JPS638809A - Controlling method for rotation processor - Google Patents

Abstract

PURPOSE:To facilitate synchronizing processors with each other in a simple constitution by sending a synchronizing signal to a sequence control processor from a rotation control processor in accordance with step point data. CONSTITUTION:Schedule data indicating a rotation schedule is preliminarily stored in a memory 19 together with step point data indicating a prescribed progression condition of the rotation schedule as a series of data, and a series of data are read out successively to control rotation of a body to be processed with a motor 3 by a rotation control processor 18. At this time, the synchronizing signal is sent from the rotation control processor 18 to a sequence control processor 9, which controls the processing sequence of a rotation processor, in accordance with step point data, and rotation control is synchronized with the processing squence to control rotation of the body to be processed. Thus, processors are easily synchronized with each other by the simple constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of controlling a rotational processing apparatus that performs predetermined processing while rotating an object to be processed according to a predetermined rotation schedule.

(Prior Art and its Problems) An example of such a rotary processing device is a rotary coating unit included in a spinner device. A spinner device is a device that is generally used together with an exposure machine to perform photolithography processing in the manufacturing process of semiconductor integrated circuits, and is a spinner device that applies a chemical solution such as a photoresist solution to the wafer surface while rotating the semiconductor wafer. It is composed of units.

FIG. 8 is an explanatory diagram showing an example of a spin coating unit,
In the figure, wafer 1 is spun! ? It is suctioned and fixed onto the nail 2 and rotated by a motor 3. Three chemical liquid nozzles 4a are provided above the wafer 1.

4b and 4C are installed, among which nozzles 4a and 4b are fixed obliquely from the outer periphery toward the center, and nozzle 4c is installed so as to be rotatably movable between the outer periphery and the center.

The nozzle 4C is moved by a motor 5, and its position is detected by an encoder 6. Three types of chemical solutions A, B,
C is prepared in advance, and these chemical solutions are applied to the solenoid valves 7a, 7b,
The nozzles 4a, 4b, 4G are supplied through tubes 8a, 8b, 8c, which are selectively connected by the tube 7c.

The pressure of an inert gas (not shown) is constantly applied to the chemical solutions A, B, and C, and when the electromagnetic valve 7 opens, the chemical solutions A, B, and C are discharged from the nozzle 4.

The sequence control processor 9 controls the servo i-structure 11 through the transmission line 10 according to a predetermined rotation schedule.
A rotation reference signal is applied to the servo mechanism 11, and the servo mechanism 11 controls the rotation of the motor 3 so that the rotation of the motor 3, that is, the rotation of the wafer 1, coincides with this rotation reference signal. The sequence control processor 9 also controls the solenoid valve 7a according to the rotation schedule.

7b and 7c, and also controls the rotation of the motor 5 while referring to the signal from the encoder 6 to control the movement of the nozzle 4C.

FIG. 9 is a diagram showing an example of a rotation schedule, in which the horizontal axis represents time and the vertical axis represents the number of rotations. The rotation schedules are N, N2, respectively. A constant speed rotation section T, T4゜T6 that maintains a constant rotation speed of N3, and an acceleration/deceleration rotation section T, T that changes from one constant speed rotation section to another constant speed rotation section.
3. T5. T.

It is composed of a combination of Section T1. At T2, the chemical solution A is discharged, and at section T3. In T4, the nozzle 4C is moved after the chemical liquid B is discharged, and in the sections T, T, and T7, the chemical liquid C is discharged.

FIG. 10 is a block diagram showing an example of the servo mechanism 11 of FIG. 8. The rotational speed of the motor 3 is fed back via the tacho generator 12 and the A/D converter 13, and is compared with a rotational reference signal NR(T) provided from the sequence control processor 9 through the transmission line 10. Then, depending on the deviation, the P control unit 14 and I $1
1 til1 section 15 operates, and the D/A converter 16 and driver section 1 are activated by the sum of Pill I control output and I control output.
Motor 3 is driven via 7, and PI sub-control is performed.

Figure 11 shows the reference rotation speed indicated by the rotation reference signal NIl (T) and the motor 3 when such rotation control is performed.
It is a figure which shows the actual rotation speed of. The solid line indicates the reference rotation speed, and the dotted line indicates the actual rotation speed. Pit, l as shown
According to ll0, the actual rotation speed converges and matches the reference rotation speed in the constant speed rotation section, but since there is a delay in tracking the actual rotation speed with respect to the reference rotation speed in the acceleration/deceleration section, the I component due to this delay The rotation 85 (hatched area in the figure) appears as an overshoot or undershoot when the rotation speed shifts to constant speed. If the acceleration/deceleration period is long, the degree of overshoot or undershoot will increase, and the actual rotation speed will deviate significantly from the reference rotation speed, even if only temporarily.In order to maintain the quality and yield of semiconductor integrated circuits, This has an unfavorable effect on photolithography processes that require precise control.

As a measure to solve such a problem, the present inventor stored a rotation schedule in advance and sequentially read it in the order of sections to control the rotation of the motor, and when the section is a constant speed rotation section, the PI The present invention proposes a motor rotation control method, which is characterized in that P control is initially performed when the acceleration/deceleration rotation section is in progress, and the PI sub control is transferred when acceleration/deceleration is achieved by a predetermined ratio. The application was filed on the same date. When implementing such control, for example, the processing sequence of the spin coating unit is i,
Apart from the sequence control processor II tall,
A processor for controlling the rotation of the motor is provided, and a memory for storing a rotation schedule is provided accompanying this rotation control processor. With this configuration,
The progress of the processing sequence and the progress of the rotation schedule are performed independently under the control of individual processors; in other words, the sequence control processor knows only the processing sequence, and the rotation control processor knows only the rotation schedule. Therefore, new measures are required to establish synchronization between them and to match the processing sequence and rotation schedule.

(Object of the Invention) In view of the above-mentioned viewpoint, the object of the present invention is to provide a rotation processing apparatus that performs a predetermined process while rotating an object to be processed according to a predetermined rotation schedule. An object of the present invention is to provide a control method for a rotary processing device, which can easily establish synchronization between the processors with a simple configuration when the two processors are controlled by separate processors.

(Means for Achieving the Object) In order to achieve the above object, according to the present invention, schedule data representing a rotation schedule is stored in advance as a series of data together with step point data representing a predetermined progress status of the rotation schedule. Then, when controlling the rotation of the object to be processed by a rotation control processor while sequentially reading out the series of data, the rotation control processor controls a processing sequence of the rotation processing device according to the step point data. A synchronization signal is sent to the sequence control processor, and the rotation of the object to be processed is controlled in synchronization with the processing sequence.

(Example) FIG. 1 shows a method for controlling a rotary processing apparatus according to the present invention.
9 is a block diagram showing an embodiment applied to the spin coating unit shown in FIG. 8. FIG. As shown in the figure, in addition to a sequence control processor 9 for controlling the processing sequence of the spin coating unit shown in FIG. A rotation control processor 18 is provided for controlling the rotation. Further, accompanying the rotation control processor 18,
A memory 19 is provided for storing rotation schedules. The sequence control processor 9 and the rotation control processor 18 are connected via a serial line 2o made of, for example, R8-232G. In the sequence control processor 9, a predetermined rotation schedule is specified by the operator from among those prepared in advance, for example, and is saved in the memory 19 via the serial line 20.

The actual rotation speed of the motor 3 is detected by the pulse generator 21 and fed back to the rotation control processor 18. The rotation control processor 18 creates a motor drive signal based on the rotation schedule saved in the memory 19 and the fed-back actual rotation speed, and controls the rotation of the motor 3 via the D/A converter 16 and the driver unit 17. do.

FIG. 2 is a diagram showing an example of a rotation schedule, where the horizontal axis represents time and the vertical axis represents the number of rotations. This rotation schedule is similar to the above-mentioned FIG. 9, with constant speed rotation sections T, T, and T6 maintaining constant rotation speeds of N, N, and N3, respectively, and from one constant speed rotation section to another constant speed rotation section. Moving acceleration/deceleration rotation section T1. T3. T5. It is composed of a combination with T7. Section T1. At T2, chemical solution A is discharged, and at section T3
．． ``At r4, after the chemical liquid B is discharged, the nozzles) It4C move to tl, T5, T6, T7. At r, the g liquid C is discharged.

FIG. 3 is a memory map schematically showing how the rotation schedule is stored in the memory 19. On the memory 19, each rotation section ■, ~T. are identified and saved as rotation schedule stelaph 1 to rotation schedule step n, respectively. For example, the storage area for rotation schedule step k (k-1 to n) is data t.
Storage areas k, nk, SP, and DOK are allocated. Here, data tk is data representing the time required for the rotation schedule step, and data nk is data representing the final rotation number in the rotation schedule step. Data sPk and DOKk are data related to the present invention, and among them, data SPk is step point data indicating whether or not a synchronization message is generated and sent to the sequence control processor 9 at the minimum for a rotation schedule step. Furthermore, even if the time t for a rotation schedule step is timed out, the data DOKk does not contain the final rotation speed nk for the rotation schedule step until a DOK message (processing continuation command signal) is returned from the sequence control processor 9. maintain,
This is flag data indicating not to proceed to the next step. In addition, in the following explanation, DOKk (k=1~n
) means flag data stored in the memory 19, and D
O.K means a processing continuation command signal returned from the sequence control processor 9 in response to DOK,=“1pa.n□ and n. are usually Q rpa+.

FIG. 4 is a memory map showing schedule data for the rotation schedule of FIG.

Step point data SP is data SP2 and S
P4 is "1", indicating that a synchronization message is generated at the end of rotation schedule step 2 and rotation schedule step 4 and sent to the sequence control processor 9.Other step point data SP are "O".
, indicating that synchronous messages are not required. On the other hand, the flag data DOK indicates that DOK4 is "1 pass", and even if the time t4 of the rotation schedule step 4 is timed up, the sequence control processor 9 sends the DOK
This indicates that the final rotation speed n4 of the rotation schedule step 4 is maintained until the message is returned. Other flag data DOKk is "0", indicating that such processing is unnecessary.

FIG. 5 is a flowchart showing the processing procedure of the rotation control processor 18 of FIG. In addition to this Figure 5 below,
With reference to FIGS. 2 and 4, the operation of the rotation control processor 18 will be described, focusing on the synchronization establishment operation between the sequence control processor 9 and the rotation control processor 18. Note that FIG. 6 shows the message sequence on the serial line 20 according to the rotation schedule of FIG. 2, so please refer to this figure as well.

First, in the sequence control processor 9, when the operator specifies a rotation schedule, the rotation schedule data CD is given to the rotation control processor 18 via the serial line 20, and the rotation control processor 18, in step S1, specifies the rotation schedule. Save the data CD in memory 19.

Next, when the setting of the wafer 1 on the spin chuck 2 is completed (see FIG. 8), a rotation start command signal PC8 is sent from the sequence control processor 9 onto the serial line 20, and the rotation control processor 18 performs this command in step S2. Receive rotation start command signal PC8.

After this, the actual motor rotation process starts. First, in step $3, the content of the rotation schedule step number counter is initialized to 1, and the data of rotation schedule step 1 corresponding to this is stored from the memory 19. taken out. At this time, n. =0. In the following step S4, tk of the above-mentioned extracted data
Based on the contents of and n (t, n1 in this case), operation of the motor 3 is started. And in step S5 =
1, that is, rotation schedule step 1. In this case, since it is 1, the process advances to step S6, and a rotation start report signal PSA is sent onto the serial line 20. The sequence control processor 9 receives this rotation start report signal PSA and knows the timing to start discharging the chemical solution A.

Here, an example of the rotation control of the motor 3 based on tk and nk in step S4 will be briefly described with reference to FIG. 7. In FIG. 7, -1, , and +1 are illustrated for three consecutive rotation schedule steps, which are, in order, a constant speed rotation section, an accelerated rotation section, and a constant speed rotation section. First, in the rotation schedule step -1 in the first constant speed rotation section, the rotation of the motor 3 is controlled by the PI sub-control. That is, the motor 3 is controlled to -1 in order to maintain the rotational speed of nk-1 for a time t. Next, in the rotation schedule step of the accelerated rotation section, P control is initially performed, and when acceleration is achieved by a predetermined percentage (90% in Fig. 7), PI control is performed.
Sub-control moves. That is, the rotation of the motor 3 is controlled at an acceleration rate of (nk-nk-1)/tk so that the rotational speed n is reached after time t.
Perform only tIl to eliminate the accumulation of I component due to the delay in tracking the actual rotation speed with respect to the reference rotation speed, and after achieving 90% acceleration, switch to PI control and finally adjust the actual rotation speed to the reference rotation speed. It makes them match. In this case, since the accumulation of the I component (the shaded area in the figure) is very small, the degree of overshoot is also very small. Note that similar control can be performed for the deceleration rotation section to reduce the degree of undershoot.

Returning to FIG. 5, in step S7, it is determined whether step point data SP is specified, that is, whether the content of step point data SP is "1". Since SPl is now 0'', the process proceeds from step S7 to step S10, and the time 1k (in this case 11
) waits for time-up. When the time has expired, the process advances to step S11 to determine whether the flag data DOK is specified, that is, the content of the DOKk data is determined.
It is determined whether it is "1" or not.

Since K1 is "OII," the process proceeds from step 811 to step 813, where it is determined whether this is the final step, that is, whether or not = n.Since K1 is now -1, the process proceeds to step S14. , the contents of the rotation schedule step number counter are incremented by 1, that is, =2, and the data of rotation schedule step 2 is retrieved from the memory 19.

Then, the process returns to step S4, and the rotation of the motor 3 is controlled as described above based on t2 and n2. Since the current value is 2, the process advances from step S5 to step S7, and it is determined whether step point data SP is specified. Since Sr1 is now °1'', it is determined that there is a designation, and the process proceeds to step S8 where the synchronization signal SYN
Wait for the transmission time. This transmission timing may be the same as the time up of time tk (t2 in this case), but
In this embodiment, by transmitting the synchronization signal SYN as early as the transmission time until it actually reaches the sequence control processor 9, the sequence control processor 9 transmits the synchronization signal SYN as early as the transmission time until it actually reaches the sequence control processor 9. This allows the control processor 9 to know the timing. The time Δt for advancing the transmission is preset, for example, through the Silkens 1lill III processor 9. In serial communication, a signal is determined to be meaningful only after all signals are received, so at least that time is required, and Δt is the sum of +α and Δt.

When the time tk-8t has elapsed, the process advances from step S8 to step S9, and a synchronizing signal SYN is sent onto the serial line 20. The sequence control processor 9 receives this II signal SYN, learns the end timing of the rotation schedule step 2, and ends the ejection of the chemical solution A.
Instead, the ejection of chemical solution B is started. When a time period Δt has elapsed after the synchronization signal SYN is transmitted in step S9, it is determined in step S10 that tk time has elapsed, and the process proceeds to step S11, where it is determined whether flag data DOKk is specified. Imari.

Since K2 is "O", the process proceeds to step 813, and since this is not the final step, the process proceeds to step 314, where the content of the rotation schedule step number counter is incremented by 1 and becomes -3, and rotation schedule step 3 is selected. data is retrieved from one memory.

In this rotation schedule step 3, the step point data SP ``O'' and DOK3 = ``O'', so the same processing as in the rotation schedule step 1 described above is repeated. Then, the process proceeds to rotation schedule step 4. In this rotation schedule step 4, 5P4-"1", DOK4-"1"
Therefore, in the flowchart of FIG. 5, the process advances from step S7 to step S8, and when the timing for transmitting the synchronizing signal SYN comes, that is, when the time t4-Δt has elapsed, the process advances to step S9, where the synchronizing signal SYN is transmitted. It is sent out on serial line 20. Upon receiving this synchronization signal SYN, the sequence control processor 9 knows the end timing of the rotation schedule step 4 (actually, since the flag data DOK is specified, the end of the rotation schedule step 4 is extended as described later). , finishes discharging the chemical solution B, and starts moving the nozzle 4C. When the movement of the nozzle 4c is completed, the sequence control processor 9 sends the processing continuation command signal DOK to the rotation control processor 1.
8 and starts discharging the chemical solution C.

On the other hand, on the rotation control processor 18 side, in step 311 in the flowchart of FIG.
If it is determined that "OK" has been specified, the process advances to step S12 and waits for the processing continuation command signal DOK to be returned. Then, a processing continuation command signal DOK is sent from the sequence control processor 9.
is returned, the process goes through step 813 and then goes to step 8.
14, the rotation schedule step number counter is incremented by 1 and becomes 5. This completes the rotation schedule step 4, and data for the next rotation schedule step 5 is retrieved from the memory 19.

After that, the rotation schedule step 5 is performed in the same manner as above.
, 6.7 continues, and when the process of rotation schedule step 7 is completed, it is determined in step S13 that it is the final step, that is, =n (=7 in the present case), and the process proceeds to step S13. Proceed to 815. In step 815, the rotation schedule end report signal PST
is sent onto the serial line 20, and the rotation control processing of the motor 3 by the rotation control processor 18 based on the rotation schedule data shown in FIG. 4 is completed.

Sequence 21J 60 The processor 9 receives the rotation schedule end report signal PST, ends the ejection of the chemical solution C, and ends the series of processing sequences.

In the above description, an embodiment in which the present invention is applied to a rotary coating unit that applies a chemical while rotating a semiconductor wafer has been described in detail. However, the present invention is not limited to this, and the present invention is not limited to this. Therefore, it can be applied to all rotary processing apparatuses that perform predetermined processing while rotating, and in this case, the same effects as in the above embodiment can be achieved.

(Effects of the Invention) As described above, according to the present invention, in a rotation processing apparatus that performs a predetermined process while rotating an object to be processed according to a predetermined rotation schedule, the progress of the processing sequence and the progress of the rotation schedule are controlled. When controlled by separate processors, it is possible to realize a control method for a rotary processing device that can easily establish the same 1n between the processors with a simple configuration.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a diagram showing an example of a rotation schedule, and FIGS.
The figure shows an example of the memory map of the rotation schedule.
FIG. 5 is a flowchart showing the processing procedure according to the present invention, FIG. 6 is a diagram showing the message sequence on the line between the sequence control processor and the rotation control processor, and FIG.
The figure shows improved motor rotation characteristics, Figure 8 shows an example of the configuration of a spin coating unit, Figure 9 shows an example of a rotation schedule, and Figure 10 shows an example of a conventional servo mechanism. The block diagram, FIG. 11, is a diagram showing the rotation characteristics of a conventional motor. 1... Wafer 3... Motor 9... Sequence control processor 18... Rotation control processor 19... Memory

Claims (2)

[Claims] (1) In a rotation processing device that performs a predetermined process while rotating an object to be processed according to a predetermined rotation schedule,
Schedule data representing the rotation schedule,
The step point data is stored in advance as a series of data together with step point data representing a predetermined progress status of the rotation schedule, and when the rotation control processor rotates the object by sequentially reading out the series of data, the step point data is According to the data, a synchronization signal is sent from the rotation control processor to a sequence control processor that controls a processing sequence of the rotation processing device, and the rotation of the object to be processed is controlled in synchronization with the processing sequence. A method of controlling a rotary processing device. (2) The timing of the transmission of step point data from the rotation control processor to the sequence control processor is advanced by the time required for transmission.
A method of controlling a rotational processing device as described in 1.