JP2844210B2 - Rotation processing method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a rotation processing technique, in particular, a processing liquid is supplied to an object to be processed, and the object to be processed is rotated so that a predetermined processing is performed by the processing liquid. The present invention relates to a technology for detecting an end point of a process in a rotation processing apparatus to be implemented, for example, to a technique that is effectively used as a wafer developing device in a semiconductor device manufacturing process.

[Conventional technology]

Published in January 1988, "SEMI Magazine" as a developing device that performs wafer development processing in the manufacturing process of semiconductor devices.
As described in “CON NEWS” on pages 76 to 81, an apparatus having an end point detection device has been proposed. That is,
This end point detection device irradiates the developing wafer with measurement light,
Measure the reflected light intensity during development, detect the end point of the development processing by the measured change in intensity and the preset arithmetic expression and coefficient, and let the development device terminate the development processing. It is configured.

[Problems to be solved by the invention]

However, in such an end point detection device, no consideration is given to the fact that the development speed differs depending on the pattern under the hot resist (hereinafter referred to as “resist”). As a reference, the inventors have determined that the development end point of the entire wafer is determined, and as a result, there is a problem that the variation in the development speed in the wafer becomes an error in the end point determination. .

For example, when the underlying pattern in the same wafer has a rough portion and a dense portion, it is known that the resist film thickness changes depending on the step of the underlying pattern and the degree of the denseness. Has a pattern dependency. In such a case, when the end point detection device is used, the sampling signal is different between the case where the sampling is performed for the coarse pattern and the case where the sampling is performed for the dense portion, and as a result, one end point is obtained. Not determined.

SUMMARY OF THE INVENTION An object of the present invention is to provide a rotation processing technique capable of preventing an error in end point detection from occurring due to a variation in processing speed depending on a regional situation difference such as a pattern density of an underlayer in a wafer. To provide.

The above and other objects and novel features of the present invention are as follows.
It will be apparent from the description of this specification and the accompanying drawings.

[Means for solving the problem]

The outline of a representative invention among the inventions disclosed in the present application will be described as follows.

That is, a spin head that holds and rotates the object to be processed, a supply pipe that supplies a processing solution onto the object to be processed held by the spin head, and a measuring light that irradiates the object to be processed and reflects the reflected light. A rotary processing device that receives light and detects an end point of the processing by the processing liquid based on the received light output, wherein the end point detection device detects a predetermined location on the object to be processed, Irradiating the detected light with the measurement light in synchronization with the rotation of the spin head, receiving reflected light from this position, and detecting the end point of this position by its light receiving output, and The measurement device is configured to adjust a measurement area of the object to be scaled up or down.

[Action]

According to the above-described means, the sampling of the end point detection is performed at the same place in the object to be processed between each of the objects to be processed each time each of the objects is processed. Even if there is a regional difference (variation), the end point detection with no difference is always constantly performed between the respective workpieces.
Therefore, by previously obtaining the relationship between the processing status and the processing speed for the certain place, it is possible to always perform a fixed end point detection every time processing is performed on each of the same type of workpiece. As a result, the quality and reliability of each of the processing operations on the workpiece can be improved.

In addition, when the end point is detected, the measurement area on the workpiece is scaled and adjusted, so that the optimal measurement area can be adjusted according to the difference in the setting conditions such as the model of the workpiece and processing conditions. Since the selection can be made, the accuracy and reliability of the end point detection and processing can be further improved.

〔Example〕

FIG. 1 is a schematic front sectional view showing a wafer developing apparatus according to one embodiment of the present invention, FIG. 2 is a schematic front sectional view showing an orientation flat detecting operation, and FIG. 3 is a III-III in FIG. FIG. 4 is a block diagram showing the end point detecting device, and FIGS. 5 and 6 are explanatory diagrams for explaining the operation thereof.

In the present embodiment, the rotary processing apparatus according to the present invention is configured as a wafer developing apparatus that performs a rotary developing process on the resist 1b that has been coated on the wafer 1 and has been exposed.
The wafer developing apparatus includes a processing container 2 formed in a substantially bowl shape having an open upper surface. An air supply port 3 is provided on an upper surface of the container 2, and a plurality of air supply ports 3 are provided on a bottom wall of the container 2. The exhaust ports 4 are respectively opened. An elevator 5 composed of a cylinder device or the like is installed concentrically and vertically upward just below the processing vessel 2, and a table 7 is horizontally arranged at the upper end of a stroke shaft 6 so as to be lifted and lowered. It is supported by. On the table 7 is a motor 8
Are arranged concentrically with the processing container 2 and installed vertically upward, and the rotating shaft 9 of the motor 8 is inserted into the processing container 2 through the bottom wall of the processing container 2. Rotating shaft 9
A spin head 10 is horizontally supported at the upper end of the insert so as to be rotated, and the spin head 10 holds a wafer 1 as an object to be processed by vacuum suction means (not shown). It is configured to rotate integrally.

On the other hand, just above the processing container 2, a developing solution
A feed pipe 12 for feeding the feed pipe 11 is provided concentrically with the processing vessel 2 and is provided vertically downward, and the feed pipe 12 is moved up and down and horizontally moved by a suitable driving means (not shown). It is supposed to be. The liquid supply unit 13 is connected to the liquid supply pipe 12.
The liquid supply unit 13 is configured to supply a predetermined amount of the developer 11 at a predetermined time.

A washing nozzle 14 is provided directly above the processing container 2 with a developer 11.
The flush nozzle is equipped so that the
14 is also adapted to be raised and lowered and moved horizontally by suitable driving means (not shown). A washing liquid supply unit 15 is connected to the washing nozzle 14, and the washing liquid supply unit 15 is configured to be able to supply a predetermined amount of a cleaning liquid such as pure water at a predetermined time.

A wafer 1 as an object to be processed is loaded directly above the processing container 2 by a loading device (not shown), and the processed wafer 1 is loaded by an unloading device (not shown). It is designed to be carried out.

A centering device 16 is provided above the processing chamber 2, and the centering device 16 is configured to center the wafer 1 supplied by the loading device with respect to the spin head 10. That is, the centering device 16 includes a pair of cylinder devices 17, 17, and the two cylinder devices 17, 17 are opposed to each other with the extension line of the rotation center axis of the spin head 10 above the processing container 2. And are installed horizontally inward. A template 19 is horizontally disposed at the tip of the pi-spin rod 18 of the cylinder device 17 and supported so as to be integrally moved.
Of the wafer 1 is formed in an arcuate shape extending around the circumference of the wafer 1.

An end point detection device 20 is incorporated in the wafer developing device. The end point detection device 20 detects an orientation flat (hereinafter, referred to as an orientation flat) 1a as a characteristic portion of the wafer 1, and an end point detection device. A measuring device for measuring and a moving device for moving the measuring device to a predetermined measuring position are provided.

The orientation flat detector 21 includes an XY table 22 and an XY table 22.
The table 22 is installed horizontally on one side of the processing container 2. A motor 23 is mounted on the XY table 22 so as to be arranged vertically upward and moved in the XY direction, and an arm 25 is horizontally arranged on a rotating shaft 24 of the motor 23 and is integrally rotated. Is fixedly supported at one end. At the free end of the arm 25, a light emitter 26 and a light receiver 27 are arranged and fixed so as to face each other on a vertical line, and the light receiver 27 can receive light emitted from the light emitter 26. ing.

A measurement position calculator 28 is connected to an output terminal of the light receiver 27, and a setting unit 29 is connected to another input terminal of the calculator 28. The calculation unit 28 detects the position of the orientation flat 1a based on the output of the light receiver 27,
The position to be measured in the wafer 1 is calculated based on the command signal from the controller 29. The calculation result by the calculation device 28 is transmitted to a controller of a mobile device described later.

The moving device 31 includes an XY table 32. The XY table 32 is provided horizontally on one side of the processing container 2 on the side opposite to the orientation flat detector 21. A motor 33 is mounted on the XY table 32 so as to be arranged vertically upward and moved in the XY direction, and an arm 35 is horizontally arranged on a rotation shaft 34 of the motor 33 and is integrally rotated. Is fixedly supported at one end. A measuring device described later is supported on the free end of the arm 35 so as to be integrally moved. The XY table 32 and the motor 33 of the moving device 31 are configured to be controlled by a controller 36.The controller 36 controls the XY table 32 and the motor 33 in accordance with a command from the measurement position calculation device 28, and controls the measurement device. It is configured to be moved to a predetermined position.

The measuring device 40 includes a main body 41 formed in a lens barrel shape, and the main body 41 is supported by a free end of the arm 35 of the moving device 31. The main body 41 is provided with a light emitter 42 and a light receiver 43. The light projector 42 is configured to irradiate the wafer 1 held by the spin head 10 with measurement light, and the light receiver 43 is configured to receive the measurement light reflected by the wafer 1.

In addition, a lens 44 is provided on the main body 41 with a light emitter 42 and a light receiver 43.
This lens 44 is configured so that the measurement area can be scaled and adjusted by a measurement area scaling device 45 attached to the main body 41. A determination device 46 is connected to an output terminal of the light receiver 43, and a setting unit 47 is connected to another input terminal of the determination device 46. Further, a synchronization device 49 is connected to another input terminal of the determination device 46, and the synchronization device 49 is an encoder attached to the motor 8.
A synchronization signal is transmitted to the determination device 46 based on the detection signal from 48. The judging device 46 is configured to execute the detection of the end point of the development at the same position in the wafer 1 to be rotated in synchronization with the rotation of the wafer 1 by an operation described later.

Next, a description will be given of a case where the rotation processing method according to an embodiment of the present invention is applied to the development processing method by forming the operation of the developing device having the above-described configuration.

When the resist 1b is applied and the exposed wafer 1 is loaded directly above the processing container 2 by the loading device, the table 7 is raised by the elevator 5, and the spin head 10 is raised, and the wafer 1 is transferred onto the spin head 10.

Subsequently, the pair of front and rear cylinder devices 17, 17 in the centering device 16 are operated, and the respective piston rods 18, 18
The position of the wafer 1 is regulated by contacting the template 19, 19 supported on the tip of the wafer 1 with the circumferential surface of the wafer 1 from both sides symmetrically. Since the position regulation from both sides of the template 19 is performed symmetrically with respect to the center line of the spin head 10, the wafer 1 is centered on the center line of the spin head 10. In this state, the wafer 1 is vacuum-adsorbed and held by the spin head 10.

Then, the XY table 22 and the motor 23 in the orientation flat detector 21 are operated, and the rotation of the arm 25 causes the light emitter 26 and the light receiver 27 provided at the distal end thereof to approach one side of the wafer 1. Subsequently, the wafer 1 held by the spin head 10 is gently rotated by the motor 8, and the light projector 26 projects the wafer 1. With the rotation of the wafer 1, the light projected on the wafer 1 passes through the portion of the orientation flat 1a when the orientation flat 1a passes therethrough.
The light is received by the light receiver 27. Therefore, the orientation flat 1a on the wafer 1 currently held by the spin head 10
Is detected by the output of the light receiver 27.

Then, the detection output of the light receiver 27 is transmitted to the measurement position calculator 28. This calculation unit 28 is based on the output of the light receiver 27,
At present, the position of the orientation flat 1a on the wafer 1 held by the spin head 10 is detected.

On the other hand, the position on the wafer 1 where the measurement by the measuring device 21 is to be performed is input from the setting unit 29 to the arithmetic unit 28. That is, the setting unit 29 indicates the measurement execution position by the coordinate position of the wafer 1 with respect to the orientation flat 1a. The arithmetic unit 28 determines the current position of the spin head based on the detected current position of the orientation flat 1a and the position indicated by the setting unit 29.
The measurement execution position on the wafer 1 held by 10 is obtained, and the coordinate position is transmitted to the controller 36 of the moving device 31.

The controller 36 controls the XY table 32 and the motor 33 based on this transmission, thereby moving the measuring device 40 supported by the tip of the arm 35 to the designated coordinate position. As a result, the measurement device 40 is currently held by the spin head 10 and faces the measurement execution device in the wafer 1 on which measurement is to be performed. In the present embodiment, the movement of the measuring device 40 is performed after the wafer 1 has been lowered into the processing chamber 2, but may be configured to be performed before the wafer 1 is lowered.

When the developing operation is started, the wafer 1 held by the spin head 10 is lowered into the processing container 2 by the operation of the elevator 5.

The developing solution 11 is supplied to the upper surface of the wafer 1 held by the spin head 10 by the liquid supply pipe 12 while being rotated by the motor 8. The developer 11 supplied onto the wafer 1 is evenly diffused and applied to the entire surface of the wafer 1 by the rotation of the wafer 1 and the surface tension of the liquid. At this time,
When the liquid supply pipe 12 is moved horizontally, the developer 11 is more uniformly applied on the wafer 1. When the developer 11 is applied to the entire upper surface of the wafer 1, the rotation of the motor 8 is stopped.

On the other hand, when the developing solution 11 is supplied onto the wafer 1, the end point detecting operation by the measuring device 40 is started. That is, the measuring light of the non-exposure type monochromatic light wavelength is applied to the developing wafer 1 by the light projector 42, and the reflected light from the wafer 1 is received by the light receiver 43. The reflectance of the measurement light reflected by the wafer 1 and sampled by the light receiver 43 is:
Depending on the change in the thickness of the resist 1b as the development proceeds, the fifth
Draw a sinusoidal curve as shown.

Thus, the variation in reflected light intensity is seen
As shown in FIGS. 6 (a), (b) and (c),
This is because thin-film interference occurs between the reflected light from the uppermost end surface of the resist 1b and the reflected light from the base surface of the wafer 1. The end of the interference fringes shown in FIG. 6 (c) and the portion where the reflectance level is almost constant are the end points of the loss of the film thickness, and are the true end points.

Initially, development proceeds rapidly in the vertical direction, as shown in FIG. 6 (b). This is the reason why the reflected light intensity shows a sinusoidal change. As development progresses,
As shown in FIG. 6 (c), it is time to remove the resist from the substrate for the first time.
The end time corresponds to 1/2 fringe earlier, because the end time can be identified much more accurately than the breakthrough. When the resist 1b is removed, the exposed line edge largely moves laterally while the development is continued. Therefore, during the development, the interference film characteristics due to the initial resist 1b cannot be seen. The width of the interference fringes is determined by the percentage of the exposed wafer and the average minimum line width.

Such an end point detection operation by the measuring device 40 is performed by the operation described above, and the measuring device 40
Therefore, the process is always performed on a predetermined position of the wafer 1. In addition, since the end point detection operation by the measuring device 40 is executed in synchronization with the rotation of the wafer 1 by the synchronization device 49, the end point detection operation is executed at a predetermined position on the wafer 1 even during the rotation of the wafer 1. .

That is, the rotation of the wafer 1 is detected by the encoder 48 that detects the rotation of the motor 8. This encoder 48
Is transmitted to the synchronization device 49, a synchronization signal is created by the synchronization device 49, and the synchronization signal is transmitted to the projector 42 of the measurement device 40. When the projector 42 emits light in synchronization with this synchronization signal,
Since the light receiver 43 receives light in synchronization with the rotation of the wafer 1, the end point detection operation is executed in synchronization with the rotation of the wafer 1. For example, when the light emitter 42 is set to emit light once for each rotation of the wafer 1, the end point detection operation by the light receiver 43 is always performed at a fixed place even while the wafer 1 is rotating. Will be.

When the area of the end point detection operation with respect to a certain place on the wafer 1 is enlarged or reduced, for example, the position of the lens 44 is changed by the enlargement / reduction device 45 so that the diameter of the illumination spot of the light projector 42 is reduced. Scaled up or down. That is, as the illumination area of the light projector 43 is enlarged or reduced, the measurement area of the light receiver 42 is also enlarged or reduced.

In this way, if the end point detection is always performed for a certain location of the wafer 1 every time the developing operation for each wafer 1 is performed, there is a difference in the density of the pattern under the resist 1 b in the wafer 1. , The end point detection is performed without any difference between the wafers 1, 1,.... Therefore, by obtaining the relationship between the development progress degree and the output state of the light receiving device 43 for the certain place on the wafer 1, the same kind of wafers 1 and 1 are always kept constant each time each development processing is performed. Can be performed. As a result, the quality and reliability of the development processing for each of the same kind of wafers 1 can be improved.

The relationship between the current increase degree of the certain place on the wafer 1 and the output state of the light receiver 43 is obtained in advance by an empirical rule based on experiments, past results, and the like.
It is set to 47. The output status from this setting unit 47,
The actual output status from the light receiver 43 is compared with the actual output status in the determination device 46, and the end point detection at a certain location on the wafer 1 is properly executed.

When the end point of the development is determined by the determination device 46,
As the motor 8 starts rotating, pure water from the cleaning liquid supply unit 15 is supplied to the wafer 1 from the washing nozzle 14. As a result, the developing solution 11 on the wafer 1 is washed away with pure water and centrifuged, so that the development is stopped and the development is fixed. At this time, the washing nozzle
When the 14 is moved horizontally, the cleaning is performed more effectively.

When the development is fixed, after appropriate centrifugal dehydration, the wafer 1 is raised from the inside of the processing container 2 to the position of the unloading device by the elevator 5, lowered by the unloading device from the spin head 10, and carried out to the next step. Go.

Thereafter, by repeating the above operation, the developing operation is sequentially performed on each wafer 1 one by one. Then, each time the development processing of each wafer 1 is performed, the end point detection using the same location in the wafer 1 is performed.
1 ... End point detection between each other is executed so as to maintain the same identity. Therefore, each wafer 1, 1
... Because there is no variation in the development processing between the processings, constant quality and reliability are ensured, and the quality and reliability of products obtained through this processing are improved.

 According to the above embodiment, the following effects can be obtained.

(1) By performing sampling of the end point detection for the same place in the processing object between the processing objects each time the processing is performed, a regional difference (variation) in the progress of the processing in the processing object is obtained. Even if there is, since the end point detection with no difference is always performed constantly between each of the objects to be processed, it is possible to maintain constant quality and reliability between each of the processes, As a result, the quality and reliability of the product obtained through the processing can be improved.

(2) By configuring the end point detection device of the rotary processing device for the wafer to detect the orientation flat as a feature in the wafer, the orientation flat and the XY in the wafer are detected.
Since the fixed point can be easily obtained based on the relationship with the coordinates, the structure of the end point detecting device can be simplified, and the workability of the fixed point measurement detection can be improved.

(3) In the end point detection device of the rotation processing device for the wafer, by synchronizing the measurement of the measurement device with the rotation of the wafer, the measurement can be continued at a fixed point in the wafer even during the rotation of the wafer. Accuracy and reliability can be improved.

(4) By configuring so that the measurement area of the measurement device in the end point detection device can be enlarged or reduced and adjusted, an optimal measurement area can be set in response to a difference in setting conditions such as a product model and processing conditions. Since the selection can be made, the accuracy and reliability of the end point detection and processing can be further improved.

Although the invention made by the inventor has been specifically described based on the embodiments, the present invention is not limited to the embodiments, and it is needless to say that various changes can be made without departing from the gist of the invention. Nor.

For example, an apparatus for detecting a characteristic portion of a wafer is not limited to detecting the orientation flat of the wafer, but may be configured to detect another characteristic portion such as a characteristic pattern formed on the wafer. You may.

The measurement light is not limited to the light of the non-exposure type monochromatic light wavelength, but may be a polarized light or the like.

The specific structures of the orientation flat detector, the moving device, the measuring device, and the developing device are not limited to the configurations disclosed in the above embodiments.

In the above description, the case where the invention made by the present inventor is mainly applied to the developing technique which is the background of the application has been described. However, the present invention is not limited to this, and the resist is coated on the wafer by rotation. To a general rotation processing apparatus such as a spinner coating apparatus and a general rotation processing method using such a rotation processing apparatus. For example, in the case of a spinner coating apparatus, end point detection is performed on the thickness of a coating film formed on a wafer by rotation.

Also, the case of processing on a wafer has been described. However, the present invention is not limited to this, and is generally applied to a processing target such as a photomask or a printed wiring board, which is subjected to processing such as development or coating by rotation. Can be applied to

〔The invention's effect〕

The effect obtained by the representative one of the inventions disclosed in the present application will be briefly described as follows.

By performing sampling of the end point detection for the same place in the processing object between the processing objects each time, there is a regional difference (variation) in the progress of the processing in the processing object. Even in this case, since the end point detection with no difference is always performed constantly between the respective objects to be processed, it is possible to maintain a constant quality and reliability between the respective processes, and as a result, The quality and reliability of the product obtained through the processing can be improved.

In addition, when the end point is detected, the measurement area on the workpiece is scaled and adjusted, so that the optimal measurement area can be determined in response to the difference in the setting conditions such as the model of the workpiece and processing conditions. Since the selection can be made, the accuracy and reliability of the end point detection and processing can be further improved.

[Brief description of the drawings]

FIG. 1 is a schematic front sectional view showing a wafer developing apparatus according to one embodiment of the present invention, FIG. 2 is a schematic front sectional view showing an orientation flat detecting operation, and FIG. 3 is a III-III in FIG. FIG. 4 is a block diagram showing an end point detecting device, and FIGS. 5 and 6 are explanatory views for explaining the operation thereof. DESCRIPTION OF SYMBOLS 1 ... Wafer (workpiece), 2 ... Processing container, 3 ... Air supply port, 4 ... Exhaust port, 5 ... Elevator, 6 ... Stroke axis, 7 ... Table, 8 ... Motor, 9 ... rotating shaft, 10 ... spin head, 11 ... developer, 12 ... liquid supply pipe, 13 ... liquid supply unit, 14 ... washing nozzle, 15 ... cleaning liquid supply unit, 16 ... alignment Device, 17… Cylinder device, 18… Piston rod, 19… Mold plate, 20… End point detection device, 21… Ori-flat detection device, 22 XY table, 23… Motor, 24… Rotating shaft , 25 ... arm, 26 ...
... Emitter, 27 ... Receiver, 28 ... Measurement position calculator, 29 ...
… Setting unit, 31… Moving device, 32… XY table, 33…
Motor, 34: Rotating shaft, 35: Arm, 36: Controller, 40: Measuring device, 41: Main body, 42: Emitter, 43
…… Receiver, 44 …… Lens, 45 …… Enlargement / reduction device, 46…
... Judgment device, 47 ... Setting unit, 48 ... Encoder, 49 ...
Synchronization device.

Claims (4)

(57) [Claims] 1. A rotation processing method in which a processing liquid is supplied and diffused onto a processing object while the processing object is being rotated, and an end point of processing by the processing liquid is detected. A predetermined measurement execution location on the workpiece is determined based on the location of the specific shape whose shape is recognized and recognized, and the measurement light is emitted to the determined measurement execution location in synchronization with the rotation of the workpiece. While being irradiated, the reflected light from the measurement execution place is received, the end point is detected based on the received light output, and when the end point is detected, the measurement area on the workpiece is changed in scale. A rotation processing method. 2. The method according to claim 1, wherein when detecting an end point based on the received light output, a temporal change in the received light intensity is compared with a temporal change in the reflected light intensity determined in advance, and a current value of the received light intensity is compared with the temporal change in the reflected light intensity determined in advance. 2. The rotation processing method according to claim 1, wherein an end point is determined when a change substantially coincides with a preset value. 3. A spin head for holding and rotating an object to be processed, a liquid supply pipe for supplying a processing liquid onto the object to be processed held by the spin head, and irradiating the object to be measured with measurement light; An end point detection device that receives the reflected light and detects an end point of the processing with the processing liquid based on the received light output, wherein the end point detection device locates a predetermined place in the workpiece. Detecting, irradiating the detected light with the measurement light in synchronization with the rotation of the spin head, receiving reflected light from this position, and detecting the end point of the position by the light reception output. A rotation processing device, wherein the measurement device is configured to adjust a scaling of a measurement area on the workpiece. 4. An apparatus according to claim 1, wherein said end point detection device irradiates said measurement light to a predetermined portion determined based on said detected characteristic portion, and a characteristic portion detection device for detecting a characteristic portion of said workpiece. 4. The rotating device according to claim 3, further comprising a measuring device for receiving the reflected light from the place, and a synchronizing device for synchronizing the measurement of the measuring device with the rotation of the spin head. Processing equipment.