagrams, the dashed arrows on wafer W indicate the longitudinal cross-sectional side of the resist film R. Note that some of the components described in Figure 5 are not used in this processing example. In explaining the processing example, the time chart in Figure 10 will also be referred to as appropriate. This time chart shows the change in the development reactivity of the atmosphere in the processing space 60 towards the resist film R, depending on the settings of various processing conditions.

[0056] First, valve V3 of the gas supply passage 83 is opened, and N2 gas is supplied into the processing container 61 from the N2 gas supply mechanism 83A at a predetermined flow rate of A1 sccm, discharged from the shower head 75, and exhausted from the exhaust port 77. Then, with the heating plate 64 heated to a predetermined temperature B1°C by the heater 65, the wafer W is transported into the processing container 61, and the processing container 61 is closed to form the processing space 60. The processing space 60 is made into an N2 gas atmosphere by the supply and exhaust of N2 gas. As the pins 69 (not shown in Figures 6 to 9) supporting the wafer W descend, the wafer W is placed on the heating plate 64 (time t1) and heated to the same B1°C as the heating plate 64. That is, the first PEB is started as shown in Figure 6. Due to this PEB, a predetermined chemical reaction proceeds in the resist film R. However, because the processing space 60 is an N2 gas atmosphere and has relatively low humidity, the reaction that widens the insolubilization region R1 as explained in Figure 4 is suppressed.

[0057] Subsequently, the temperature of the hot plate 64 is set to a predetermined temperature of B2°C, and the valve V3 of the gas supply passage 82 is opened (time t2). The mixed gas (developer gas and carrier gas) supplied from the developing gas supply mechanism 82A is then supplied into the processing container 61 at a predetermined flow rate of A2scccm and discharged from the shower head 75. That is, the first development process begins as shown in Figure 7. Also at this time t2, the valve V3 of the gas supply passage 83 is closed, stopping the supply of N2 gas from the N2 gas supply mechanism 83A to the processing space 60, while the valve V1 is opened, starting the discharge of the back-side purge gas from the discharge port 71 of the hot plate 64.

[0058] The developing gas removes the surface layer of the soluble region R2 of the wafer W, which is heated at B2°C. Furthermore, as described above, the developing gas supply mechanism 82A has a relatively high vaporization efficiency of the developing solution, resulting in a relatively high concentration of developing gas in the mixed gas. Therefore, an atmosphere with relatively high developing reactivity is formed in the processing space 60. Consequently, the upper side of the insolubilized region R1, which is exposed by the removal of the soluble region R2, is also slightly abraded by reaction with the developing gas.

[0059] When the soluble region R2 is removed to a predetermined depth, valve V3 of gas supply passage 82 is closed and valve V3 of gas supply passage 83 is opened, and N2 gas from the N2 gas supply mechanism 83A is again supplied to the processing space 60 at a predetermined flow rate of A1 sccm instead of the mixed gas containing the developing gas. Along with the switching of each valve V3, the temperature of the heating plate 64 is changed to B3°C, which is higher than B1°C during the first PEB (time t3), and the wafer W is heated at B3°C. That is, as the first development is completed, the second PEB is started (Figure 8), the developing gas in the processing space 60 is purged and removed, and the wafer W is heated in an N2 gas atmosphere. Also, at time t3, valve V1 is closed, and the discharge of the back-side purge gas from the discharge port 71 is stopped.

[0060] Thus, in the second PEB, the wafer W is heated to a higher temperature than in the first PEB. As a result, the hydroxyl groups of the reaction product M2 contained in the lower part of the insolubilized region R1 that is in contact with the soluble region R2 undergo dehydration condensation with the hydroxyl groups of the starting compound M1 contained in the soluble region R2 (more specifically, the intermediate region R3). Consequently, the area containing the reaction product M2 expands, and the lower part of the insolubilized region R1 widens.

[0061] Subsequently, the temperature of the hot plate 64 is set to a predetermined temperature B2°C, and the valve V3 of the gas supply passage 81 is opened (time t4). A mixed gas of developing gas and carrier gas supplied from the developing gas supply mechanism 81A is supplied into the processing container 61 at a predetermined flow rate of A2scccm and discharged from the shower head 75. That is, the second development is started as shown in Figure 9. The output of the heater 89 for the developing supply passage is controlled so that the temperature of the mixed gas supplied to the processing space 60 during this second development is the same as the temperature of the mixed gas supplied to the processing space 60 during the first development. The above-mentioned temperature of the hot plate B2°C is set to a temperature of, for example, 120°C or higher to prevent liquefaction of the acetic acid, which is the developing gas, but it is lower than the temperatures B1°C and B3°C used during each PEB (Photobleached Embolization) cycle. At the above time t4, valve V3 of the gas supply passage 83 is closed, stopping the supply of N2 gas from the N2 gas supply mechanism 83A to the processing space 60, and valve V1 is opened, initiating the discharge of purge gas from the back side of the hot plate 64 through the discharge port 71.

[0062] The developing gas removes the soluble region R2 remaining on the wafer W, which is heated at B2°C, downwards. Furthermore, as mentioned above, the vaporization efficiency of the developing solution in the developing gas supply mechanism 81A is lower than that of the developing gas supply mechanism 82A, so the concentration of the developing gas in the mixed gas is relatively high. Therefore, in the processing space 60, an atmosphere with lower developing reactivity is formed than during the first development. As a result, the removal of the soluble region R2 proceeds while suppressing the abrasion of the sides of the insolubilized region R1 at each height that is exposed by the removal of the soluble region R2.

[0063] For example, once the lower layer R4 is completely removed so that it is exposed, valve V3 of gas supply passage 81 is closed and valve V3 of gas supply passage 83 is opened. Then, N2 gas from the N2 gas supply mechanism 83A is supplied again to the processing space 60 instead of the mixed gas containing the developing gas, and the developing gas in the processing space 60 is purged and removed. Valve V1 is closed, and the discharge of the back-side purging gas stops. After that, the processing container 61 is opened and the wafer W is unloaded.

[0064] As described above, in the first embodiment, when developing in stages, processing conditions with high development reactivity are set for the first development to promote the dissolution of the upper side of the exposed insolubilized region R1 from the side. Then, in the second development, when the upper and lower sides of the insolubilized region R1 are exposed, processing conditions with lower development reactivity than the first development are set to suppress the dissolution from the sides of the upper and lower sides, respectively. Furthermore, the processing conditions are set such that the reaction of expanding the insolubilized region R1 is suppressed in the first PEB, and the reaction of expanding the insolubilized region R1 is promoted more in the second PEB than in the first PEB. By setting the processing conditions in this way and performing the processing, the convex portion (insolubilized region R1) of the pattern of the resist film R formed after development can be made to have a shape that approximates a rectangle in side view, by suppressing the lower side from becoming narrower than the upper side.

[0065] [Variations in adjusting development reactivity] In the examples shown in Figures 6 to 9, the parameter of the processing conditions that changes the development reactivity of the processing space 60 between the second development and the first development is the concentration of the developing gas contained in the mixed gas supplied to the processing space 60. That is, the processing conditions are set such that the concentration of the developing fluid in the gas supplied to the processing container 61 where the wafer W is stored is higher during the first development (first development step) than during the second development (second development step). The parameter of the processing conditions to be changed is not limited to the concentration of the developing gas. For example, the processing conditions can be set so that the temperature of the wafer W heated during the first development is higher than the temperature of the wafer W heated during the second development. This allows more thermal energy to be supplied to the developing gas and the resist film R during the first development, making the development reactivity during the first development higher than that during the second development. In order to make the temperature of the wafer W different in each development, the temperature of the heating plate 64 may also be used as the parameter mentioned above.

[0066] A specific example of a process in which the temperature of the hot plate 64 is used to differentiate the development reactivity is shown. In the process shown in Figures 6 to 9, the first and second developments are performed by supplying gas from the development gas supply mechanism 81A, and the temperature of the hot plate 64 during the second development (times t4 to t5) is set to a lower temperature B4°C than the temperature of the hot plate 64 during the first development (times t2 to t3) (B2°C). Except for this difference, the process is carried out in the same manner as the examples shown in Figures 6 to 9. Due to the above-described temperature setting of the hot plate 64, the temperature of the wafer W during the first development is higher than the temperature of the wafer W during the second development, so the development reactivity during the first development can be made higher than the development reactivity during the second development.

[0067] Furthermore, the temperature of the wafer W is not limited to the temperature setting of the heating plate 64 when differentiating the temperature of the wafer W between the first and second development processes. Instead of setting the temperature of the heating plate 64 the same for both processes, the output of the heater 74 for the back-side supply path may be controlled so that the temperature of the back-side purge gas is higher during the first development process than during the second development process.

[0068] Furthermore, the temperature of the developing gas supplied to the processing space 60 may also be used as a parameter to differentiate the development reactivity. An example of a process that changes the temperature of the developing gas in this way is to modify the process shown in Figures 6 to 9 by changing the first and second development processes from using the mixed gas from the developing gas supply mechanisms 81A and 82A to using only the mixed gas from the developing gas supply mechanism 81A. The output of the heater 89 for the developing supply path is controlled so that the temperature of the mixed gas from the developing gas supply mechanism 81A is higher during the first development process than during the second development process, thereby differentiating the temperature of the developing gas in the mixed gas between the first and second development processes.

[0069] Other parameters that can differentiate the development reactivity include the flow rate of the developing gas supplied to the processing space 60, and the flow rate should be set to be greater during the first development than during the second development. An example of processing that differentiates the flow rate of the developing gas in this way is shown in Figures 6 to 9, where the first and second developments are performed using a mixed gas from developing gas supply mechanisms 81A and 82A, but instead, the mixed gas from developing gas supply mechanism 81A is used alone. The operation of the flow rate adjustment unit 80 in the gas supply path 81 should be controlled so that the mixed gas is supplied at a flow rate of A2 sccm during the first development, and at a flow rate lower than A2 sccm, A3 sccm, during the second development. Because the flow rate of the mixed gas supplied to the processing space 60 is greater during the first development than during the second development, the flow rate of the developing gas contained in the mixed gas will also be greater during the first development than during the second development.

[0070] By the way, when processing the wafer W, if the amount of mixed gas containing the developing gas supplied from the developing gas supply mechanism 81A is to be less during the second developing process (next developing process) than during the first developing process (previous developing process), it is preferable to supply inert gas, N2 gas, from the N2 gas supply mechanism 83A to the processing space 60 to compensate for this reduction. In other words, the flow rate of the developing gas supplied to the processing space 60 will be less during the next developing process than during the previous developing process, but the flow rate of the inert gas supplied to the processing space 60 will be greater during the next developing process than during the previous developing process. Note that this inert gas flow rate is the sum of the flow rate of the carrier gas (N2 gas) in the mixed gas supplied from the developing gas supply mechanism 82A and the flow rate of the N2 gas supplied from the N2 gas supply mechanism 83A.

[0071] By setting the flow rate relationship of each gas between the previous development and the next development in this way, the concentration of developing gas in the gas supplied to the processing space 60 becomes lower during the next development than during the previous development. Therefore, after the next development is performed, the purging of the developing gas remaining in the processing space 60 can be completed quickly, and subsequent processing can be carried out. That is, processing can be performed on the wafer W that is next transported to the processing space 60.

[0072] While the preceding and following development processes have been described as the first and second development processes, as will be explained later, there are cases where each process is repeated three or more times by repeating the PEB and development. In such cases, the subsequent processing described above may be the processing of the wafer W that is next transported to the processing space 60, or it may be the processing of the same wafer W that has already undergone PEB and development. In other words, it may be the (n+1)th PEB and development on the wafer W after the nth (n is a positive integer)th PEB and development. In such cases where the subsequent processing is the (n+1)th PEB and development, the low concentration of the developing gas during the nth development allows the developing gas that has entered the fine recesses of the resist pattern to be quickly and reliably removed by purging with N2 gas supplied to the processing space 60 during this (n+1)th PEB. Therefore, the (n+1)th development is performed without being affected by residual developing gas. This is preferable because it allows the shape of the resist pattern to be made closer to the desired shape.

[0073] [Combination of multiple development parameters] As described above, there are multiple parameters related to the processing conditions that affect development reactivity. In each of the processing examples above, only one of these parameters was set to a different value between the first and second development processes. However, by setting multiple parameters to different values ​​between the first and second development processes, it is also possible to make the development reactivity during the first development process higher than that during the second development process.

[0074] When setting different values ​​for multiple parameters in this way, it is not limited to setting all of these parameters so that the development reactivity during the first development is lower than that during the second development. For any one of the parameters, the development reactivity during the second development may be set to be higher than that during the first development. In other words, the effect of increasing the development reactivity during the second development due to a change in one parameter in each development may be canceled out by the effect of decreasing the development reactivity during the second development due to a change in another parameter in each development, resulting in the development reactivity during the first development being lower than that during the second development.

[0075] Specifically, the temperature of the wafer W is set higher during the second development than during the first development, and the concentration of the developing gas in the mixed gas supplied to the processing space 60 is set higher during the first development than during the second development. In other words, the temperature of the wafer W is set to be higher during the second development for better development reactivity. However, the effect of this wafer W temperature is offset by the effect of the developing gas concentration, and the wafer W should be processed in such a way that the development reactivity during the first development is higher than that during the second development.

[0076] Furthermore, it can be experimentally determined that the development reactivity during the first development is higher than that during the second development. In this experiment, multiple wafers W are prepared, in which resist film formation, exposure, and PEB are performed sequentially under the same processing conditions. One wafer W is developed under the processing conditions of the first development, and another wafer W is developed under the processing conditions of the second development. If the time taken for the first and second development differs, the development time of wafer W and the development time of wafer W are made to differ by the amount corresponding to that time difference. Then, the development rate per unit time (etching rate in the depth direction of the soluble region R2 of the resist film R) is calculated for each of these wafers W. If the development rate of wafer W is greater than that of wafer W, then the processing conditions for the first development are more development-responsive than those for the second development. Development may be performed three or more times, and the relationship of the development reactivity in each development in such cases can also be determined by similar experiments.

[0077] [Variations in PEB adjustment] In the processing examples shown in Figures 6 to 9, the reaction that expands the insolubilized region R1 progresses more in the second PEB than in the first PEB. Therefore, the temperature of the heating plate 64 during the second PEB is set to be higher than that during the first PEB, and the temperature of the wafer W is set to be higher during the second PEB than during the first PEB. However, it is not limited to making the temperature of the wafer W different in each PEB in order for the reaction that expands the insolubilized region R1 to progress more in the second PEB than in the first PEB.

[0078] To give a specific example, in the processing examples shown in Figures 6 to 9, the temperature of the hot plate 64 during each PEB is set to the same B1°C. Instead of keeping the temperature of the hot plate 64 constant during each PEB, the flow rate of N2 gas supplied to the processing space 60 is made different for each PEB. For example, during the first PEB, it is set to A1 sccm as described in Figure 6, and during the second PEB, it is set to A3 sccm, which is smaller than A1 sccm. By controlling the flow rate in this way, the concentration of N2 gas in the processing space 60 during the first PEB is made higher than the concentration of the inert gas in the processing space 60 during the second PEB. By adjusting the concentration of the inert gas, N2 gas, in this way, assuming that a small amount of air enters the processing space 60 from outside the processing container 61, the humidity in the processing space 60 will be higher during the second PEB than during the first PEB, and the reaction that expands the insolubilization region R1 will proceed more during the second PEB than during the first PEB.

[0079] Furthermore, when varying the flow rate of N2 gas supplied to the processing space 60 in each PEB as described above, the flow rate of N2 gas A1 sccm in the first PEB may be 0 sccm. In other words, PEB is not limited to being performed with gas supplied to the processing space 60. Hereafter, reactions that widen the insolubilization region R1 may be simply described as widening reactions.

[0080] To ensure that the humidity in the processing space 60 during the second PEB is higher than the humidity during the first PEB, instead of adjusting the flow rate of N2 gas supplied to the processing space 60 as described above, the flow rate of water vapor supplied to the processing space 60 from the water vapor supply mechanism 84A may be adjusted. Specifically, during the first PEB, water vapor is supplied to the processing space 60 at a flow rate of A4 sccm, and during the second PEB, water vapor is supplied to the processing space 60 at a flow rate greater than A4 sccm, namely A5 sccm. Note that the water vapor flow rate A4 sccm during the first PEB may be 0 sccm.

[0081] Furthermore, in the processing examples shown in Figures 6 to 9, the setting is that no purge gas is supplied to the back side during each PEB, but it may also be set to supply it. When purge gas is supplied to the back side during each PEB, the parameters related to the back side purge gas, which is an inert gas and a heating gas, can be set to parameters that make the widening reactivity different. To give a specific example of the processing in that case, in the processing examples shown in Figures 6 to 9, the temperature of the hot plate 64 during each PEB is set to the same B1°C. Instead of keeping the temperature of the hot plate 64 constant during each PEB, the temperature of the back side purge gas is made different for each PEB. Then, by controlling the output of the heater 74, a back side purge gas at F1°C is discharged from the outlet 71 during the first PEB, and a back side purge gas at F2°C, which is higher than F1°C, is discharged from the outlet 71 during the second PEB. The heat from the heating plate 64 and the heat from the purge gas on the back side are added together, so the temperature of the wafer W is higher during the second PEB than during the first PEB. Therefore, the wafer expansion reactivity is higher during the second PEB than during the first PEB.

[0082] Alternatively, instead of changing the temperature of the back-side purge gas in each PEB, the flow rate may be changed. Specifically, by controlling the operation of the flow rate adjustment unit 80 of the gas supply passage 72, the back-side purge gas is supplied to the processing space 60 at F3 sccm during the first PEB, and at F4 sccm, which is greater than F3 sccm, during the second PEB. By changing the flow rate of the back-side purge gas between the first and second PEBs in this way, the concentration of inert gas in the processing space 60 is increased during the second PEB compared to the first PEB, thereby reducing humidity. As a result, the widening reactivity is higher in the second PEB than in the first PEB.

[0083] [Combinations of parameters for multiple PEBs] As described above, there are multiple parameters for the processing conditions related to the expansion reaction of the insolubilization region R1 during PEB. Only one of these parameters may be set to a different value between each PEB, or multiple parameters may be set to different values ​​between each PEB.

[0084] When setting different values ​​for multiple parameters in this way, it is not necessary to set all of these parameters so that the expansion response during the second PEB is higher than the expansion response during the first PEB. For any of the parameters, the expansion response during the first PEB may be set to be higher than the expansion response during the second PEB. In other words, the effect of increasing the expansion response during the first PEB due to each change in a certain parameter may be canceled out by the effect of increasing the expansion response during the second PEB due to each change in another parameter, resulting in the expansion response during the second PEB being higher than the expansion response during the first PEB.

[0085] To give a specific example, the humidity in the processing space 60 is set higher during the first PEB than during the second PEB, and the temperature of the wafer W is set higher during the second PEB than during the first PEB. In other words, the humidity is set to be higher during the first PEB for better expansion reactivity. However, this effect of humidity is offset by the effect of the wafer W temperature, and the wafer W should be processed in such a way that the expansion reactivity during the second PEB is higher than that during the first PEB.

[0086] Furthermore, experiments have confirmed that the widening reactivity during the second PEB is higher than that during the first PEB. In this experiment, multiple wafers W are prepared, each with a resist film produced and exposed under the same processing conditions. One wafer W is subjected to PEB under the processing conditions of the first PEB, and another wafer W is subjected to PEB under the processing conditions of the second PEB. If the time taken for the first and second PEBs differs, the time taken for PEB on wafer W and the time taken for PEB on wafer W are adjusted accordingly in this experiment. Then, these wafers W are developed under the same conditions, and if the width of the insolubilized region R1 is larger on wafer W than on wafer W, then the processing conditions for the second PEB are higher in terms of widening reactivity than those for the first PEB. In some cases, PEB may be performed three or more times, and the relationship of the widening reactivity in each PEB in such cases can also be determined by the above experiment.

[0087] [Regarding the repetition of the process and the development reaction in each step] In the processes shown in Figures 6 to 9, the number of repetitions for PEB and development was set to one (two executions each for PEB and development). However, the number of repetitions may be set to two (three executions each for PEB and development) to gradually etch the soluble region R2 downwards. In other words, an additional development process may be performed between the first development step (initial development) and the second development step (final development). The process may also be performed with more than two repetitions. A higher number of repetitions is preferable because it allows the insoluble region R1 after development to be approximated as a rectangle in a side view. However, from the viewpoint of increasing the throughput of the development apparatus 6, a lower number of repetitions is preferable.

[0088] When setting the number of PEB and development repetitions to two or more times, and performing development three or more times, the processing conditions described above may be set so that the development reactivity differs for each development cycle. For example, if development is performed three times, the processing conditions can be set so that the development reactivity gradually decreases as the cycle progresses, as shown in Figure 11, resulting in different development reactivity for each cycle.

[0089] Figure 11, like Figure 9, is a time chart showing the change in the development reactivity of the atmosphere in the processing space 60 towards the resist film R. In the chart, time t11 to t12 is the period during the first PEB, time t12 to t13 is the period during the first development, time t13 to t14 is the period during the second PEB, time t14 to t15 is the period during the second development, time t15 to t16 is the period during the third PEB, and time t16 to t17 is the period during the third development. Figure 12 is a longitudinal cross-sectional side view of the wafer W showing the change in the resist film R when processing is performed while controlling the development reactivity as shown in Figure 11, and development is indicated as DEV.

[0090] Furthermore, when developing three or more times, the processing conditions may be set so that the development reactivity is the same for multiple consecutive developments. For example, if three developments are performed, the processing conditions may be set so that the development reactivity is the same for the first and second developments, as shown in Figure 13. Alternatively, the processing conditions may be set so that the development reactivity is the same for the second and third developments. However, as shown in Figure 11, it is preferable to gradually decrease the development reactivity as the number of developments progresses, so that the side walls of the insolubilized region R1 dissolve more towards the top, and the insolubilized region R1 after development can be made to more closely resemble a rectangle in a side view.

[0091] In the example shown in Figure 11, the processing conditions are set so that the development reactivity is the same during development in the same cycle. However, the processing conditions may also be set so that the development reactivity changes during development in the same cycle. In other words, the development reactivity may be changed by changing the parameters described above during development. Figures 14 and 15 show specific examples of how to change the development reactivity during development in the same cycle, when PEB and development are performed three times, as in the example in Figure 11.

[0092] The differences between the processing examples in Figures 14 and 15 and the processing example in Figure 11 will be explained. In the example shown in Figure 14, the development reactivity gradually decreases during the first and second development processes. The development reactivity becomes equal at the end of the first development process (time t13) and the start of the second development process (time t14), and then equal at the end of the second development process (time t15) and the start of the third development process (time t16).

[0093] In the example shown in Figure 15, the development reactivity is set to remain at D1 during the first development, but during the second and third developments, the development reactivity repeatedly changes between D1 and D2, which is lower than D1. The duration of the development periods for the first to third developments is the same, and the third development has a longer period of development reactivity at D2 because the development reactivity repeats between D1 and D2 more times than the second development. In the processing examples in Figures 14 and 15, the magnitude of the development reactivity is first development > second development > third development, and therefore, as in the example in Figure 11, the development reactivity gradually decreases as the number of developments progresses. As shown in the examples in Figures 14 and 15, the development reactivity does not have to be set to be constant during the execution of each development.

[0094] [Regarding final development] Figure 16 is a chart showing the progression of development reactivity when the PEB and development process is repeated twice, as explained in Figure 10. Therefore, the final development in the process shown in Figure 16 is the second development. One difference from the process in Figure 10 is that in the process in Figure 16, the processing conditions are changed so that the development reactivity increases at time t4A, which is a predetermined time after the start of the final development at time t4. In other words, at least one parameter involved in the development reactivity described above is changed. After time t4A, the supply of developing gas is stopped at time t5, similar to the process in Figure 10, and the development reactivity becomes 0.

[0095] The reason for increasing the development reactivity during the final development is that if the development reactivity is too low during the final development, as shown on the left and in the center of Figure 17, some of the resist that constituted the soluble region R2 may adhere to the wafer W and remain, becoming foreign matter R5. By increasing the development reactivity during the final development, the foreign matter R5 is dissolved, so that no foreign matter R5 remains on the wafer W at the end of the final development, as shown on the right side of Figure 17.

[0096] In the chart shown in Figure 16, the development reactivity is assumed to be constant from time t4A until time t5, but the development reactivity may be gradually increased from time t4A to time t5. Furthermore, as shown in the chart in Figure 18, gradually increasing the development reactivity from time t4, when the final development begins, until time t5, when the final development stops, also constitutes increasing the development reactivity during the final development process.

[0097] Furthermore, after the final development to remove the foreign matter R5, a process to remove the foreign matter R5 may be performed, such as supplying developer from a nozzle to the wafer W to form a liquid film of the developer on the wafer W, or exposing it to plasma. This process to remove the foreign matter R5 may be performed regardless of whether or not the development transport efficiency is improved during the final development. By performing this process to remove the foreign matter R5, any remaining soluble regions R2 will be removed. Therefore, at the end of the final development, the soluble regions R2 of the resist film R may not be completely removed and may remain on the wafer W as a thin layer. In other words, the final development only needs to etch the soluble regions R2 to the planned depth, and is not limited to being performed in a way that exposes the underlying film R4.

[0098] [Regarding the repetition of the process and the reactivity of PEB in each iteration] This section describes how to perform PEB and development twice, and how to process the material so that there is a difference in the expansion reactivity of the insolubilized region R1 between the first and second PEB processes. As explained in Figures 13 to 15, if PEB and development are performed three or more times, the processing conditions for each PEB process may be set so that the expansion reactivity gradually increases with each subsequent PEB process, thereby making the insolubilized region R1 after development more similar in shape to a rectangle when viewed from the side. As a specific example, the temperature of the hot plate 64 may be increased with each subsequent process to gradually increase the expansion reactivity in this way.

[0099] Furthermore, when performing PEB three or more times, the processing conditions may be set so that the widening reactivity is the same for multiple consecutive times. Specifically, if three PEBs are performed and the widening reactivity is controlled by the temperature of the hot plate 64, the temperature of the hot plate 64 may be set to be the same for the first and second PEBs, or the temperature of the hot plate 64 may be set to be the same for the second and third PEBs.

[0100] [Treatment using mist] The developing fluid supplied to the wafer W is not limited to gas, but may also be a mist. Figure 19 shows a longitudinal cross-sectional side view of a developing apparatus 6A equipped with a nozzle 91 that discharges the mist into the processing space 60. The nozzle 91 is provided on the upper member 63 that constitutes the processing container 61, and the downstream ends of the flow paths 92 and 93 are connected to the nozzle 91. Flow path 92 is connected to a storage section 95 where the developing solution is stored via a pump 94. Flow path 93 is connected to an N2 gas supply mechanism 83A via a valve V5 and a flow rate adjustment section 80 in order toward the upstream side.

[0101] Pump 94 supplies developer from storage unit 95 to nozzle 91. When developer is supplied to nozzle 91, valve V5 is opened and N2 gas supplied from N2 gas supply mechanism 83A is supplied to nozzle 91 at a predetermined flow rate. The developer and N2 gas are mixed in nozzle 91, causing the developer to atomize and be discharged into processing space 60. By using this mist instead of developer gas, the developing apparatus 6B can process the wafer W in the same way as the developing apparatus 6A.

[0102] Incidentally, in this developing apparatus 6A, as described above, the operation of the pump 94 may be controlled to make the developing reactivity different between each developing cycle. When the developing reactivity is increased, the amount of developer supplied to the nozzle 91 by the pump 94 is increased so that a large amount of developer is supplied to the processing space 60 as a mist, and when the developing reactivity is decreased, the amount of developer supplied to the nozzle 91 by the pump 94 is decreased so that a small amount of developer is supplied to the processing space 60 as a mist.

[0103] Figure 20 shows a longitudinal cross-sectional side view of a modified developing apparatus 6B, which is a modified version of developing apparatus 6A. The difference between developing apparatus 6B and developing apparatus 6A is that multiple sets of flow path 92, pump 94, and developing solution storage section 95 are provided, so that developing solution is supplied to the nozzle 91 from any of the storage sections 95 to generate developing mist. The developing solution stored in each storage section 95 consists of a component that causes the developing reaction (developing component) and a solvent, and the concentration of the developing component in the developing solution differs between the storage sections 95. To increase the developing reactivity, the developing solution is supplied to the nozzle 91 from a storage section 95 containing a developing solution with a high concentration of developing component, and to decrease the developing reactivity, the developing solution is supplied to the nozzle 91 from a storage section 95 containing a developing solution with a low concentration of developing component, thereby making the developing reactivity different for each development cycle.

[0104] In the developing apparatus 6 shown in Figure 6, the vaporization efficiencies of the tanks 85 of the developing gas supply mechanisms 81A and 82A are different, so that the concentrations of developing gas in the mixed gas supplied to the processing space 60 from each of the developing gas supply mechanisms 81A and 82A are different. Instead of having different vaporization efficiencies between the developing gas supply mechanisms 81A and 82A, a configuration in which developing solutions with different concentrations of developing components are used may be adopted, as in the example in Figure 20. That is, by making the concentrations of developing components in the developing solutions stored in the tanks 85 of the developing gas supply mechanisms 81A and 82A different, the concentrations of developing gas, i.e., vaporized developing components, in the gas supplied to the processing space 60 from each of the developing gas supply mechanisms 81A and 82A are different, so that the developing reactivity differs each time.

[0105] [Second Embodiment] Figure 21 is a longitudinal cross-sectional side view of the developing apparatus 101 according to the second embodiment. Regarding the developing apparatus 101, the main difference from the developing apparatus 6 is that the processing container 61 is not divided vertically, and a transport port 102 opening in the side wall is opened and closed by a gate valve G, allowing the wafer W to be transported by the wafer transport device 33. In the figure, 103 is a stage that forms a mounting section on which the wafer W is placed, and, similar to the hot plate 64 in the first embodiment, the placed wafer W is heated by an embedded heater 65. The developing apparatus 101 is also provided with a pin 69 that moves up and down by a lifting mechanism 68, similar to the hot plate 64, for the transfer of wafer W between the wafer transport device 33 and the stage 103, but this is not shown in the figure.

[0106] Similar to the first embodiment, the processing container 61 is connected to gas supply passages 82-84, which supply developing gas, N2 gas, and water vapor to the processing space 60, respectively. The processing container 61 is also connected to gas supply passages 97 and 98. Similar to the other gas supply passages 82-84, valves V3 and flow rate adjustment units 80 are sequentially installed in gas supply passages 97 and 98. A developing gas supply mechanism 97A and a dilution gas supply mechanism 98A are connected to the upstream ends of gas supply passages 97 and 98, respectively. HBr gas, a strong acid, is supplied as the developing gas from the developing gas supply mechanism 97A. A heater 104 is provided to heat the developing gas flowing through gas supply passage 97 and adjust its temperature. In this example, each gas is supplied to the processing space 60 without passing through the showerhead 75.

[0107] Dilution gas supply mechanism 98A supplies, for example, BCl3 gas as a dilution gas. When developing gas is supplied from developing gas supply mechanism 97A to the processing space 60, dilution gas is also supplied from dilution gas supply mechanism 98A to the processing space 60. In addition, developing gas supply mechanism 82A supplies acetic acid gas, which is a weak acid, as a developing gas to the processing space 60, similar to the first embodiment. Therefore, developing gas supply mechanisms 97A and 82A supply developing gas containing HBr, the first compound, and developing gas containing acetic acid, the second compound, respectively, and the first compound is more acidic than the second compound. That is, the acid dissociation constant (Ka) of the first compound is larger than that of the second compound.

[0108] [Regarding vacuum processing] In this second embodiment, the exhaust mechanism 70 exhausts the inside of the processing container 61, thereby creating a vacuum atmosphere in the processing space 60 at a preset pressure lower than atmospheric pressure, specifically, for example, 10°C. 3 PEB and development are performed under a pressure of Pa or less. The reason for this vacuum treatment is as follows: Between the formation of the resist film R on the wafer W and before PEB is performed, some of the raw material compound M1 in the soluble region R2 decomposes and settles as an impurity in the lower part of the soluble region R2. It is thought that when the processing space 60 becomes a vacuum atmosphere, this impurity is removed from the insolubilized region R1. In the space formed by the removal of such impurities, some of the raw material compound M1 in the soluble region R2 moves, for example, by its own weight. That is, it is thought that the density of the raw material compound M1 in the lower part of the soluble region R2 increases, while the density of the raw material compound M1 in the upper part of the soluble region R2 decreases.

[0109] As described above, the reaction product M2 in the insolubilized region R1 reacts with the starting compound M1 in the soluble region R2, causing the lower part of the insolubilized region R1 to widen during PEB. Therefore, performing each PEB in a vacuum atmosphere is preferable because it adjusts the distribution of the starting compound M1 in the soluble region R2 and widens the lower part of the insolubilized region R1. In this example, each PEB is performed in a vacuum atmosphere, but this widening can also be achieved by performing only one of the PEBs in a vacuum atmosphere. Furthermore, while it is sufficient to create a vacuum atmosphere during PEB to enhance the widening of the insolubilized region R1, in this example, development is also performed in a vacuum atmosphere to prevent a decrease in throughput.

[0110] The following describes an example of wafer W processing using the developing apparatus 101, focusing on the differences from the processing shown in Figures 6 to 10 using the developing apparatus 6, with the example of performing PEB and developing twice each. In this example, developing gas is supplied only from the developing gas supply mechanism 97A of the developing gas supply mechanisms 82A and 97A. Refer to the flowchart in Figure 22 as appropriate for the explanation.

[0111] First, the processing space 60 is evacuated, and a vacuum atmosphere at a predetermined pressure is created. Then, for example, the wafer W is transported to the processing space 60 by the wafer transport device 33 through a transport area with a vacuum atmosphere outside the processing container 61. The transport opening 102 of the processing container 61 is closed, and N2 gas is supplied to the processing space 60. Then, the wafer W is placed on the stage 103 heated to B1°C, and the first PEB is performed in an N2 gas atmosphere (step S1).

[0112] Next, the supply of N2 gas to the processing space 60 is stopped, and developing gas and diluting gas are supplied to the processing space 60 from the developing gas supply mechanism 97A and the diluting gas supply mechanism 98A, respectively. A mixed gas is then supplied to the processing space 60, and the first development is performed (Step S2). After that, the supply of developing gas and diluting gas to the processing space 60 is stopped, the first development is stopped, and N2 gas is supplied, and the second PEB is started in an N2 gas atmosphere (Step S3).

[0113] Next, the mixed gas is supplied to the processing space 60 again, and the second development is performed (step S4). After that, the supply of developing gas and diluent gas to the processing space 60 is stopped, the first development is stopped, and N2 gas is supplied, purging the mixed gas from the processing space 60, and the wafer W is removed from the processing space 60. From the loading to the unloading of the wafer W, the processing space 60 is maintained at the vacuum pressure described above, so each PEB and each development is performed at that vacuum pressure.

[0114] In the processing of the developing apparatus 101 described above, the processing conditions for the first and second development are set so that the development reactivity is higher in the first development, similar to the first embodiment. That is, one or more of the parameters such as the temperature of the wafer W, the temperature of the developing gas, the flow rate of the developing gas, and the concentration of the developing gas in the mixed gas supplied to the processing space 60 are set to different values ​​in the first and second development, so that the development reactivity is higher in the first development than in the second development. The temperature of the developing gas and the flow rate of the developing gas supplied to the processing space 60 can be changed by changing the output of the heater 104 and changing the operation of the flow rate adjustment unit 80 of the gas supply path 98, respectively. Furthermore, the processing conditions for the first and second PEB can be set so that the widening reactivity is higher in the second PEB, similar to the first embodiment.

[0115] In this example, the HBr used as the developing gas has a relatively high reactivity with the resist film R. To prevent excessive etching of the insolubilized region R1, for example, the temperature of stage 103 during each development is set lower than the temperature of stage 103 during each PEB. The temperature of stage 103 during each development is, for example, room temperature or a temperature near room temperature, such as 10°C to 40°C.

[0116] Incidentally, a discharge port 71 may be provided on the stage 103 so that a back-side purge gas is supplied to the back surface of the wafer W during development, similar to the first embodiment. Although this back-side purge gas has been described as an inert gas, it is not limited to being an inert gas in the first and second embodiments, and for example, a gas containing a developing gas may be used. The developing gas may be any of the developing gases described so far, and the dissolved resist film R attached to the back surface of the wafer W is removed by the developing gas. In some development cycles, including the final development cycle, the developing gas may be supplied as the back-side purge gas, while in other cycles, a gas without a developing gas may be supplied as the back-side purge gas.

[0117] In addition to supplying the purge gas to the back side, the techniques described in the first embodiment can also be applied to the second embodiment. Therefore, in the second embodiment, for example, the number of repetitions of PEB and development is arbitrary, and the relationship between the development reactivity levels of each development cycle, the change in development reactivity during the same development cycle, and the relationship between the widening reactivity levels of each PEB cycle can be controlled in the same way as in the example described in the first embodiment.

[0118] [Other examples of operation of the developing apparatus of the second embodiment] Next, we will explain an example of processing using developing gas supplied from developing gas supply mechanisms 82A and 97A, respectively, with reference to the flowchart in Figure 23, focusing on the differences from the processing example described in Figure 22. First, the wafer W, which has been transported to the processing space 60 under vacuum pressure, is placed on the stage 103 set to B1°C and heated at B1°C to perform the first PEB (Step S11). Then, gases are supplied from the developing gas supply mechanism 97A and the dilution gas supply mechanism 98A, respectively, and a mixed gas of these gases is supplied to the processing space 60 (Step S12). That is, a gas containing HBr, a strong acid, is supplied to the wafer W as the developing gas, and the first development is performed. To prevent excessive reaction by HBr, the temperature of the stage 103 is within the range described above, and is set to B5°C, which is lower than B1°C.

[0119] Subsequently, the supply of the mixed gas to the processing space 60 is stopped, and a second PEB is performed on the wafer W. To increase the widening reactivity, the temperature of the stage 103 is set to B3°C, which is higher than B1°C and B5°C (step S13). Then, the mixed gas is supplied from the developing gas supply mechanism 82A. That is, a gas containing acetic acid, a weak acid, is supplied to the wafer W as the developing gas, and the second development is performed (step S14). To prevent the liquefaction of the acetic acid developing gas, the temperature of the stage 103 in step S14 is set to the temperature at which the developing gas was supplied as described in the first embodiment (B2°C), and this B2°C is higher than the temperature of the stage 103 in step S12, which is B5°C.

[0120] After the second development is complete, the processing space 60 is purged with N2 gas, and the wafer W is removed from the processing space 60. In the above process, as shown in Figure 10, the development reactivity is higher during the first development than during the second development due to the difference in the type of gas used. Note that the processing conditions other than the type of gas used during the first and second development may be the same or different.

[0121] The HBr used as the developing gas during the first development has a relatively small molecular weight and therefore easily penetrates the resist film R. If this HBr is released from the resist film R of the wafer W after it has been removed from the processing container 61, there is a risk that it may corrode the metals that make up the equipment and systems surrounding the wafer W. To prevent this, in steps S11 to S14, acetic acid gas is used as the developing gas for the second development, instead of HBr.

[0122] To explain in detail the reason for changing the type of developing gas in this way, during the second PEB in step S13, the temperature of the hot plate 64 is higher than during the first development in step S12, so the HBr that penetrated the resist film R during the first development volatilizes and is removed. Subsequently, during the second development in step S14, HBr gas is not supplied as the developing gas, so no further penetration of HBr into the resist film R occurs. Furthermore, during this second development, the temperature of the hot plate 64 is higher than the temperature of the hot plate 64 during the first development, so further volatilization of HBr from the resist film R proceeds.

[0123] Therefore, even if the wafer W removed from the developing apparatus 101 is exposed to a temperature environment higher than the temperature during the first development, the amount of HBr released from the resist film R will be zero or negligible. Furthermore, since acetic acid has a relatively large molecular weight, penetration into the resist film R is unlikely. Even if penetration occurs and acetic acid remains in the resist film R while the wafer W is removed from the processing space 60 of the developing apparatus 101, and acetic acid is released from the resist film R after removal, it is a weak acid and therefore has low corrosiveness to metals. In other words, the method of steps S11 to S14 is preferable because it prevents the occurrence of corrosion problems. When repeating PEB and development three or more times, HBr gas may be used for each development from the first to the m (m is an integer) development, and acetic acid gas may be used for each development from the m+1 development to the final development.

[0124] In each embodiment, PEB and development are described as being performed in the same processing container 61, but they may be performed in separate processing containers 61. PEB and development may be performed in different processing containers 61. Also, different PEB cycles may be performed in different processing containers 61, or different development cycles may be performed in different processing containers 61. When processing with the wafer processing system 1 described above, PEB is performed in the heat processing apparatus, development is performed in the development apparatus, and wafers W are transported between the heat processing apparatus and the development apparatus by each wafer transport device 33. Note that the gas used for PEB is a gas with low impact on the surroundings, such as N2 gas. Therefore, a heat processing apparatus that performs only PEB without development may not have a processing container 61. As described above, a substrate processing apparatus that performs PEB and development may be configured to have one processing container, such as the development apparatus 6, and perform each process in that processing container, or it may be configured to have a device with a mounting section for each wafer W and a transport device (transport mechanism) for transporting wafers W between these devices.

[0125] Furthermore, although the second embodiment described each process as being performed under vacuum pressure, it is not limited to being performed under vacuum pressure. Either PEB or development, any of the PEB processes, or any of the development processes may be performed under atmospheric pressure. For example, the first PEB may be performed under atmospheric pressure, and the processes from the first development onward may be performed under vacuum pressure. In the first embodiment as well, any or all of the PEB processes and development processes may be performed under a vacuum atmosphere. Note that PEB is not limited to being performed by placing the wafer on the hot plate 64, but may also be performed by irradiating the wafer W with light from an LED or the like.

[0126] Furthermore, it is not necessary to perform PEB multiple times. After performing PEB in the processing container 61, developing gas may be supplied, and the processing conditions may be changed during the supply of this developing gas to reduce the developing reactivity. The first development is performed before the change in processing conditions, and the second development is performed after the change in processing conditions. In addition, the configuration of the substrate processing apparatus shown as a developing apparatus can be modified as appropriate. The flow path configuration for introducing each gas into the processing space 60, the position of the heater for heating the gas in the flow path, etc. can be changed as appropriate.

[0127] Furthermore, in each embodiment, the substrate to be processed is not limited to a wafer, but may be, for example, a substrate for manufacturing a flat panel display or a mask substrate for manufacturing a mask for exposure. Therefore, a rectangular substrate may also be processed. The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The above embodiments may be omitted, replaced, modified and combined in various ways without departing from the scope and spirit of the appended claims. [Explanation of Symbols]

[0128] M Metal R resist film R1 Insolubilized region R2 Non-exposed area W wafer

Claims

1. In a substrate processing method in which a developing fluid, which is a gas or mist, is supplied to a substrate to develop a resist film containing metal formed on the substrate and to form a pattern, A first heat treatment step involves heat-treating the substrate after the resist film has been exposed along the pattern, A first developing step involves supplying the developing fluid to the substrate that has undergone the first heat treatment step, thereby removing a portion of the resist film in the depth direction, A second developing step involves supplying the developing fluid to the substrate on which the first developing step has been performed to form the pattern, and removing the region from which the resist film was removed by the first developing step in the depth direction up to the development completion position. A substrate processing method comprising the following:

2. The substrate processing method according to claim 1, further comprising a second heat treatment step of heat-treating the substrate after the first development step has been performed and before the second development step has been performed.

3. The substrate processing method according to claim 2, wherein the first developing step is performed under processing conditions that result in a higher development reactivity to the resist film than the second developing step.

4. The substrate processing method according to claim 3, wherein the processing conditions that result in high development reactivity are processing conditions that are achieved by at least one of (1) to (3). (1) The concentration of the developing fluid in the gas supplied to the processing container in which the substrate is stored is higher in the first developing step than in the second developing step. (2) The amount of developing fluid supplied into the processing container is greater in the first developing step than in the second developing step. (3) The first developing step includes a step of heating the substrate while supplying the developing fluid, wherein the temperature of the substrate to which the developing fluid is supplied in the first developing step is higher than the temperature of the substrate to which the developing fluid is supplied in the second developing step.

5. The substrate processing method according to any one of claims 1 to 3, wherein the second heat treatment step is performed under processing conditions that increase the reactivity of the resist film insolubilizing it with the developing fluid compared to the first heat treatment step.

6. The substrate processing method according to claim 5, wherein the processing conditions for increasing the reactivity that causes insolubilization are processing conditions that are performed by at least one of (a) to (d). (a) The first heat treatment step and the second heat treatment step include the step of placing the substrate on the mounting section, The temperature of the aforementioned part in the second heat treatment step is higher than the temperature of the hot plate in the first heat treatment step. (b) The first heat treatment step and the second heat treatment step include a step of supplying a heating gas to the lower surface of the substrate, The temperature of the heating gas in the second heat treatment step is higher than the temperature of the heating gas in the first heat treatment step. (c) The first heat treatment step and the second heat treatment step include a step of supplying an inert gas to the lower surface of the substrate, The flow rate of the inert gas supplied to the substrate in the second heat treatment step is greater than the flow rate of the inert gas supplied to the substrate in the first heat treatment step. (d) The first heat treatment step and the second heat treatment step include the step of placing the substrate on a mounting portion provided in a processing container in which the substrate is stored and heating it, and supplying an inert gas into the processing container, In the first heat treatment step, the concentration of the inert gas in the treatment container is greater than the concentration of the inert gas in the treatment container in the second heat treatment step.

7. A substrate processing method according to any one of claims 1 to 3, further comprising a step of changing the processing conditions during the second development step so as to increase the development reactivity to the resist film.

8. The developing fluid is supplied to the substrate multiple times. A substrate processing method according to any one of claims 1 to 3, wherein the first developing step is a step of supplying the developing fluid for the first time, and the second developing step is a step of supplying the developing fluid for the final time, and further comprising a step of gradually decreasing the developing reactivity of the developing fluid with respect to the resist film as the number of times progresses.

9. The substrate processing method according to claim 2, wherein the first heat treatment step or the second heat treatment step is a step of heat treating the substrate in a processing container in which a vacuum atmosphere is formed.

10. The first developing step includes supplying the developing fluid containing the first compound to the substrate, The second developing step includes supplying the developing fluid containing the second compound to the substrate, The substrate processing method according to any one of claims 1 to 3, wherein the first compound is a compound that is more strongly acidic than the second compound.

11. In a substrate processing apparatus that supplies a developing fluid, which is a gas or mist, to a substrate to develop a resist film containing metal formed on the substrate and to form a pattern, A heat treatment unit for heat-treating the substrate after the resist film has been exposed along the pattern, A developing fluid supply unit that supplies developing fluid to the substrate, A first developing step involves supplying the developing fluid to the substrate that has undergone heat treatment by the heat treatment unit, thereby removing a portion of the resist film in the depth direction. A control unit that outputs a control signal to perform a second development step, which involves supplying the developing fluid to the substrate on which the first development step has been performed to form the pattern, and removing the region from which the resist film was removed by the first development step in the depth direction up to the development completion position. A substrate processing apparatus equipped with the following:

12. A storage medium for storing computer programs used in a circuit board processing device, The computer program is a storage medium having a set of steps configured to execute the substrate processing method described in any one of claims 1 to 3.

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