JP7624356B2 - Developing device and developing method - Google Patents

Description

This disclosure relates to a developing device and a developing method.

Patent document 1 discloses a spin developer that supplies a rinse liquid from a rinse nozzle to an object to be cleaned after development processing to clean the developer, and is characterized by having a first nozzle that causes the rinse liquid to flow to the center of the object to be cleaned, and a second nozzle that causes the rinse liquid to flow to the periphery of the object to be cleaned. This document also describes that the developer is dripped from above the center of the wafer.

Japanese Patent Application Publication No. 2-62549

The technology disclosed herein prevents overdevelopment and pattern peeling in the center of the substrate.

One aspect of the present disclosure is a developing apparatus for developing a substrate, the developing apparatus comprising: a rotating support part for rotating the substrate around a center of the substrate; a developing nozzle for supplying a developing solution to a surface of the substrate on the rotating support part; a nozzle moving mechanism for moving the developing nozzle at least horizontally above the substrate; and a control part for controlling the supply of developing solution from the developing nozzle, the rotating support part, and the nozzle moving mechanism, wherein the control part is configured to repeatedly perform the following steps A and B.
Step A: While rotating the substrate at a first speed, the developer is supplied from the developing nozzle at a first position off the center of the substrate to form an annular liquid film of the developer on the surface of the substrate.
Step B: While rotating the substrate at a second speed slower than the first speed, the developing nozzle supplies the developer at the first position, and the developer spreads over the substrate when supplied to the substrate to cover the center of the substrate.

This disclosure makes it possible to prevent overdevelopment and pattern peeling in the center of the substrate.

1 is a side cross-sectional view that illustrates a schematic configuration of a developing device according to an embodiment of the present invention. FIG. 2 is a plan view showing a schematic outline of the configuration of the developing device shown in FIG. 1 . 1A to 1C are perspective views showing a process of a developing method according to an embodiment of the present invention. 10A to 10C are perspective views showing a process of a developing method according to another embodiment. 11 is a flowchart showing two loops of the process of the developing method according to the embodiment. 1 is a graph showing the relationship between the position on a wafer and the line width of a pattern when the wafer is developed by a conventional developing method. 10A to 10C are perspective views showing a process of a developing method according to another embodiment. 9 is a graph showing the relationship between the position on a wafer and the line width of a pattern when the wafer is developed by the developing method of FIG. 8 . FIG. 13 is a side view showing a state in which the developing nozzle is moved toward the outer periphery above the wafer.

For example, in the manufacturing process of semiconductor devices, a development process is performed in which a resist film is formed on the surface of a substrate such as a semiconductor wafer (hereinafter sometimes referred to as a "wafer"), a pattern is exposed to light, and then development is performed as a liquid process. When developing, as disclosed in Patent Document 1, a developer is supplied from above the center of the substrate while rotating the substrate, and the developer is diffused by centrifugal force to cover the entire surface of the substrate.

With this type of development method, new developer is constantly being supplied to the center of the substrate, which can lead to overdevelopment in the center, resulting in poor in-plane uniformity of the pattern, or the pressure exerted on the substrate surface when developer is supplied from the development nozzle can cause the pattern to peel off.

The technology disclosed herein prevents overdevelopment and pattern peeling in the center of the substrate when developing the substrate by supplying developer to the substrate while rotating it.

The configuration of the developing device according to this embodiment will be described below with reference to the drawings. Note that in this specification, elements having substantially the same functional configuration will be assigned the same reference numerals to avoid redundant description.

Figure 1 shows a side cross-sectional view that shows a schematic overview of the configuration of the developing device 1 according to this embodiment. The developing device 1 has a spin chuck 11 as a substrate holding unit inside a housing 10. The spin chuck 11 holds a wafer W as a substrate horizontally. The spin chuck 11 is connected to a rotating unit 12 that can be raised and lowered, and the rotating unit 12 is connected to a rotation drive unit 13 that is constituted by a motor or the like. Therefore, the held wafer W can be rotated by driving the rotation drive unit 13.

A cup 21 is placed outside the spin chuck 11 to prevent the developer, rinse liquid, and mist thereof 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 is connected to a drainage device 25 such as a drainage pump. The exhaust pipe 24 is connected via a valve 26 to an exhaust device 27 such as an exhaust pump. With this configuration, the atmosphere around the wafer W held by the spin chuck 11 is exhausted from the exhaust pipe 24. The exhaust pipe 24 and the exhaust device 27 form an exhaust section.

An air blower 14 is provided at the top of the housing 10 of the developing device 1 to supply air at the required temperature and humidity as a downflow into the cup 21.

The developing nozzle 31 that supplies the developing solution onto the wafer W is provided on the nozzle support part 32. The nozzle support part 32 is also provided with a rinsing nozzle 33. The developing nozzle 31 and the rinsing nozzle 33 are arranged in a straight line in the X direction.

As shown in FIG. 2, the nozzle support 32 is attached to an arm 41, which is connected to a moving mechanism 42. The moving mechanism 42 moves in the X direction along a guide rail 43 extending laterally, and can raise and lower the arm 41 (movement in the Z direction). The moving mechanism 42 moves in accordance with a control signal from a control device 100, which will be described later. This movement of the moving mechanism 42 allows the nozzle support 32 to move between a standby position outside the cup 21 and the center of the wafer W, and to stop at a desired position. The moving distance, moving speed, and moving direction of the moving mechanism 42 are also controlled by a control signal from the control device 100.

The developing nozzle 31 is connected to a developing solution supply source 53 via a valve 51 and a pump 52. The rinsing nozzle 33 is connected to a rinsing solution supply source 56 via a valve 54 and a pump 55.

The developing device 1 is controlled by a control device 100, which is a control unit. The control device 100 is, for example, a computer equipped with a CPU, memory, etc., and has a program storage unit (not shown). The program storage unit stores various programs that control the developing process of the wafer W in the developing device 1. The above programs may be recorded on a computer-readable storage medium and installed from the storage medium into the control device 100. It does not matter whether the storage medium H is a temporary storage medium or a non-temporary storage medium.

Examples of control include a series of processes from development to cleaning and drying. For example, a series of sequences of development processes are controlled, including the movement and stopping of the nozzle support part 32, the supply and stopping of developer from the development nozzle 31, the rotation and stopping of the spin chuck 11, control of the rotation speed, the supply and stopping of rinse solution from the rinse nozzle 33, etc.

Next, a developing method using the developing apparatus 1 having the above configuration will be described with reference to Figs. 3(a) to (d). The following example will be described based on a developing process for a negative type resist. First, the wafer W held on the spin chuck 11 is rotated at a first speed, and the nozzle support 32 is moved toward the center P of the wafer W and stopped at a first position, which is a predetermined position (Fig. 3(a)). Here, the first speed is a relatively high speed rotation (indicated by the arrow HI indicating the rotation direction in the figure), for example, 500 rpm. The first speed is preferably 500 rpm or less, and preferably 300 rpm to 500 rpm. The first speed is faster than the second speed (relatively low speed rotation) described later, so the preferred rotation speed is faster than the second speed.

In this example, the first position, which is a predetermined position, is a position where the discharge port of the development nozzle 31 is located at a horizontal distance D1 of 30 mm from the center P of the wafer W. Of course, this is not limited to this, and the distance D1 may be set in the range of, for example, 20 mm to 40 mm.

Next, at the first position, the developer is supplied from the developing nozzle 31 to the wafer W. The supply time is, for example, 2 to 10 seconds. As a result, a circular area not covered with the developer is formed on the wafer W as shown in FIG. 3(b) (step A in this disclosure). In other words, the developer discharged onto the surface of the wafer W while the wafer W is rotating is spread by centrifugal force, while the developer discharged onto the surface of the wafer W spreads in a circular shape around the landing point on the surface of the wafer W. When the centrifugal force is greater than the circular spread on the wafer W, a circular area not covered with the developer is formed as shown in FIG. 3(b), and the developer forms a liquid film of the developer in a ring shape around the center P of the wafer W.

3(c), while the discharge position of the developing nozzle 31 is kept at the first position, the rotation speed of the wafer W is rotated at a second speed (indicated by the symbol Lo in the figure) slower than the first speed, for example, 40 rpm, while the developer continues to be supplied to the surface of the wafer W (step B in this disclosure). Then, as the rotation speed decreases, the centrifugal force decreases, and the developer supplied to the surface of the wafer W spreads more when the developer lands on the surface than the centrifugal force, spreading to the center of the wafer W including the center P of the wafer W, and the center of the wafer W is covered with the developer. The second speed may be any speed at which the developer spreads more when the developer lands on the surface than the centrifugal force caused by the rotation of the wafer W, for example, 10 rpm to 50 rpm.

The supply time can be, for example, 10 to 50 seconds (when multiple LOOPs are not set, as described below), but can be set appropriately in relation to the second speed. For example, it can be appropriately set based on the residence time of the developer at the center of the wafer W as it spreads to the center, that is, the development time. For example, if the development time is 60 seconds, when the developer is supplied for 10 seconds at the first speed, it can be supplied for 50 seconds at the second speed. Also, since the developer continues to be supplied from the development nozzle 31 in step B, pattern collapse caused by the sudden movement of the developer on the wafer W due to a sudden deceleration in the rotation speed of the wafer W, known as pullback, does not occur.

After that, the discharge of the developing solution is stopped, and as shown in FIG. 3(d), the nozzle support 32 is moved toward the center P and stopped at a position where the distance R from the center P of the wafer W to the discharge port of the rinse nozzle 33 is, for example, 10 mm. Then, at this position, a rinse solution, for example, pure water, is supplied to the wafer W from the rinse nozzle 33. At this time, since the discharge position of the rinse solution is closer to the center P than the above-mentioned distance D1, the rotation speed of the wafer W need only be equal to or higher than the first speed. The distance R can be, for example, 5 mm to 10 mm.

According to the developing method of this embodiment, the developer is supplied at a position away from the center P of the wafer W, and the developer is not continuously supplied to the center position of the wafer W as in the conventional method. Therefore, the occurrence of pattern peeling at the center of the wafer W is suppressed. In other words, by performing a step in which the developer is not supplied directly from the developing nozzle 31 to the center P of the wafer W during the developing process, the degree and progress of development at the center of the wafer W can be controlled.

The inventors have found that pattern peeling is correlated with the integrated value of the pressure (liquid pressure) when the developer is supplied. Therefore, by adopting a process and step in which the developer is not supplied directly to the center of the wafer W as in the above-described embodiment, the integrated value of the liquid pressure at the center of the wafer W can be reduced, and the occurrence of pattern peeling during development can be significantly suppressed.

In addition, since the developer reaches the center of the wafer W after the wafer W is rotated at the second speed in step B of the present disclosure, the time that the developer remains in the center, i.e., the developing time, is shorter than in conventional developing methods in which developer is constantly supplied to the center. Therefore, it is possible to suppress overdevelopment in the center of the wafer W, which was previously observed.

Furthermore, in the above embodiment, the position where the rinse liquid is supplied by the rinse nozzle 33 is also off the center P of the wafer W, so it is possible to prevent pattern peeling and pattern collapse at the center of the wafer W due to the supply of the rinse liquid.

In the above embodiment, step A is performed in which the wafer W is rotated at a first speed, followed by step B in which the developer is supplied at a second rotation speed slower than the first rotation speed. However, step B may be performed first, followed by step A.

Figure 4 shows the process in this case, where the wafer W held on the spin chuck 11 is rotated at a second speed, the nozzle support 32 is moved toward the center P of the wafer W, and stopped at a first position, which is a predetermined position (Figure 4(a)), and then, as shown in Figure 4(b), while the wafer W is rotating at the second speed, developer is supplied to the wafer W from the developing nozzle 31 at the first position. The supplied developer then spreads to cover the central portion of the wafer W, including the center P.

Next, as shown in FIG. 4(c), the wafer W is rotated at a first speed that is faster than the second speed. Then, since the developer is supplied onto the wafer W at a position away from the center P of the wafer W, the developer in the center also flows toward the outer periphery of the wafer W due to centrifugal force, and a ring-shaped liquid film of the developer is formed on the wafer W. After that, the supply of the developer is stopped, the nozzle support 32 is moved toward the center of the wafer W, the outlet of the rinse nozzle 33 is positioned at a distance R from the center P of the wafer W, and the rinse liquid is supplied to the wafer W from the rinse nozzle 33 to clean the wafer W (FIG. 4(d)).

In this way, step B in the present disclosure is performed first to perform the development process of at least the center of the wafer W, and then step A in the present disclosure is performed. This makes it possible to appropriately respond to the development process of resists in which the overall development process is dominated in the first half of the development, such as KrF resists and ArF resists, in other words, development processes in which the sensitivity differs between the first and second halves of the development process, and to suitably control the development of the center of the wafer W.

In the embodiment of FIG. 3 described above, step A (FIG. 3(b)) is followed by step B (FIG. 3(c)), after which a cleaning step (FIG. 3(d)) is performed by supplying a rinsing liquid. However, steps A and B may be repeated.

The flowchart in Figure 5 shows the process in such a case. First, LOOP1 is explained. The wafer W is rotated at a first speed (step S1), the developer is discharged at a first position (step S2), and the wafer W is rotated at a second speed while the developer is still being discharged (step S3). Thereafter, the supply of the developer is stopped (step S4). In the example shown in Figure 3, the wafer W is then cleaned by supplying a rinse liquid.

In the example shown in FIG. 5, after the supply of the developing solution is stopped, the developing solution is replaced and fresh developing solution is newly supplied by rotating the wafer W to shake off the developing solution on the wafer W (step S5). Next, as LOOP2, the wafer W is rotated at a first speed (step S6), the developing solution is discharged at the first position (step S7), the wafer W is rotated at a second speed while still discharging the developing solution (step S8), and then the supply of the developing solution is stopped (step S9). That is, steps A and B in this disclosure are repeated. After that, a rinsing solution is supplied to clean the surface of the wafer W (step S10), and then the supply of the rinsing solution is stopped, and the wafer W is rotated to so-called shake off and dry the wafer W (step S11).

In this manner, by repeatedly performing steps A and B in the present disclosure, the range for controlling the degree of development of the central portion of the wafer W is expanded. That is, for example, by adjusting the time of step S2 in LOOP1 and the time of step S7 in LOOP2, or by making them different times, it is possible to control the degree and progress of development of the central portion of the wafer W, and to efficiently perform the development process by supplying fresh developer in LOOP2.

However, in the conventional method of developing by constantly supplying developer to the center of the wafer W while rotating the wafer W, as mentioned above, the center of the wafer W is prone to overdevelopment. As a result, as shown in Figure 6, the line width of the pattern tends to be narrower in the center and wider toward the periphery, leaving room for improvement in the uniformity of the development process within the substrate surface.

From this perspective, for example, the process shown in FIG. 7 can be proposed. That is, in the above-mentioned step B, initially, as shown in FIG. 7(a), the wafer W is rotated at a second speed while developer is supplied from the developing nozzle 31 to the wafer W at a first position (e.g., distance D1 = 30 mm). Then, as shown in FIG. 7(b), the developing nozzle 31 is moved to a second position (e.g., distance D2 = 60 mm) on the outer periphery while maintaining the second speed.

After that, for example, after 5 seconds have elapsed, the developing nozzle 31 is moved to a third position (e.g., D3 = 90 mm) on the outer periphery side as shown in FIG. 7(c) while maintaining the second speed. In this way, development from the center P of the wafer W to the intermediate portion can be suppressed in stages. As a result, the line width profile of the wafer W after development can be made generally flatter as shown in FIG. 8, and the in-plane uniformity of the development process can be improved. In such a case, the developing nozzle 31 may be moved continuously instead of in such a stepwise manner.

Furthermore, such movement of the development nozzle 31 may be performed when steps A and B of this disclosure are repeated, i.e., when LOOP1 and LOOP2 are executed, as in the flowchart shown in FIG. 5, in each of LOOP1 and LOOP2, or in either LOOP.

Furthermore, when steps A and B in the present disclosure are repeated three times, i.e., in the case of a process having LOOP1 to LOOP3, in step B of LOOP1, the developer nozzle 31 may be discharged at the position shown in FIG. 7(a) (a position at a distance D1 from the center P of the wafer W), in step B of LOOP2, the developer nozzle 31 may be discharged at the position shown in FIG. 7(b) (a position at a distance D2 from the center P of the wafer W), and in step B of LOOP3, the developer nozzle 31 may be discharged at the position shown in FIG. 7(c) (a position at a distance D3 from the center P of the wafer W). That is, the discharge position may be shifted for each LOOP. With such a process, development from the center P of the wafer W to the intermediate portion can be gradually suppressed, and the line width profile of the wafer W after development can be generally made flatter, as shown in FIG. 8.

The movement of the developing nozzle 31 described above is performed in step B, but in step A as well, the developing nozzle 31 may be moved stepwise or continuously from the center side to the peripheral side to supply the developing solution to the wafer W.

Furthermore, the movement of the developing nozzle 31 described above is stepwise or continuous from the first position toward the periphery as indicated by the arrow M in FIG. 9, but it may also be moved from the periphery toward the center of the wafer W as indicated by the dashed arrow N in FIG. 9. In this case, the rotation speed of the wafer W may be set to a relatively low speed (second speed) when the developing nozzle 31 is located toward the periphery, and a relatively high speed (first speed) when the developing nozzle 31 is located toward the center of the wafer W.

The above example was effective for developing negative-type resist, but it is also effective for positive-type resist.

The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. The above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

REFERENCE SIGNS LIST 1 Developing device 10 Housing 11 Spin chuck 12 Rotating section 13 Rotation drive section 14 Air blowing device 21 Cup 22 Bottom section 23 Drain pipe 24 Exhaust pipe 25 Drain device 26 Valve 27 Exhaust device 31 Developing nozzle 32 Nozzle support section 33 Rinse nozzle 100 Control device P Center W Wafer

Claims (9)

A developing apparatus for developing a substrate, comprising:
a rotation support that rotates the substrate around a center of the substrate;
a developing nozzle for supplying a developing solution to a surface of the substrate on the rotation support;
a nozzle moving mechanism that moves the developing nozzle at least horizontally above the substrate;
a control unit that controls the supply of developer from the developing nozzle, the rotation support unit, and the nozzle movement mechanism,
The control unit is configured to repeatedly execute the following steps A and B.
Step A: While rotating the substrate at a first speed, the developer is supplied from the developing nozzle at a first position off the center of the substrate to form an annular liquid film of the developer on the surface of the substrate.
Step B: While rotating the substrate at a second speed slower than the first speed, the developing nozzle supplies the developer at the first position, and the developer spreads over the substrate when supplied to the substrate to cover the center of the substrate. The developing device of claim 1, in which step B is performed after step A. The developing device of claim 1, in which step A is performed after step B. 4. The developing device according to claim 1, wherein, when the steps A and B are repeatedly performed, the developing nozzle supplies the developer at a second position different from a first position at which the developer is initially supplied. The developing device according to any one of claims 1 to 4 , wherein the first speed is 500 rpm or less. 6. The developing device according to claim 1 , wherein in step A or step B, the developing nozzle is moved from the first position to a peripheral edge side of the substrate while supplying a developer from the developing nozzle. 7. The development apparatus of claim 6 , wherein the movement is stepwise or continuous. a rinse nozzle for supplying a rinse liquid to a surface of the substrate;
a rinse nozzle moving mechanism that moves the rinse nozzle at least horizontally above the substrate;
a control unit that controls the supply of the rinse liquid from the rinse nozzle and the rinse nozzle moving mechanism,
The control unit is
The developing device according to any one of claims 1 to 7, further configured to perform a step of supplying a rinsing liquid to the substrate at a position where the rinse nozzle is off a center of the substrate while rotating the substrate at a second speed slower than the first speed after performing the step A or the step B. A developing method for developing a substrate using a developer, comprising the steps of:
supplying a developer to a first position off the center of the substrate while rotating the substrate at a first speed, thereby forming an annular developer film on a surface of the substrate;
supplying the developer at the first position while rotating the substrate at a second speed slower than the first speed, so that the developer spreads over the substrate when supplied to the substrate to cover a central portion of the substrate;
having
The developing method comprises repeating each of the steps .

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