JP2001345247A - Device and method for applying resist - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resist coater which can efficiently manage the film thickness of a resist applied to a wafer in an in-line state (in the coater) and a method for applying the resist. SOLUTION: In the resist coater, a resist film thickness measuring unit RTM is disposed in addition to a loader/unloader IND1 or IND2, an adhesion improving unit AD, a wafer cooling unit COL1 or COL2, and pre-baking units HP1-HP3. In the measuring unit RTM, wafers coated with resists are automatically led to a film thickness monitor in an in-line state and the monitor measures the film thicknesses of the resists. This resist coater is constituted in such a way that the coater is controlled in accordance with the measured results of the film thicknesses of the resists.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to semiconductor device manufacturing, and more particularly to a resist coating apparatus for forming a resist film on the surface of a semiconductor wafer by spin coating.

[0002]

2. Description of the Related Art A resist coating step is one of the LSI manufacturing steps (wafer steps). Application of a resist is indispensable for using a lithography technique. With the demand for miniaturization and high precision of the pattern formed on the wafer, the requirements of the resist process and its equipment as well as the exposure technology have become more stringent.

FIG. 12 is a block diagram showing a schematic configuration of a conventional resist coating apparatus. The loader / unloader is
Wafers indicated by IND1 or IND2 and accommodated in a carrier (not shown) are transported by the transfer robot into / out of the resist coating step.

[0004] The adhesion improving processing unit AD is provided as a pretreatment for resist coating. Here, HMDS (hexamethyldisilazane) treatment for removing OH groups is performed.
Thereby, the wafer surface is hydrophobized, and the adhesiveness of the resist is improved.

[0005] Wafer cooling unit COL1 or COL
2 is provided with, for example, a cooling plate, and heats the wafer whose temperature has been increased by each predetermined process to a predetermined temperature (normal temperature:
(For example, about 23 ° C.).

The resist coating unit COT performs, for example, a spin coating type resist coating process. That is, after the resist is dropped on the central portion of the fixed wafer, the wafer is rotated at a predetermined number of revolutions, and excess resist is shaken off. Thus, a desired resist film thickness is obtained on the main surface of the wafer.

Each of the pre-bake units HP1 to HP3 is provided with, for example, a hot plate. In order to enhance the adhesion of the resist applied to the main surface of the wafer and adjust the sensitivity, a process of heating the wafer to 80 to 90 ° C. Done.

[0008] Incidentally, the two-story unit area 121 in the figure
Although each unit is shown in two rows for convenience, it is actually a two-story building. The transfer area 1 in the figure
Reference numeral 22 denotes an area including a transfer mechanism such as a transfer robot (not shown).

In the resist coating step, it is necessary to measure and control the thickness of the resist applied on the wafer.
Conventionally, the management of the resist film thickness has been achieved by a film thickness monitor (for example, a bare Si monitor wafer) supplied periodically.

For example, a film thickness monitor prepared for each predetermined lot goes through a normal resist coating process line.
That is, the film thickness monitor is controlled by a transfer robot (not shown) by IND → AD → COL → COT → HP → COL →
Processing is performed in the order of IND.

The film thickness monitor measures the resist film thickness by a resist film thickness measuring device installed separately from the resist coating device. This measurement result is reflected on the wafer rotation speed in the recipe of the resist coating apparatus for film thickness management. A resist film having a desired film thickness is formed by such periodic feedback control.

[0012]

However, the above-mentioned film thickness monitor requires a man-hour to be transported from the resist coating device to the resist film measuring device, thereby increasing the man-hour load. In addition, there is a concern that the work efficiency is reduced because the worker performs the resist film measurement by himself.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a resist coating apparatus and a resist coating method capable of efficiently controlling the thickness of a resist applied on a wafer in-line (in the apparatus). It is.

[0014]

According to the present invention, there is provided a resist coating apparatus comprising: a first unit for loading / unloading a wafer; a second unit for performing a pre-treatment of resist coating on the wafer;
A third unit for performing a resist coating process on the wafer, a fourth unit for increasing the temperature of the wafer, a fifth unit for decreasing the temperature of the raised wafer, a sixth unit for measuring the resist film thickness of the wafer, A wafer transfer mechanism between units.

A resist coating apparatus according to a further preferred embodiment of the present invention includes a first unit for loading / unloading a wafer, a second unit for pre-processing resist coating on the wafer, and a resist coating process for the wafer. Third
A unit, a fourth unit for increasing the wafer temperature,
A fifth unit for lowering the temperature of the raised wafer, a sixth unit for measuring the resist film thickness of the wafer, a seventh unit for loading / unloading a specific wafer separately from the first unit, and And a calculation control mechanism for judging the quality of the resist film thickness measurement result in at least the sixth unit.

According to the resist coating apparatus of the present invention, the sixth unit for measuring the resist film thickness of the wafer is provided in advance. Thereby, the work efficiency can be improved. Further, by providing the arithmetic control mechanism, automation of management of the resist film thickness in accordance with the result of measuring the resist film thickness can be expected.

Further, in the resist coating apparatus of the present invention, the arithmetic control mechanism cooperates with a control mechanism of the third unit to control a resist coating rotation speed of the wafer in accordance with a result of measuring a resist film thickness. It is characterized by the following.

According to the above resist coating apparatus, the number of resist coating revolutions in the third unit which is directly related to resist coating is controlled. The control based on the relationship between the resist film thickness measured by the sixth unit and the resist coating rotation speed in the third unit can cope with a delicate control error of the resist device itself.

Further, in the resist coating apparatus of the present invention, the frequency of execution of the film thickness measurement processing for measuring the resist coating film thickness by at least the sixth unit, the frequency of the control of the resist coating rotation speed by the third unit, and And a storage unit for storing data relating to the result of measurement of the resist film thickness of the semiconductor device, and an output display unit for displaying information corresponding to the data.

According to the resist coating apparatus, the storage unit and the output display unit are advantageous when there are a plurality of resist coating conditions and when a plurality of workers are involved. If necessary, the history of how the resist coating film thickness is controlled can be used as a history, which can be confirmed and applied.

According to the resist coating method of the resist coating apparatus of the present invention, in the resist coating apparatus, a film thickness measuring process for measuring a resist coating film thickness by a specific wafer is performed for each predetermined number of wafer products to be coated with the resist. The result of the measurement of the resist film thickness by the film thickness measurement process is reflected in a predetermined number of wafer products to be coated with the resist.

According to the resist coating method of the resist coating apparatus of the present invention, the resist coating process, that is, the management of the resist film thickness in accordance with the result of the resist film thickness measurement by the film thickness measurement process is performed for the predetermined number of wafer products. You.

Further, a resist coating method of a resist coating apparatus according to a preferred embodiment is characterized in that the resist coating rotation speed of the wafer product is controlled in accordance with the result of the resist film thickness measurement by the film thickness measuring process. I do.

Further, as a resist coating method of a resist coating apparatus according to a preferred embodiment, data on a frequency of a film thickness measuring process for measuring the above-mentioned resist coating film thickness and data on a resist film thickness measurement result are stored, and the data is stored in accordance with the data. In this case, the resist coating process is controlled.

As a preferred embodiment of the resist coating method of the resist coating apparatus, data on the execution frequency of the rotation speed of the resist coating and the measurement result of the resist film thickness corresponding thereto is stored, and the resist is stored in accordance with the data. The coating process is controlled.

The resist coating method of the resist coating apparatus according to the preferred embodiment is characterized in that a processing history based on data necessary for controlling the resist coating process is displayed. A more automated control of the resist film thickness is achieved by the resist coating method of the resist coating apparatus. In addition, it is possible to expect the management of the resist film thickness which is hardly influenced by the experience and maintains the high reliability.

[0027]

FIG. 1 is a block diagram showing a configuration of a resist coating apparatus according to a first embodiment of the present invention.
The loader / unloader is indicated by IND1 or IND2, and is responsible for loading / unloading a wafer contained in a carrier (not shown) into / from the resist coating step by a transfer robot.

The adhesion improving processing unit AD is provided as a pretreatment for resist application. Here, HMDS (hexamethyldisilazane) treatment for removing OH groups is performed.
Thereby, the wafer surface is hydrophobized, and the adhesiveness of the resist is improved.

Wafer cooling unit COL1 or COL
2 is provided with, for example, a cooling plate, and heats the wafer whose temperature has been increased by each predetermined process to a predetermined temperature (normal temperature:
(For example, about 23 ° C.).

The resist coating unit COT performs, for example, a spin coating type resist coating process. That is, after the resist is dropped on the central portion of the fixed wafer, the wafer is rotated at a predetermined number of revolutions, and excess resist is shaken off. Thus, a desired resist film thickness is obtained on the main surface of the wafer.

Each of the pre-bake units HP1 to HP3 is provided with, for example, a hot plate. The pre-bake units HP1 to HP3 perform a process of heating the wafer to 80 ° C. to 90 ° C. in order to strengthen the adhesion of the resist applied to the main surface of the wafer and adjust the sensitivity. Done.

In the embodiment of the present invention, a resist film thickness measuring unit RTM is provided in the apparatus. In the resist film thickness measuring unit RTM, a wafer coated with a resist such as a film thickness monitor is automatically guided in-line, and the resist film thickness is measured. The measurement of the resist film thickness is achieved by interference measurement such as an ellipsometer using a laser beam.

Incidentally, the two-story unit area 11 in the figure is:
Although each unit is shown in two rows for convenience, it is actually two stories. The transfer area 12 in the figure is
The area includes a transfer mechanism such as a transfer robot (not shown).

In this embodiment, the thickness of the resist is controlled by a thickness monitor (for example, a bare Si monitor wafer).
Is supplied to the resist film thickness measurement unit RTM.

For example, a monitor wafer prepared for each predetermined lot goes through a normal resist coating process line. That is, the thickness monitor is a transfer robot (not shown)
IND → AD → COL → COT → HP → CO
Processing is performed in the order of L → RTM → IND.

Alternatively, as a film thickness monitor, only the measurement of the resist film thickness can be performed without going through the usual resist coating process. For example, a thickness monitor on which a resist film has been applied is monitored by a transfer robot (not shown) by IND →
Processing is performed in the order of RTM → IND.

According to the configuration of the above embodiment, the resist film thickness can be automatically measured in-line after the resist is applied to the wafer. For this reason, the man-hour of the worker is reduced,
Work efficiency is greatly improved. Further, it functions as a mere resist film thickness measuring device without a normal resist coating step as a film thickness monitor.

Further, the wafer transfer function of the resist coating apparatus can be shared by the resist film thickness measuring unit RTM.
Therefore, it is more economical to use a resist film thickness measuring device separately from the coating device.

FIG. 2 is a block diagram showing a schematic configuration of a resist coating apparatus according to a second embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals. The difference from the second embodiment is that a loader / unloader MNT for film thickness monitoring for loading / unloading a wafer dedicated for film thickness monitoring is further provided. The other configuration is the same as that of the first embodiment, and the description is omitted.

The loader / unloader MN for monitoring the film thickness
By installing T, the film thickness monitor can be controlled by a transfer robot (not shown) by MNT → AD → COL → COT → H
Processing is performed in the order of P → COL → RTM → MNT.

Alternatively, as a film thickness monitor, only the measurement of the resist film thickness can be performed without going through the usual resist coating process. For example, the thickness of the film on which the resist film is applied is monitored by a transfer robot (not shown) using MNT →
Processing is performed in the order of RTM → MNT.

According to the configuration of the above embodiment, the loader / unloader MNT for monitoring the film thickness is provided. This allows
During the resist coating process on the wafer as a normal product process, a film thickness monitor can be input from the MNT.

For example, the film thickness monitor input from the loader / unloader MNT during normal product processing may be processed preferentially by the interrupt function. Further, the resist coating process on the wafer as a normal product process may be automatically restarted immediately after the film thickness measuring process. However, this does not apply when an abnormality occurs in the film thickness measurement processing using the film thickness monitor.

As described above, the provision of the loader / unloader MNT dedicated to the film thickness monitor and the interrupt function
The resist film thickness can be measured and managed without interrupting the normal product processing. Therefore, the worker only needs to input the film thickness monitor from the loader / unloader MNT regardless of the presence or absence of product processing. This contributes to an improvement in work efficiency.

FIG. 3 is a block diagram showing a schematic configuration of a resist coating apparatus according to a third embodiment of the present invention. The same parts as those in the second embodiment are denoted by the same reference numerals. In the second embodiment, in particular, the arithmetic control mechanism 31 for judging the quality of the resist film thickness measurement result has been described. The arithmetic and control unit 31 includes a loader / unloader IND1 as required.
(Or IND2) and control of the MNT. The other configuration is the same as that of the second embodiment, and the description is omitted.

FIG. 4 is a flow chart showing a resist coating method involving measurement and management of the resist film thickness in the resist coating apparatus of FIG. During a normal product processing of applying a resist to a product wafer, a film thickness monitor automatically interrupts and realizes a resist film thickness measurement and management.

A description will be given with reference to FIGS. The operator sets a plurality of film thickness monitors in the film thickness monitor loader / unloader MNT in advance. The number of normal product processing for resist coating of a product wafer is 1000, for example.
When the number of sheets (for 20 lots) has been reached (processing loop 41), one film thickness monitor is input (processing step 42).

The film thickness monitor includes a resist coating unit C
A resist is applied by OT, and the film thickness T is measured by the film thickness measuring unit RTM (processing steps 43 and 44). That is, the arithmetic control mechanism 31 in FIG. 3 determines whether the measured resist film thickness T is within the standard (processing step 45). If the resist film thickness T is within the standard, the count N of the number of processed products is reset to 0 (processing step 46). Thus, the product processing (the normal wafer resist coating processing) is restarted (processing loop 41).

If it is determined in the processing step 45 that the measured resist film thickness T is out of the standard, for example, an alarm is issued (processing step 47), and the product processing (the resist coating processing of the product wafer) is stopped. . Note that a mechanism for issuing an alarm is not particularly shown in FIG.

According to the resist coating apparatus and the resist coating method according to the third embodiment of the present invention, the operator only needs to set the film thickness monitor on the film thickness monitor loader / unloader MNT, so that the work efficiency is improved. improves.

That is, when the number of processed products reaches the set number, the film thickness is automatically measured. Therefore,
Management omissions do not occur. Whether or not the measured film thickness is within the standard is automatically determined by the apparatus (the arithmetic control mechanism 31 in the apparatus), and therefore, no artificial determination error occurs. When the thickness of the resist film is abnormal, an alarm or the like is issued to stop the product processing.

FIG. 5 is a block diagram showing a schematic configuration of a resist coating apparatus according to a fourth embodiment of the present invention. The same parts as those in the second embodiment are denoted by the same reference numerals. In the configuration of the second embodiment, the arithmetic control mechanism 51 for judging the quality of the measurement result of the resist film thickness is particularly shown. The arithmetic and control unit 51 includes a loader / unloader I as needed.
It is related to the control of ND1 (or IND2) and MNT.

Further, the arithmetic control mechanism 51 controls the resist coating rotation speed of the wafer according to the result of measuring the resist film thickness. That is, it cooperates with the control mechanism of the resist coating unit COT. The other configuration is the same as that of the second embodiment, and the description is omitted.

FIG. 6 is a flow chart showing a resist coating method involving measurement and management of a resist film thickness in the resist coating apparatus of FIG. The function of the film thickness monitor automatically interrupting during the normal product processing of applying a resist to a product wafer is the same as in the third embodiment. Further, in this embodiment, the application rotation speed (the rotation speed of the wafer at the time of resist application) is optimized in order to keep the resist film thickness within the standard.

This will be described with reference to FIGS. The operator sets a plurality of film thickness monitors on the film thickness monitor loader / unloader MNT (processing step 61). One film thickness monitor is loaded (processing step 62). That is, in the film thickness monitor, the resist is applied at a predetermined application rotation speed by the resist application unit COT. Thereafter, the film thickness T is measured by the film thickness measurement unit RTM (processing step 63).

It is determined whether or not the measured resist film thickness T is within the standard (processing step 64). When the resist film thickness T is within the standard, the wafer rotation speed at the time of coating is considered to be optimal, the flow of optimizing the coating rotation speed ends, and the product processing (normal wafer resist coating processing) is restarted. .

However, if it is determined that the measured resist film thickness T is out of the standard, the coating rotation speed is changed (processing step 65), and the film thickness monitor is turned on again.
The input of the film thickness monitor is repeated until the resist film thickness satisfies the standard (processing loop 66).

FIG. 7 is a characteristic diagram showing an example of the relationship between the resist rotation speed and the resist film thickness. Such a relationship is stored in advance in the apparatus as an arithmetic element of the arithmetic control mechanism 51. The processing loop 66 in FIG. 6 may determine the amount of change in the application rotation speed based on, for example, a relational expression obtained by exponential regression from the relation in FIG.

According to the resist coating apparatus and the resist coating method according to the fourth embodiment of the present invention, the operator only needs to set the film thickness monitor to the film thickness monitor loader / unloader MNT, and the resist is automatically set. Optimization of the film thickness is performed.

That is, the arithmetic control mechanism 51 optimizes the coating rotation speed in the resist coating unit COT based on the relationship between the coating rotation speed and the resist film thickness set in advance. Therefore, when the resist is changed or the coating conditions are changed, the time required for optimizing the resist film thickness is reduced. One of the advantages is that the optimization of the resist film thickness can be realized without being affected by the experience of the operator.

Incidentally, in a resist coating apparatus,
Generally, a plurality of application conditions can be set by one device. That is, the specifications of the resist coating film thickness and the frequency of monitoring the film thickness are not the same under all coating conditions, and must be managed. The same applies to the optimization of the application rotation speed. That is, more severe or
When a more gradual control of the resist film thickness is required, the permissible standard ranges differ from one another.

The monitoring result of the resist film thickness, the history of the optimization of the number of coating rotations, etc. are not recorded and managed by the operator, but are stored in the apparatus itself, and if the trend can be viewed as needed. It is convenient.

FIG. 8 is a block diagram showing a schematic configuration of a resist coating apparatus according to a fifth embodiment of the present invention. The same parts as those in the second embodiment are denoted by the same reference numerals. In the configuration of the second embodiment, in particular, the arithmetic and control unit 81 for judging the quality of the resist film thickness measurement result, at least the resist film thickness measurement processing by the resist film thickness measurement unit RTM and the coating rotation speed by the resist coating unit COT A storage unit 82 in which data related to the control of
The output display unit 83 on which information according to this data is displayed is shown. Further, a control input section 84 for setting various values such as application conditions is also shown.

The arithmetic control mechanism 81 controls the resist coating rotation speed of the wafer in accordance with the result of measuring the resist film thickness. That is, it cooperates with the control mechanism of the resist coating unit COT. The storage unit 82 stores at least data on the frequency of execution of the resist film thickness measurement processing by the resist film thickness measurement unit RTM, the frequency of execution of the control of the number of coating revolutions by the resist coating unit COT, and the result of the resist film thickness measurement for these. Is done. That is,
The processing as shown in the flowcharts of FIGS. 4 and 6 is stored as history information. The output display unit 83 provides these pieces of history information to the operator. The other configuration is the same as that of the second embodiment, and the description is omitted.

FIGS. 9 to 11 show the output display unit 83 when the resist coating method involving measurement and management of the resist film thickness is performed in the resist coating apparatus of FIG.
FIG. 9 is a diagram showing a display example of each registered item according to the embodiment.

FIG. 9 shows the frequency and standard for monitoring the resist film thickness registered in the resist coating apparatus for each coating condition.
The table also shows the frequency and standard for optimizing the number of coating revolutions. In the application condition, the condition 2 is different from the condition 3,
Condition 1 controls the resist film thickness more strictly than condition 2. As described above, if the frequency and standard are registered for each resist application condition, the resist coating apparatus automatically performs product processing, resist film thickness measurement, and management work according to the registered contents.

FIG. 10 shows the monitoring result and the history of the resist film thickness under the coating condition 1 shown in FIG. Thus, the result of monitoring the resist film thickness is stored. The operator can display and confirm such a history when necessary.

FIG. 11 shows the result and history of optimizing the resist application rotation speed for the application condition 1 in FIG. In this manner, the history of the optimization of the application rotation speed is also stored. The operator can display and confirm such a history when necessary.

According to the resist coating apparatus and the resist coating method according to the fifth embodiment of the present invention, even if a plurality of resist coating conditions exist, there is almost no need for an operator to intervene on the way. This resist coating apparatus can automatically monitor the resist film thickness and optimize the number of coating rotations according to the registered contents.

The results of monitoring the resist film thickness, and
A history in which the number of coating revolutions is optimized is stored and can be displayed as needed. For this reason, the labor of recording by an operator can be saved. Since the recording operation of the operator is eliminated, it is not necessary to bring the recording paper into a clean room, for example. This contributes to the cleaning of the clean room.

As described above, according to the resist coating apparatus and the resist coating method in each of the embodiments, the number of man-hours required for controlling the thickness of the resist is significantly reduced.
Work efficiency is greatly improved. In addition, it is hardly influenced by the experience of the worker, and can deal with any resist coating conditions in the same manner.

[0072]

As described above, according to the present invention, a resist film thickness measuring unit and a dedicated film thickness monitor loader / unloader are provided in the apparatus. This allows
Efficient control of the resist coating apparatus can be performed according to the result of measuring the resist film thickness. Further, by providing an arithmetic control mechanism, or a storage unit and an output display unit, a resist coating apparatus which is less affected by the experience of an operator and can perform more automated resist film thickness management can be provided. As a result, it is possible to provide a highly reliable resist coating apparatus capable of efficiently managing the resist film thickness applied on the wafer in-line (in the apparatus).

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a resist coating apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a schematic configuration of a resist coating apparatus according to a second embodiment of the present invention.

FIG. 3 is a block diagram illustrating a schematic configuration of a resist coating apparatus according to a third embodiment of the present invention.

FIG. 4 is a flowchart illustrating a resist coating method involving measurement and management of a resist film thickness in the resist coating apparatus of FIG. 3;

FIG. 5 is a block diagram illustrating a schematic configuration of a resist coating apparatus according to a fourth embodiment of the present invention.

FIG. 6 is a flowchart showing a resist coating method involving measurement and management of a resist film thickness in the resist coating apparatus of FIG. 5;

FIG. 7 is a characteristic diagram showing an example of a relationship between a resist coating rotation speed and a resist film thickness.

FIG. 8 is a block diagram illustrating a schematic configuration of a resist coating apparatus according to a fifth embodiment of the present invention.

9 is a first diagram showing a display example of each registered item by an output display unit when a resist coating method involving measurement and management of a resist film thickness is performed in the resist coating apparatus of FIG. 8; .

FIG. 10 is a second diagram showing a display example of each registered item on the output display unit when a resist coating method involving measurement and management of a resist film thickness is performed in the resist coating apparatus of FIG. 8; .

FIG. 11 is a third diagram showing a display example of each registered item on the output display unit when a resist coating method involving measurement and management of a resist film thickness is performed in the resist coating apparatus of FIG. 8; .

FIG. 12 is a block diagram showing a schematic configuration of a conventional resist coating apparatus.

[Explanation of symbols]

 IND1, IND2: loader / unloader AD: adhesion improvement processing unit COL1, COL2: wafer cooling unit COT: resist coating unit HP1 to HP3: prebake unit RTM: resist film thickness measuring unit MNT: film thickness monitor loader / unloader 11, 121: two-story unit area 12, 122: transport area 41, 66 ... processing loop 42-47, 61-65 ... processing step 31, 51, 81 ... arithmetic control mechanism 82 ... storage unit 83 ... output display unit 84 ... control Input section

Claims (10)

[Claims] 1. A first unit for loading / unloading a wafer, a second unit for pre-processing resist coating on a wafer, a third unit for coating resist on a wafer, and increasing a wafer temperature. A resist comprising: a fourth unit; a fifth unit for lowering the temperature of the raised wafer; a sixth unit for measuring the resist film thickness of the wafer; and a wafer transfer mechanism between the units. Coating device. 2. The resist coating apparatus according to claim 1, further comprising a seventh unit for loading / unloading a specific wafer separately from said first unit. 3. A first unit for loading / unloading a wafer, a second unit for pre-processing resist coating on the wafer, a third unit for coating resist on the wafer, and increasing the wafer temperature. A fourth unit, a fifth unit for lowering the temperature of the raised wafer, a sixth unit for measuring the resist film thickness of the wafer, and a seventh unit for loading / unloading a specific wafer separately from the first unit. A resist coating apparatus, comprising: a wafer transfer mechanism between the respective units; and an arithmetic control mechanism for determining at least the quality of the resist film thickness measurement result in the sixth unit. 4. The control unit according to claim 3, wherein said arithmetic and control unit cooperates with a control unit of said third unit to control a resist coating rotation speed of said wafer in accordance with a result of resist film thickness measurement. The resist coating apparatus according to the above. 5. A frequency of execution of a film thickness measurement process for measuring a resist coating film thickness by at least the sixth unit, a frequency of control of a resist coating rotation speed by the third unit, and data relating to a resist film thickness measurement result with respect thereto. The resist coating apparatus according to claim 3, further comprising: a storage unit that stores information, and an output display unit that displays information corresponding to the data. 6. In a resist coating apparatus, a film thickness measurement process for measuring a resist coating film thickness by a specific wafer is performed for each predetermined number of wafer products to be coated with a resist, and the resist film thickness by the film thickness measurement process is measured. A resist coating method for a resist coating apparatus, wherein a measurement result is reflected in a predetermined number of wafer products to be coated with the resist. 7. A resist coating method for a resist coating apparatus according to claim 6, wherein a resist coating rotation speed of said wafer product is controlled in accordance with a result of measuring a resist film thickness by said film thickness measuring process. 8. The method according to claim 1, wherein data relating to the frequency of the film thickness measuring process for measuring the resist coating film thickness and the result of measuring the resist film thickness are stored, and the resist coating process is controlled according to the data. Item 7. A resist coating method for the resist coating device according to Item 6. 9. The method according to claim 7, wherein data relating to the frequency of execution of the control of the number of rotations of the resist coating and the result of measurement of the resist film thickness corresponding thereto are stored, and the resist coating process is controlled according to the data. The resist coating method of the resist coating apparatus according to the above. 10. A resist coating method for a resist coating apparatus according to claim 8, wherein a processing history based on said data necessary for controlling said resist coating processing is displayed.