JP7129204B2 - Paddle type developing device - Google Patents

Description

The present invention relates to a developing apparatus used in a semiconductor integrated circuit manufacturing process and a photomask manufacturing process. More specifically, the present invention relates to a paddle-type developing device which is excellent in uniformity and resolution.

In the photolithography process, which is an important process in semiconductor manufacturing, the photosensitive resist film formed on the substrate is exposed using a photomask or an electron beam lithography device, and then developed to form a resist film pattern. is doing.

Known development processing methods include (1) a dip method, (2) a spray method, and (3) a paddle method.
The dipping method is a method in which the substrate with a photosensitive resist film after exposure is immersed in a developing solution in a developing tank and shaken to perform development.
The spray method is a method in which development is performed by spraying a developing solution from a spray nozzle onto a substrate with a photosensitive resist film after exposure. Usually, the development process is performed while rotating the substrate in order to make the development process uniform.
The paddle system is a scanning type developing device, and nozzles are ejected along the substrate surface from a nozzle head equipped with a slit-shaped developer ejection port to a substrate with a photosensitive resist film after exposure. This is a developing method in which the developer is heaped up by scanning the head. Liquid heaping refers to forming a layer of the developer on the exposed photosensitive resist film-coated substrate so that the edges of the developer have a large contact angle due to surface tension.

As the size of semiconductor patterns becomes finer, the paddle method, which is excellent in development uniformity and resolution, has become mainstream.

However, in such a paddle-type developing device, if the upper surface of the photosensitive resist film after exposure is scanned while the liquid is heaped up, the development will be too strong, resulting in good pattern removal (resolution), but At the same time, there is a problem that pattern collapse is likely to occur.

As a countermeasure, for example, if the development time is shortened, the pattern collapse is reduced, but the pattern removal property is deteriorated. In addition, appearance defects and the like are likely to occur due to resist development residues and the like. Thus, there is a trade-off relationship between pattern resolution and pattern collapse and appearance defects.

As a paddle type developing device capable of suppressing pattern collapse and appearance defects with high pattern resolution, for example, in Patent Document 1, a developer is formed on a spin chuck having a circular guide, While maintaining the paddle state, the spin chuck that holds the substrate performs agitation that temporarily repeats rotation and stop, making it possible to perform the same agitation as in the wafer development process even for photomask quartz substrates. A developing device has been proposed (see FIGS. 4 to 6).

FIG. 4 is a cross-sectional explanatory view illustrating a state in which the spin chuck 12 of the developing unit 50 of the developing device is lifted from the spin chuck accommodating portion 18. As shown in FIG.
The spin chuck 12 includes a connecting portion 4 and a plurality of substrate holding portions 3 that support a substrate 9 to be developed on the connecting portion 4 at its ends.
The board holding portion 3 is connected to and supported by the guide portion 17 . The guide portion 17 is supported by the connecting portion 4 by the guide support portion 16 . The connecting portion 4 connects the driving force from the driving portion 8 to the shaft 7 so that the spin chuck 12 can rotate.
The drive unit 8 is electrically connected to a control device (not shown) and has a motor that rotates according to a control signal from the control device.
The spin chuck housing portion 18 includes a circular guide 6 provided on the peripheral portion of the spin chuck 12 and a recess 5 that is a space formed inside the circular guide 6 .
The concave portion 5 has an outer dimension and a depth that can accommodate the spin chuck 12 . The bottom surface of the concave portion 5 serves as a flat surface for supporting the spin chuck 12 as the spin chuck stage 11 . An upright wall surface 15 is provided between the spin chuck stage 11 and the circular guide 6 , and the recess 5 is formed by the wall surface 15 and the spin chuck stage 11 . The depth of the concave portion 5 is set so that the height of the upper surface of the substrate to be developed 9 and the upper surface of the circular guide 6 are flush with each other when the substrate to be developed 9 is mounted on the substrate holding portion 3 .

5 illustrates a state in which the spin chuck 12 in FIG. 4 is lowered and stored in the spin chuck storage portion 18. FIG. Liquid filling is possible in this state.

FIG. 6 is a top view of FIG. 4 or 5 viewed from above. A liquid developer is not shown. In FIG. 6, the spin chuck holding the substrate 9 to be developed by a plurality of substrate holding portions 3 is accommodated in the concave portion 5 so that the substrate to be developed 9 can be put into the liquid developer. exemplifies the state of

Since the spin chuck 12 is rotated while being held in a liquid-filled state, the spin chuck 12 may be rotated slowly. Therefore, it may start to turn slowly and the final rotational speed may also be kept low. In such a case, there is a problem that the effect of agitating the heaped developer is limited.

Therefore, in the puddle type development method, there is a long-awaited technology that achieves both excellent resolution and suppression of pattern collapse and appearance defects by enabling more effective agitation in the inside of a heaped developer. .

JP 2012-19160 A

In view of the above circumstances, the present invention provides a paddle-type developing device that achieves excellent resolution and suppresses pattern collapse and appearance defects by making it possible to more effectively agitate the inside of a heaped developer. It is an object of the present invention to provide a developing device that satisfies both

As means for solving the above problems, a first aspect of the present invention provides a spin chuck for rotatably holding a substrate to be developed;
A circular guide that is provided outside the spin chuck and causes liquid to swell over the entire target substrate;
and a paddle-type developing device having a stirring unit for stirring a developer in a liquid heaping state.

A conventional paddle-type developing device is a developing device that includes a spin chuck that rotatably holds a substrate to be developed and a circular guide that extends outside the spin chuck so that the developer can be filled. There is no means other than rotating and stopping the spin chuck as means for more effectively agitating the heaped developing solution. Therefore, it was not possible to stir more effectively.
In the first aspect of the present invention, since the stirring unit for stirring the heaped developer is provided, the heaped developer can be actively stirred independently of the rotation of the spin chuck. As a result, portions where the developing speed is slowed down and portions where the developing speed is not slowed down due to local retention of the developer are not formed, and uniform processing of development becomes possible.

A second aspect is the paddle-type developing device according to the first aspect, wherein the agitating unit has a strip-shaped plate that can be scanned in the developer.

A second aspect of the present invention is to agitate the heaped developer by freely scanning a strip-shaped blade such as a doctor blade. By scanning the strip-shaped blade parallel to the main surface of the substrate to be developed and in a direction orthogonal to the longitudinal direction of the strip-shaped blade, stirring of the developer is promoted over a wide range.

In a third aspect, according to the first aspect, the stirring unit is a disk that rotates while being in contact with the liquid surface of the liquid developer or being submerged in the liquid. is a paddle-type developing device.

By rotating the disk, it is possible to obtain a stronger stirring effect than when only a conventional spin chuck is rotated.

Further, according to a fourth aspect, according to the first aspect, the stirring unit is a stator of an ultrasonic motor which is in contact with the liquid surface of the heaped developer or is submerged in the liquid. is a paddle-type developing device.

This method uses a stator portion of an ultrasonic motor as a stirring unit. In this case, this stator forms a traveling wave, which rotates the rotor. In a third aspect, the portion corresponding to the rotor is a liquid developer. As a traveling wave, if a traveling wave that rotates like an ordinary motor is generated, the rotation will cause stirring, so that the same stirring effect as in the third embodiment can be exhibited. If a traveling wave that advances linearly like a linear motor is created, the developer can be moved linearly, so that the same agitating effect as in the second embodiment can be exhibited.

A fifth aspect is the first aspect, characterized in that the stirring unit is means for forming a rotating magnetic field in the heaped developing solution in parallel with the surface of the substrate to be developed. is a paddle-type developing device.

This means is a method that utilizes the fact that the developer is an electrolyte solution and therefore has conductivity. For example, when an alternating magnetic field that changes in the vertical direction is applied to a conductive liquid, a current flows in the conductive liquid in a direction that cancels out the alternating magnetic field (electromagnetic induction phenomenon). When a rotor made of, for example, a permanent magnet is placed in a rotating magnetic field like an ordinary induction motor, the rotor rotates while being attracted or repulsed by the magnetic force of the rotating magnetic field.
Instead of this rotor, if a developer, which is a conductive liquid, is placed in a rotating magnetic field, the developer can be rotated by the rotating magnetic field and stirred.

In the paddle-type developing device of the present invention, the developing liquid heaped on the substrate to be developed held by the spin chuck is stirred independently of the stirring effect in addition to the stirring effect due to the rotation/stopping of the spin chuck. Since the developer is provided with the stirring means capable of performing the above, the developer that is heaped up can be stirred more effectively, and more uniform development can be performed. Therefore, it is possible to achieve both excellent resolution and suppression of pattern collapse and appearance defects.

FIG. 2 is a cross-sectional explanatory view showing a configuration example of a paddle-type developing device according to the present invention; FIG. 2 is a cross-sectional explanatory view showing a configuration example of a paddle-type developing device according to the present invention; FIG. 2 is a cross-sectional explanatory view showing a configuration example of a paddle-type developing device according to the present invention; FIG. 5 is a cross-sectional explanatory view showing a configuration example of a conventional paddle-type developing device. FIG. 5 is a cross-sectional explanatory view showing a configuration example of a conventional paddle-type developing device. FIG. 2 is an explanatory top view showing a configuration example of a conventional paddle-type developing device.

The paddle-type developing device of the present invention includes a spin chuck that rotatably holds a substrate to be developed, a paddle-type developing unit, and an agitating unit that agitates a heaped developer. It is characterized in that it is provided with a stirring unit that stirs the developer liquid heaped up on the substrate to be developed independently of the rotation of the spin chuck.

The paddle type developing device of the present invention will be described in more detail with reference to FIGS. 1 to 3. FIG.

<First embodiment>
FIG. 1 is a cross-sectional explanatory view illustrating a first embodiment of a paddle-type developing device of the present invention.
The paddle-type developing device 10 of the present invention includes a spin chuck 12 (see FIG. 4) that rotatably holds a substrate 9 to be developed, a shaft 7 that rotatably supports the spin chuck 12, and a drive for rotating the shaft 7. 8, and a stirring unit 1-1 for stirring the heaped developer. The spin chuck 12 includes a substrate holding portion 3 for holding a substrate 9 to be developed, and a circular bow-shaped member extending outward from four sides of the substrate 9 to be developed so as to support the side surfaces of each side of the substrate 9 to be developed. and a guide support portion 16 that supports the board holding portion 3 and the guide portion 17 .

In the developing device 10 of the first embodiment, the stirrer unit 1-1 includes a scan stirrer 2-, which is means for scanning a strip-shaped plate in the liquid developer in a direction orthogonal to the longitudinal direction. 1. The strip-shaped plate may be inclined at any angle in the longitudinal direction. In addition, the stirring unit 1-1 is means for scanning the liquid developer in a heaped state parallel to the main surface of the substrate 9 to be developed.

A strip-shaped plate is a plate-shaped article such as a doctor blade. The scan agitating part 2-1 having such a shape moves and scans the developer liquid heaped on the substrate 9 to be developed along the main surface (front surface) of the substrate 9 to be developed. Therefore, the heaped developer is agitated. Localization can be suppressed by stirring the exhausted developer.
In this manner, more uniform development processing can be achieved. The manner in which the scan agitating section 2-1 moves is not particularly limited as long as it is a manner in which the developer can be agitated so that uniform development processing is possible. It may move linearly or may rotate. It is also good to do a movement that combines them.

After the development, the stirring unit 1-1 is separated from the development unit 50, and the substrate 9 to be developed is washed with water and spin-dried to complete the development process.

As the spin chuck provided in the developing unit 50 of the present embodiment, the spin chuck 12 similar to the conventional spin chuck illustrated in FIG. 4 can be suitably used.

<Second embodiment>
FIG. 2 is a cross-sectional explanatory view illustrating a second embodiment of the paddle-type developing device of the present invention.
The second embodiment is characterized in that the stirring unit 1-3 is a stator 2-3-2 of an ultrasonic motor that is in contact with the liquid surface of the liquid developer or is submerged in the liquid. . The developing unit 50 is the same as in the first embodiment.

The stirring unit 1-3 in the second embodiment includes a piezoelectric element 2-3-1 on the disk 13 and a stator 2-3-2 which is a metal plate connected to the piezoelectric element 2-3-1. It is The stator 2-3-2 is vibrated by a signal applied to the piezoelectric element 2-3-1 to form a traveling wave, and has the same function as the stator of the ultrasonic motor.

The traveling wave formed by the stator 2-3-2 may be formed in the direction of rotation along the disk 13, or may be formed linearly. It is sufficient to determine in advance whether the stator 2-3-2 forms a linear traveling wave or a rotating traveling wave.
For example, if the stator 2-3-2 is rectangular and piezoelectric elements are arranged at equal intervals in the longitudinal direction of the rectangle, the stator 2-3-2 is undulated by voltage applied to each piezoelectric element. , and the undulation can form a traveling wave that advances in the longitudinal direction. Similarly, when the stator 2-3-2 is circular, a traveling wave traveling in the circumferential direction can be formed by arranging the piezoelectric elements at equal angular intervals in the circumferential direction.

Also, the disk 13 may be rotatable or may be fixed to the shaft 14 .

After a heaped developer is formed on the substrate 9 to be developed mounted in the developing unit 50, the stator 2-3-2 is brought into contact with the surface of the heaped developer, or immersed in the developer. By forming a traveling wave according to a preset profile in the state of being immersed in the developer, the heaped developer can be driven and agitated according to the traveling wave. The disc 13 may be rotatable or fixed. Since the liquid developer that is heaped up in this manner is agitated, more uniform development can be achieved.

After the development process is completed, the stirring unit 1-3 is separated from the development unit 50, and the development process is completed by washing the substrate 9 to be developed with water and spin-drying it.

<Third Embodiment>
FIG. 3 is a cross-sectional explanatory view illustrating a third embodiment of the paddle type developing device of the present invention.
The third embodiment is characterized in that the stirring unit 1-4 is means for forming a rotating magnetic field parallel to the surface of the substrate to be developed in the heaped developer. The developing unit 50 is the same as in the first embodiment.

Since the developer is conductive, an electromagnetic induction phenomenon occurs when a rotating magnetic field is applied. For example, an increase in magnetic flux produces eddy currents in a direction that hinders the increase in magnetic flux. When an eddy current is generated, this eddy current receives a force according to Fleming's left-hand rule from the magnetic field that formed the magnetic flux. Specifically, when a rotor made of a conductor is placed in a rotating magnetic field formed by a stator of an induction motor, the rotor rotates so as to follow the rotating magnetic field. In this case, the developer corresponds to the rotor.

A third embodiment of the invention uses this principle.
A rotating magnetic field is formed so that the liquid heaped up on the substrate 9 to be developed in the developing unit 50 receives a force so as to rotate within the surface of the substrate 9 to be developed. Specifically, the stator A and the stator B shown in FIG. 3 are arranged at positions spatially forming an angle of 90° in a plane parallel to the surface of the substrate 9 to be developed. Furthermore, by shifting the phases of the currents supplied to the coils of the stator A and the stator B by 90°, a rotating magnetic field rotating in a plane parallel to the surface of the substrate 9 to be developed can be formed. The number of stators need not be limited to two. It is possible to form a rotating magnetic field by arranging three or more coils spatially at equal angular intervals, and causing currents to flow through the coils of each stator with a phase shift that is the same as the spatial angle. can.
The stators A and B are exemplified by electromagnets produced by winding coils around iron cores made of a material with high magnetic permeability.

When the rotating magnetic field is formed in this way, the liquid heaped developer can be rotated in the direction in which the rotating magnetic field rotates. Therefore, it is possible to more effectively agitate the heaped developer, and it is possible to perform more uniform development processing than in the case where such agitation is not performed.

As a specific process, first, a heaped developer is formed on the substrate 9 to be developed mounted on the developing unit 50, and then the heaped developer is agitated by applying a rotating magnetic field. be able to. Uniform development is achieved because the developer that is heaped up in this manner is agitated. By changing the rotational speed of the rotating magnetic field, the magnetic flux density, etc., it is possible to change the state of agitation, so it is possible to set conditions that enable more uniform development.

After the development process is completed, the development process can be completed by washing the substrate 9 to be developed with water and spin-drying it.

The synchronous rotation speed Ns (rpm) of the rotating magnetic field is proportional to the frequency of the power supplied to the stator coil and inversely proportional to the number of stator poles, and can be specifically expressed by the following formula (1). . Here, rpm is an abbreviation for rotation per minute, and represents the number of revolutions per minute.

For example, when two stators A and B are used and the frequency of the power supply is 50 Hz, the synchronous rotation speed Ns of the rotating magnetic field is 3000 (rpm) from Equation (1). If the frequency of the power supply is 1 Hz, it becomes 60 (rpm). If the number of stator stations is doubled to 4 poles, the respective speeds are 1500 (rpm) and 30 (rpm).

The paddle type developing devices 10, 30 and 40 of the present invention have been described in the first to third embodiments. The paddle type developing device of the present invention is not limited to these. For example, in each of the above-described embodiments, the developing device is an example in which the developing unit and the stirring unit are constructed as one system. The present invention is not limited to this, and can also be implemented by adding a stirring unit function as described above to an existing developing device. As a result, even with existing developing devices, it is possible to more effectively agitate the heaped developer, and it is possible to achieve both excellent resolution and suppression of pattern collapse and appearance defects. Become.

In addition to the stirring units 1-1, 1-2, 1-3, and 1-4 described in the first to third embodiments, the stirring units of the paddle type developing device of the present invention include a pendulum type, a An agitating unit consisting of means such as a rotating fan system is conceivable.

In the pendulum-type stirring unit, a plurality of strip-shaped blades in the stirring unit 1-1 are arranged in parallel in the longitudinal direction, and reciprocate with the longitudinal axis as the rotation axis within a certain angular range, thereby moving the substrate on the substrate to be developed. It is means for stirring the developer that has been heaped up in the container. For example, in a spray etching apparatus, a spray nozzle mounting body prepared by mounting a spray nozzle for ejecting an etchant in the longitudinal direction of a liquid supply pipe is rotated and reciprocated within a certain angular range around the liquid supply pipe as a rotation axis. Therefore, it is the same as means for spraying an etchant onto an object to be etched. The reciprocating motion within a certain angular range is similar to the motion of a pendulum, hence the name.

Further, the rotating fan type stirring unit is close to the stirring unit 1-2. The stirring unit 1-2 is simply a method of rotating the disk 13, but the rotating fan system is a case of adopting a fan instead of the disk.

1-1, 1-2, 1-3, 1-4 Stirring unit 2-1 Scan stirring section 2-3-1 Piezoelectric element 2-3-2 Stator 3 . Substrate holding portion 4 . Developing device 11...spin chuck stage 12...spin chuck 13...disk 14...shaft 15...wall surface 16...guide support part 17...guide part 18... ..Spin chuck housing portion 50 ..Development unit

Claims (1)

a spin chuck that rotatably holds the substrate to be developed;
and a paddle-type developing device for agitating the liquid developer in a swelled state , wherein the agitating unit is in contact with or immersed in the liquid surface of the swelled liquid developer. 1. A developing device, comprising: a stator of a motor; the stator has a circular shape in which piezoelectric elements are arranged in a circumferential direction, and forms a traveling wave in the circumferential direction.

Images