Liquid treatment apparatus and liquid treatment method

Abstract

To control the temperature distribution within a substrate surface when a paddle is formed on a substrate and the substrate is subjected to liquid processing.SOLUTION: A liquid processing device that performs liquid processing with processing liquid on a substrate includes: a substrate holding portion that holds and rotates the substrate; and a spray nozzle positioned above the substrate held by the substrate holding portion and spraying liquid that does not promote the liquid processing onto an in-plane area of the substrate including the center of the substrate.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a liquid processing apparatus and a liquid processing method.

Background Art

[0002] Patent Document 1 discloses a paddle-type photoresist developing apparatus that supplies a developing solution from a nozzle onto a workpiece held by a chuck device, and rotates a spinner constituting the chuck device after a certain period of time to shake off the developing solution on the workpiece. The apparatus includes a nozzle that mixes the developing solution and air to eject a mist-like developing solution, and at least a part of the developing solution pipe leading to this nozzle is disposed within a circulation path of temperature-controlled water.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The technology according to the present disclosure controls the temperature distribution within the plane of a substrate when forming a paddle of a processing liquid on the substrate and performing liquid processing on the substrate.

Means for Solving the Problems

[0005] One aspect of the present disclosure is a liquid processing apparatus that performs liquid processing on a substrate with a processing liquid, including a substrate holding unit that holds and rotates the substrate, and a spray nozzle that is located above the substrate held by the substrate holding unit and sprays a liquid that does not promote the liquid processing onto a region within the plane of the substrate including the center of the substrate. The liquid treatment is a development treatment, the treatment liquid is a developer, the liquid is water, and the temperature of the substrate or the developer on the substrate is controlled by the heat of vaporization of the water sprayed by the spray nozzle. .

Effects of the Invention

[0006] According to the present disclosure, when forming a paddle of a processing liquid on a substrate and subjecting the substrate to liquid processing, the temperature distribution within the substrate surface can be controlled.

Brief Description of the Drawings

[0007]

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Embodiments for Carrying Out the Invention

[0008] For example, in the manufacturing process of semiconductor devices, a resist film is formed on the surface of a substrate such as a semiconductor wafer (hereinafter sometimes referred to as a "wafer"), and after patterning by exposure, a liquid treatment such as development is performed. When developing, a puddle (liquid pool) of developer is formed on the substrate for development.

[0009] In this case, if the in-plane temperature of the substrate during paddle development is non-uniform, the uniformity of the line width dimensions of the pattern after development deteriorates. That is, for example, during paddle development, there is a difference in temperature variation from the center part to the edge part of the substrate, and as a result, variations occur in the line width of the pattern from the center part to the edge part of the substrate. Especially in the case of i-line resists with high temperature sensitivity during the development process, this tendency was prominent.

[0010] In the technology described in Patent Document 1, at least a part of the developer piping leading to a nozzle that mixes the developer and air and ejects a mist-like developer is arranged in the circulation path of temperature-controlled water, but there is room for improvement in the in-plane temperature uniformity during paddle development.

[0011] Therefore, the technology according to the present disclosure controls the temperature distribution within the substrate plane when forming a paddle on the substrate and developing the substrate. As a result, liquid treatments such as development can be controlled for each region, and for example, it becomes possible to improve the uniformity of the line width within the substrate plane after development.

[0012] Hereinafter, the configuration of the developing apparatus 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 descriptions are omitted.

[0013] FIG. 1 schematically shows a side cross-sectional view of the configuration of a developing apparatus 1 as a liquid processing apparatus according to the present embodiment. The developing apparatus 1 has a spin chuck 11 as a substrate holding unit in a housing 10. The spin chuck 11 horizontally holds a wafer W as a substrate. The spin chuck 11 is connected to a rotatable elevating unit 12, and the rotatable elevating unit 12 is connected to a rotation driving unit 13 configured by a motor or the like. Therefore, the wafer W held by the driving of the rotation driving unit 13 can rotate.

[0014] A cup 21 is disposed outside the spin chuck 11 to prevent the scattered developing solution, cleaning solution, and their mists from scattering around. A drain pipe 23 and an exhaust pipe 24 are provided at the bottom 22 of the cup 21. The drain pipe 23 communicates with a draining device 25 such as a drain pump. The exhaust pipe 24 communicates with an exhausting device 27 such as an exhaust pump via a valve 26. With such a configuration, the atmosphere around the wafer W held by the spin chuck 11 is exhausted from the exhaust pipe 24. Therefore, the exhaust pipe 24 and the exhausting device 27 constitute an exhaust unit.

[0015] An air blower 14 is provided above the housing 10 of the developing apparatus 1 to supply air at required temperature and humidity as a downflow toward the inside of the cup 21.

[0016] When forming a paddle of the developing solution on the wafer W, a developing solution nozzle 31 is used. The developing solution nozzle 31 is provided on a nozzle support unit 32 such as an arm, for example. The nozzle support unit 32 is movable up and down like a reciprocating arrow A (Z direction) shown by a broken line in the figure and horizontally movable like a reciprocating arrow B (X direction) shown by a broken line by a driving mechanism (not shown). The developing solution is supplied to the developing solution nozzle 31 from a developing solution supply source 34 via a supply pipe 33.

[0017] When forming the paddle, in the case of using a so-called long nozzle having a discharge port with a length equal to or greater than the diameter of the wafer W, a paddle of the developing solution can be formed on the wafer W by scanning from one end to the other end on the wafer W. In the case of a so-called straight type nozzle that discharges a liquid column with a width sufficiently smaller than the diameter of the wafer W, the discharge port is positioned above the center of the wafer W, and while rotating the wafer W, the developing solution is discharged to diffuse the developing solution over the entire surface of the wafer W, thereby forming a paddle of the developing solution on the wafer W. Further, the formation of the paddle of the developing solution may be performed by scanning the straight type nozzle on the wafer W in the same manner as the long nozzle, or by arranging a plurality of discharge ports for discharging the liquid in the same manner as the straight type on the wafer W and supplying the developing solution from each discharge port.

[0018] The spray nozzle 41 has a nozzle body 42. The nozzle body 42 is provided on a nozzle support portion (not shown) such as an arm, and the nozzle support portion is vertically movable like the reciprocating arrow C (Z direction) shown by the broken line in the figure by a drive mechanism (not shown), and is also horizontally movable like the reciprocating arrow D (X direction) shown by the broken line.

[0019] The spray nozzle 41 in the embodiment has a spray portion 43 and a cleaning liquid supply nozzle 44. Then, a liquid and a gas supplied from a supply source 45 of a liquid that does not promote development, for example, water, and a supply source 46 of a gas (for example, an inert gas such as clean air or nitrogen gas) used when spraying are mixed in a mixing portion 47, supplied to the spray portion 43, and a mist of the liquid is sprayed from the spray portion 43. A cleaning liquid is supplied to the cleaning liquid supply nozzle 44 from a cleaning liquid supply source 48. The cleaning liquid supply nozzle 44 is used when cleaning the developing solution on the wafer W after development. As the gas used for spraying, an inert gas is more preferable so as not to inadvertently affect the liquid treatment.

[0020] The developing device 1 is controlled by a control device 100 which is a control unit. The control device 100 is a computer equipped with, for example, a CPU, a memory, etc., and has a program storage unit (not shown). Various programs for controlling the development process of the wafer W in the developing device 1 are stored in the program storage unit. Note that the above programs may be recorded on a computer-readable storage medium and installed from the storage medium into the control device 100. The storage medium H may be a temporary storage medium or a non-temporary storage medium.

[0021] Examples of control include a series of processes from development to cleaning and drying. For example, the movement of the developer nozzle 31 and the spray nozzle 41, the start and stop of spraying from the spray unit 43, the supply and stop of the cleaning liquid from the cleaning liquid supply nozzle 44, the rotation and stop of the spin chuck 11, a series of sequences of the development process, and further, the operations of the air blower 14, the drain device 25, the valve 26, and the exhaust device 27 are also controlled.

[0022] Next, a developing method using the developing device 1 having the above configuration will be described with reference to FIGS. 2(a) to (e). This developing method is an example in which a so-called long nozzle having a discharge port with a length equal to or greater than the diameter of the wafer W is used as the developer nozzle 31. First, while the developer nozzle 31 supplies the developer onto the wafer W held on the spin chuck 11, the wafer W is scanned horizontally from one end to the other end on the wafer W (FIG. 2(a)). As a result, a paddle K of the developer is formed on the wafer W, and the wafer W is developed in a stationary state (FIG. 2(b)). When the paddle K is formed, the developer nozzle 31 retracts to the standby position.

[0023] Thereafter, as shown in FIG. 2(c), the spray nozzle 41 moves in the direction of the center of the wafer W and stops at a predetermined position. The predetermined position in this case is a place where the spray unit 43 is located above the center of the wafer W.

[0024] Then, as shown in Fig. 2(d), water is sprayed from the spray part 43 of the spray nozzle 41 onto the paddle K on the wafer W as a liquid that does not promote development. When water is sprayed, the water mist vaporizes immediately before reaching the paddle K, and the temperature of the surface of the paddle K decreases due to the latent heat of vaporization at that time (temperature control process). In this case, the spin chuck 11 may or may not be rotated. Details such as the spraying timing and the number of sprays will be described later.

[0025] After the in-plane temperature control of the paddle K by spraying from the spray part 43 of the spray nozzle 41 is completed, as shown in Fig. 2(e), the spray nozzle 41 moves, and the center of the cleaning liquid supply nozzle 44 moves onto the center of the wafer W and stops. Thereafter, while rotating the wafer W, the cleaning liquid F is supplied from the cleaning liquid supply nozzle 44 toward the center of the wafer W, so that the developing solution that formed the paddle K is shaken off, and the surface of the wafer W is cleaned by the cleaning liquid F.

[0026] The developing process shown in Fig. 2 was an example in which a long nozzle having a discharge port with a length equal to or greater than the diameter of the wafer W was used for the developing solution nozzle 31. However, when the straight type nozzle described above is used for the developing solution nozzle 31, only the process of forming the paddle K at first is different. That is, while rotating the wafer W, the developing solution is supplied toward the center of the wafer W, and the supplied developing solution is diffused over the entire surface of the wafer W by centrifugal force to form the paddle K. And the process after paddle formation is the same as that shown in Figs. 2(b) to (e) above. In this case, when discharging using a straight type nozzle as the developing solution nozzle 31, when a plurality of discharge ports are arranged side by side on the wafer W to supply the developing solution, the plurality of discharge ports may be arranged in the depth direction at a position overlapping the developing solution nozzle 31, and they may be moved integrally like the developing solution nozzle 31.

[0027] Incidentally, according to the inventors' findings, regarding the in-plane temperature distribution of the paddle K, it has been found that the temperature drop is greater at the peripheral part than at the central part. Explaining this based on the figure, FIG. 3 shows the temperature changes at the central part and the peripheral part of the wafer W after the formation of the paddle K of the developing solution. In the figure, the thick line indicates the temperature change at the central part, and the thin line indicates the temperature change at the peripheral part. It is considered that the reason why the temperature drop at the peripheral part is greater than that at the central part is that exhaust is being performed from the outside of the peripheral part of the wafer W. And when the temperature drop at the peripheral part is greater than that at the central part in this way, it affects the uniformity of the development process, and the line width of the pattern after development becomes non-uniform.

[0028] Therefore, for example, as shown in FIG. 4, when the liquid described above is sprayed from the spraying part 43 of the spray nozzle 41 toward the paddle at the time when 15 seconds have elapsed after the formation of the paddle (S in the figure), the temperature drop rate at the central part of the wafer W is promoted more than in the case of FIG. 3, and then it was confirmed that the temperature difference T between the central part and the peripheral part of the wafer W at the time when 60 seconds have elapsed after the formation of the paddle becomes smaller than that in FIG. 3. As a result of actual measurement, the temperature difference T between the central part and the peripheral part after 60 seconds in FIG. 3 is about 1.2 °C, whereas in the example of FIG. 4 where spraying was performed, the temperature difference T between the central part and the peripheral part after 60 seconds is about 0.5 °C, which is less than half.

[0029] In this way, it was confirmed that by spraying the liquid in a conical shape from above the center of the surface of the paddle K after the formation of the paddle K, the temperature of the central part of the paddle K can be lowered. In the above-described example, the total spraying amount was 2.5 ml. More specifically, FIG. 4 shows an example in which spraying was performed 25 times with a spray nozzle 41 that sprays 0.1 ml each time. Also, the spraying height (the height from the surface of the paddle K to the spray opening of the spraying part 43) was 150 mm. Considering the function of lowering the temperature of the paddle K on the surface of the wafer W by the heat of vaporization, it is preferable that all of the mist of the sprayed liquid vaporizes immediately before the surface of the paddle K. Therefore, it is preferable to determine the spraying amount, the spraying height, and further the particle size of the mist to be sprayed from this point of view.

[0030] From such a perspective, it is considered preferable that the spray amount is 0.1 ml to 0.5 ml per spray, the spray height is 12 mm to 150 mm, and the particle size of the mist is, for example, 0.1 μm to 5.0 μm. Even when the spray height is at a position relatively close to the substrate, such as 12 mm, it is preferable that the liquid to be sprayed is sufficiently diffused radially and vaporized before reaching the wafer W or the paddle K. In addition, since the liquid sprayed from the spray portion 43 of the spray nozzle 41 in the present embodiment is a liquid that does not promote development, even if the mist of the liquid adheres to the surface of the paddle K to some extent, it will not significantly affect the development process.

[0031] As a result of further investigation, it was found that after the formation of the paddle K, during the development process, the temperature sensitivity is greater when spraying in the first half of the process. Therefore, to control the temperature of the paddle K by spraying, it is more suitable to perform it in the first half of the process.

[0032] Alternatively, a liquid obtained by diluting the developer may be sprayed from the spray portion 43 of the spray nozzle 41. By doing so, even if the mist at the time of spraying adheres to the paddle K, almost no change in the concentration of the developer is observed, and thus the influence on the development process can be further suppressed. The technology described in Patent Document 1 adjusts the temperature by warming the discharged air. However, according to the inventor's findings, even if air at 18°C to 28°C is blown onto the development paddle, as long as the development paddle exists, there is almost no influence on the wafer W, and it has been found that the temperature cannot be controlled. In this regard, in the technology of the present disclosure, even after the paddle is formed, since a mist that is easy to vaporize is sprayed, the temperature of the spray area can be quickly lowered, and the development process can be controlled by temperature. Moreover, in the technology of the present disclosure, such temperature adjustment is performed while advancing the development process with the developer on the paddle. Of course, temperature adjustment of the mist of the liquid to be sprayed is not required.

[0033] Also, in the above example, after forming the paddle K of the developing solution on the surface of the wafer W, the solution was sprayed onto the paddle. However, this is not the only way. The above liquid may be directly sprayed onto the wafer W before forming the paddle K. Also, the number of sprayings may be not just once but multiple times.

[0034] FIG. 5 shows the temperature changes at the center and the periphery of the wafer W when it is sprayed once at the 10 - second mark with respect to the wafer W on which the paddle K is not formed. In the figure, the thick line indicates the temperature change at the center and the thin line indicates the temperature change at the periphery. In this case, the temperature at the periphery is higher than the temperature at the center. This is because the paddle K is not formed, so the temperature of the wafer W is constant near the ambient temperature of the apparatus (usually 23°C). In this state, for example, when spraying from a position where the spray height is 75 mm, there are places where the mist does not reach the periphery of the wafer W. Therefore, the peripheral temperature, which is larger in area, becomes about 23°C when the data is averaged.

[0035] On the other hand, FIG. 6 shows the temperature changes at the center and the periphery of the wafer W when spraying is performed three times at the 10 - second mark. In the figure, the thick line indicates the temperature change at the center and the thin line indicates the temperature change at the periphery. Thus, by spraying the wafer W multiple times, the temperature can be lowered more than in the case of single spraying shown in FIG. 5 for both the center and the periphery. However, since spraying is performed from above the center of the wafer W, the mist tends to gather at the center part and form a liquid pool, making it difficult for evaporation to be promoted. As a result, the temperature drop is not large considering the number of sprayings. Also, since there is no processing liquid such as a developing solution on the wafer W, by spraying pure water as the liquid, even if the mist of pure water adheres to the wafer surface, it will not affect subsequent liquid processing such as development.

[0036] In the above example, the spraying section 43 of the spray nozzle 41 was positioned above the center of the wafer W for spraying. However, it is not limited to this, and as shown in FIG. 7, spraying may be performed from above a position eccentric from the center of the wafer W. As described above, after the formation of the paddle K, the temperature drop at the peripheral portion of the wafer W is greater. In such a case, as shown in FIG. 8, the area to be sprayed from the spraying section 43 is preferably sprayed onto an area including the center P of the wafer W.

[0037] Even in such a case, it is not necessary to drive the spin chuck 11 to always rotate the wafer W, and thereby it is possible to lower the temperature of a specific area of the paddle K. For example, when the resist on the wafer W is an i-line resist, it is known that the development process proceeds better at a lower temperature. Therefore, by lowering the temperature of a specific area, the development process can be promoted. Utilizing this, the following temperature control becomes possible. For example, when forming the paddle K of the developer, when supply starts from one end of the wafer W, the development process proceeds more at the one end than at the other end which is the supply end point. To correct this, it is also possible to perform a process such as spraying the other end to lower the temperature than the one end, promoting the development process at the one end, and catching up with the progress of the development process at the other end.

[0038] Also, from such a viewpoint, as shown in FIG. 9, when spraying the spraying section 43 of the spray nozzle 50 obliquely onto the wafer W held by the spin chuck 11, it may be sprayed obliquely from the vertical direction of the center of the wafer W. In such a case, the spin chuck 11 may or may not be rotated. That is, it may be appropriately selected according to the area where the temperature is desired to be lowered.

[0039] The above-described spray nozzle 41 had one spraying section, but it is not limited to this, and it may have a plurality of spraying sections, for example, two spraying sections 43a and 43b, like the spray nozzle 50 shown in FIG. 10.

[0040] That is, the spray nozzle 50 shown in FIG. 10 has a spray part 43a for spraying the central part of the wafer W and a spray part 43b for spraying the peripheral part of the wafer W. By using a spray nozzle having such a configuration, for example, each spray part 43a, 43b can be controlled by the control device 100 so as to spray the central part of the wafer W for a longer time than the peripheral part. Thereby, it is possible to spray the central part of the wafer W for a longer time and make the temperature drop larger than that of the peripheral part.

[0041] Furthermore, it is possible to spray only the central part and stop spraying on the peripheral part or spray with a spray amount less than that of the central part. Thereby, the temperature control for each region of the wafer W by spraying can be performed more finely.

[0042] In the above-described example, the flow rate of the spray from the spray part of the spray nozzle has not been particularly described. However, after the formation of the paddle K, since the development process is in progress, it is preferable to spray at a flow rate such that the surface of the wafer W is not exposed by the spray. This is because if the surface is exposed, the development process of the exposed part stops.

[0043] Note that the exhaust volume while spraying from the spray nozzles 41 and 50 is smaller than the exhaust volume when cleaning the wafer W after the liquid treatment. After the liquid treatment, there is no need to pay special attention to the temperature within the plane of the wafer W. On the other hand, a large amount of mist of the cleaning liquid is generated during cleaning, so it is necessary to exhaust this quickly. Also, during spraying, it is possible to perform suitable temperature control without disturbing the spray flow.

[0044] Also, the above-described spray nozzle 41 has a configuration in which the spray part 43 and the cleaning liquid supply nozzle 44 are integrated, but it may have a configuration separate from the cleaning liquid supply nozzle like the spray nozzle 50.

[0045] The above-described example is particularly effective for the development of an i-line resist sensitive to temperature. Of course, the present disclosure is not limited to this, and is also effective for the development of a resist exposed by an energy beam such as g-line, KrF excimer laser, ArF excimer laser, etc.

[0046] The embodiments disclosed this time should be considered illustrative in all respects and not restrictive. The above embodiments may be omitted, replaced, or changed in various forms without departing from the scope and gist of the appended claims.

Description of Reference Numerals

[0047] 1 Developing device 10 Housing 11 Spin chuck 12 Rotating part 13 Rotation drive part 14 Blower 21 Cup 22 Bottom 23 Drain pipe 24 Exhaust pipe 25 Drainage device 26 Valve 27 Exhaust device 31 Developer nozzle 32 Nozzle support part 41, 50 Spray nozzles 42 Nozzle body 43, 43a, 43b Spray parts 44 Cleaning liquid supply nozzle 100 Control device F Cleaning liquid K Paddle W Wafer

Claims

1. A liquid processing apparatus for performing liquid processing on a substrate with a processing liquid, comprising: a substrate holding unit that holds and rotates the substrate; a spray nozzle located above the substrate held by the substrate holding unit, for spraying a liquid that does not promote the liquid processing onto a region in the plane of the substrate including the center of the substrate; the liquid processing is a development process, the processing liquid is a developer, and the liquid is water; a liquid processing apparatus that controls the temperature of the substrate or the developer on the substrate by the heat of vaporization of the water sprayed by the spray nozzle.

2. having a control unit for controlling the spray nozzle; The liquid processing apparatus according to claim 1, wherein the control unit is configured to spray the liquid from the spray nozzle at least in the first half of the development processing time with the developer after forming a paddle of the developer on the surface of the substrate.

3. A liquid processing apparatus for forming a paddle of a developer, which is a processing liquid, on a substrate and developing the substrate, comprising: a substrate holding unit that holds and rotates the substrate; a spray nozzle located above the substrate held by the substrate holding unit, for spraying a liquid obtained by diluting the developer onto a region in the plane of the substrate including the center of the substrate; a control unit for controlling the spray nozzle; and a liquid processing apparatus that controls the temperature of the substrate or the developer on the substrate by the heat of vaporization of the liquid sprayed by the spray nozzle.

4. The liquid processing apparatus according to any one of claims 2 or 3, wherein the control unit is configured to spray the spray nozzle a plurality of times during the development processing with the developer.

5. having a control unit for controlling the spray nozzle; The liquid processing apparatus according to claim 1, wherein the control unit is configured to spray the liquid onto a region in the plane of the substrate including the center of the substrate before the processing liquid is supplied onto the substrate by the spray nozzle.

6. The spray nozzle has a spray portion for spraying on the central portion of the substrate and another spray portion for spraying on the peripheral portion of the substrate; The liquid processing apparatus according to any one of claims 2 to 5, wherein the control unit is configured to spray for a longer time on the central portion than on the peripheral edge portion of the surface of the substrate.

7. The spray nozzle has a spray portion for spraying on the central portion of the substrate and another spray portion for spraying on the peripheral portion of the substrate; The liquid processing apparatus according to any one of claims 2 to 5, wherein the control unit is configured to spray the central portion of the surface of the substrate while not spraying the peripheral portion of the surface of the substrate.

8. When being sprayed toward the paddle of the processing liquid formed on the substrate while the liquid processing is in progress on the surface of the substrate, the spraying is performed at a flow rate such that the surface of the substrate is not exposed by the spraying. The liquid processing apparatus according to any one of claims 2 to 7.

9. The liquid processing apparatus further includes an exhaust unit configured to exhaust the atmosphere around the substrate held by the substrate holding unit. The control unit is configured to control the exhaust unit such that an exhaust amount during spraying of the liquid from the spray nozzle is smaller than an exhaust amount during cleaning of the substrate after the liquid processing of the substrate is completed. The liquid processing apparatus according to any one of claims 2 to 8.

10. When spraying from the spray nozzle onto the substrate held by the substrate holding unit, the spraying is performed while being inclined obliquely from the vertical direction of the center of the substrate. The liquid processing apparatus according to any one of claims 1 to 9.

11. A liquid processing method for performing liquid processing on a substrate, spraying a liquid onto a region within the plane of the substrate including the center of the substrate from above the substrate holding unit that holds and rotates the substrate, controlling the temperature of the substrate or the processing liquid on the substrate by the heat of vaporization of the sprayed liquid. A liquid processing method.

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