WO2006049037A1

WO2006049037A1 - Exposure condition correcting method, substrate processing equipment and computer program

Info

Publication number: WO2006049037A1
Application number: PCT/JP2005/019563
Authority: WO
Inventors: Kazuo Sawai; Akihiro Sonoda
Original assignee: Tokyo Electron Limited
Priority date: 2004-11-01
Filing date: 2005-10-25
Publication date: 2006-05-11
Also published as: JP2006128572A

Abstract

A resist film is formed on a wafer (W) by using a resist coating/development process system (1), which performs resist film formation and development process to the wafer (W), and exposure equipment (14) which performs exposure process. A plurality of portions of the resist film are sequentially exposed with the same pattern by changing focus values and are developed. The resist coating/development process system (1) measures the line width of an obtained resist pattern by scatterometry technology, decides an optimum focus value from a relationship between the obtained line width and a focus value corresponding to the width, and transmits data for correcting the focus value of the exposure equipment (14) to the exposure equipment (14) by data communication without manual operation. The exposure equipment (14) corrects the focus value based on the data.

Description

Specification

Exposure condition correction method, substrate processing apparatus, and computer program

The present invention relates to an exposure condition correction method capable of optimally setting an exposure condition when exposing a resist film formed on a semiconductor wafer or a flat panel display (FPD) substrate, and the exposure condition correction method The present invention relates to a substrate processing apparatus for carrying out the above and a computer program for executing the exposure condition correction method.

Background art

[0002] For example, in a photolithography process in a semiconductor device manufacturing process, a resist solution is applied to the wafer surface to form a resist film, and the resist film is exposed to a predetermined pattern and developed. Thus, a pattern is formed on the resist film.

In order to confirm whether the formed resist pattern has a desired line width and shape during the photolithography process, the resist pattern line width and LER (Line Edge Roughness) are regularly checked. Is measured. If the resist pattern deviates from the desired line width and shape, the exposure conditions are corrected.

[0004] SEM is generally used for measuring the line width and the like of such a resist pattern. However, although SEM observation has the advantage that the resist pattern can be viewed directly, it takes a long time for measurement, experience is required for device operation and shape observation, and observer's subjectivity is easy to enter. There are disadvantages such as difficulty in maintaining the reliability of line width due to LER. Therefore, in recent years, instead of SEM, a method using a skitterometry technique has come to be used! /

[0005] Sky telometry technology is to calculate the diffracted light intensity distribution for an arbitrary pattern shape, for example, to create a library in advance and to enter the light into the measurement target, and to measure the diffracted light intensity. An angular direction distribution is detected, and the width, height, etc. of the pattern to be measured are estimated by pattern matching between the detection result and the above-mentioned library.

[0006] On the other hand, there are currently different manufacturers of resist coating and developing devices and exposure devices. Are controlled separately, the correction of exposure conditions has conventionally been done by preparing an exposed resist pattern by changing the exposure amount and focus value with a predetermined test pattern, and measuring its shape by SEM. This is done by observing the appropriate exposure conditions and inputting the appropriate exposure conditions to the exposure equipment by the equipment operator.

[0007] However, in such a method, human error such as an error in shape measurement by SEM observation, an input error such as reverse input of the positive / negative sign, misplacement of decimal point, etc. when data is input manually. A mistake occurs and wasteful processing that does not result in a product is performed, and the quality of the product deteriorates.

[0008] Patent Document 1 describes that it is possible to control the exposure time and the exposure amount based on the measurement results obtained by the above-described sky telometry. There is no specific method for correcting this.

Patent Document 1: JP 2002-260994 A

Disclosure of the invention

[0009] An object of the present invention is to provide an exposure condition correction method capable of setting an optimal exposure condition in an exposure apparatus from a resist pattern shape measurement result without causing an artificial mistake. .

Another object of the present invention is to provide a substrate processing apparatus and a computer program for executing this exposure condition correction method.

[0011] According to a first aspect of the present invention, a resist film is formed on a substrate, a plurality of portions of the resist film are sequentially exposed with different exposure parameters in the same pattern, and after the exposure The relationship between the development of the substrate, the shape of the resist pattern formed by the development using the skier telometry technique, and the shape data measured by the skier telometry technique and the exposure parameters used There is provided an exposure condition correction method comprising: determining an optimum exposure parameter; and correcting an exposure condition so that a subsequent substrate is exposed with the optimum exposure parameter.

[0012] According to a second aspect of the present invention, a resist film forming unit that forms a resist film on a substrate, an exposure processing unit that exposes the resist film formed on the substrate in a predetermined pattern, and an exposure processing The development processing section that develops the developed substrate and the shape of the developed resist pattern A pattern shape measuring unit for measuring by a measurement technique, a first control unit for controlling the resist film forming unit, the development processing unit, and the pattern shape measuring unit; a second control unit for controlling the exposure processing unit; An interface for performing data communication between the first control unit and the second control unit, and the first control unit and the second control unit communicate data via the interface. A resist film is formed on the substrate, and multiple portions of the resist film are successively exposed while changing the exposure parameters in the same pattern, developed, and the shape of the formed resist pattern is measured by the skiterometry technique. The relationship between the measured shape data and the exposure parameters used The optimum exposure parameters are determined and exposure is determined with the optimum exposure parameters determined for the subsequent substrates. Provided is a substrate processing apparatus that performs control to correct exposure conditions so that light is emitted.

[0013] According to a third aspect of the present invention, a coating film forming unit that forms a resist film on a substrate, an exposure processing unit that exposes the resist film formed on the substrate in a predetermined pattern, and an exposure process Forming a resist film on a substrate using a substrate processing apparatus having a development processing unit that develops the substrate and a pattern shape measurement unit that measures shape data of the developed resist pattern by a skitometry technique; Sequential exposure of multiple parts of the resist film using the same pattern with different exposure parameters, development of the exposed substrate, and measurement of the shape of the resist pattern formed by development using the scan telometry technique Determining the optimum exposure parameter from the relationship between the measured shape data and the exposure parameter used, and determining the optimum exposure pattern for subsequent substrates. As processing including the method comprising compensation exposure conditions to the exposure in meter is executed, the computer program including software for the cause substrate processing apparatus control is control in a computer is provided.

In the present invention, the exposure amount and the focus value can be used as exposure parameters to be corrected in the exposure process, and the optimum focus value can be obtained by changing the focus value while keeping the exposure amount constant. It is possible to obtain the optimum exposure value and the optimum focus value by changing the exposure amount and the focus value, respectively.

[0015] The resist pattern shape measurement using the skier telometry technology irradiates light of a predetermined wavelength to a plurality of points having a predetermined positional relationship within one shot area of exposure on the substrate, and spectral reflection is performed at each point. The spectrum is measured, and the obtained spectral reflection spectrum is calculated in advance. It is preferable to obtain the line width of the resist pattern at that point by collating with the library configured by comparing the created spectral reflection spectrum and the line width of the resist pattern.

[0016] According to the present invention, a plurality of parts are exposed with the same pattern while changing the exposure parameters, and the shape of the resist pattern formed by the present image is measured by the skier telometry technique. Relationship with parameters Since the optimum exposure parameters are determined and the exposure conditions are corrected, it is not necessary to intervene manually for shape measurement or input to the exposure equipment. For this reason, it is possible to prevent human error from intervening in the correction of exposure conditions. In addition, since the correction conditions can be calculated in a short time by using the sky telometry technique, the exposure conditions can be checked more frequently than in the past. As a result, resist patterns can be formed with high accuracy, and product quality can be maintained at a high level.

[0017] Further, the above-described technique for constructing a library by comparing the spectral reflection spectrum prepared in advance with the line width of the resist pattern and collating the spectral reflection spectrum with the library, for example, exposure amount Is applied to the method to find the optimum focus value by changing the focus value, and the relationship between the obtained line width on the Y-axis and the focus value used on the X-axis. Since the line width value is a curve having a maximum value or a minimum value, for example, the average of the focus values giving the maximum value or the minimum value at each point can be set as the optimum focus value. Such calculation is automatically performed by a computer, and the calculated optimum focus value is directly transferred from the computer to the exposure apparatus so that the control unit corrects the exposure condition in the exposure apparatus. be able to.

Brief Description of Drawings

FIG. 1 is a plan view showing a schematic configuration of a resist coating / development processing system.

FIG. 2 is a front view showing a schematic configuration of a resist coating / development processing system.

FIG. 3 is a rear view showing a schematic configuration of a resist coating / developing system.

FIG. 4 is a diagram showing a control system for a resist coating / developing system and an exposure apparatus.

[Fig.5] Flowchart when the method of correcting the focus value and fixing the exposure value is applied FIG. 6 is a diagram showing exposure area setting forms and exposure order on a wafer.

FIG. 7 is a diagram showing a setting example of line width measurement points in an exposure area.

FIG. 8 is a graph showing the relationship between the line width of the resist pattern and the focus value.

FIG. 9 is a diagram showing a setting form of an exposure area, an exposure value, and a focus value on a wafer.

FIG. 10 is a graph showing the relationship between the line width and the focus value for each exposure amount.

FIG. 11 is a diagram showing resist pattern parameters that can be measured by the skier telometry technique. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a plan view showing a schematic configuration of a resist coating Z development processing system 1 for forming a resist film and developing a substrate after exposure, FIG. 2 is a front view thereof, and FIG. FIG. FIG. 1 shows a configuration in which the resist coating Z development processing system 1 and the exposure apparatus 14 are combined.

This resist coating Z development processing system 1 includes a cassette station 11 as a transfer station, a processing station 12 having a plurality of processing units, an exposure apparatus 14 and a processing station 12 provided adjacent to the processing station 12. And an interface station 13 for transferring the wafer W to and from the terminal.

In the cassette station 11, a wafer cassette (CR) containing a plurality of (for example, 25) wafers W is loaded and unloaded. On the cassette mounting table 20, a plurality (five in FIG. 1) of positioning protrusions 20a for mounting a wafer cassette (CR) are provided in one row along the X direction. The wafer cassette (CR) is placed with the wafer loading / unloading port facing the processing station 12 side.

The cassette station 11 includes a wafer transfer mechanism 21 having a wafer transfer pick 21a. The pick 21a for wafer transfer can selectively access any one of the wafer cassettes (CR), and a transition unit (TRS-G) provided in the third processing unit group G of the processing station 12 described later. ) Can be accessed.

3 3

The processing station 12 has a third processing unit group G, a fourth processing unit group G, and a fifth processing unit group G in order from the cassette station 11 side on the rear side of the system (upper side in FIG. 1). I have. In addition, the first main transport unit is disposed between the third processing unit group G and the fourth processing unit group G.

3 4

A is provided, and the second main transport unit is disposed between the fourth processing unit group G and the fifth processing unit group G.

1 4 5

A is provided. In addition, on the front side of the system (lower side of Fig. 1), the cassette station 11

2

In order from the side, a first processing unit group G and a second processing unit group G are provided.

1 2

[0025] In the third processing unit group G, a high temperature heat treatment unit (BA

Three

KE), a high-precision temperature control unit (CPL-G) that controls the temperature of the wafer W with high accuracy,

Three

A transition unit (TRS-G) serving as a wafer W transfer unit between the cassette station 11 and the first main transfer unit A1 is stacked in, for example, 10 stages.

Three

In the fourth processing unit group G, for example, a heat treatment is performed on the wafer W after resist application.

Four

A pre-beta unit (PAB), a post-bake unit (POST) that heat-processes the developed wafer W, and a high-precision temperature control unit (CPL-G), for example, are stacked in 10 steps.

Four

. In the fifth processing unit group G, for example, heat treatment is performed on the wafer W after exposure and before development.

Five

Post-exposure bake unit (PEB), high-precision temperature control unit (CPL-G)

5 For example, 10 layers are stacked.

On the back side of the first main transfer part A, a sixth processing unit group G having an adhesion unit (AD) and a heating unit (HP) for heating the wafer W is provided. Second main

6

On the back side of the transfer unit A, a peripheral exposure device that selectively exposes the edge of the wafer W (

2

(WEE), a line width measuring device (ODP) for measuring the line width of a resist pattern by a scan telometry technique, and a film thickness measuring device (FTI) for measuring a resist film thickness. G group G is provided.

[0028] In the first processing unit group G, three resist coating units (COT) for forming a resist film and a bottom coating unit (BARC) for forming an antireflection film are stacked in a total of five stages. In FIG. 1, “CP” indicates a coater cup, and “SP” indicates a spin chuck. In the second processing unit group G, development units (DEV) are stacked in five stages.

2

A first main wafer transfer unit 16 is provided in the first main transfer unit A. The first main wafer transfer device 16 includes three arms for holding the wafer W. These arms rotate integrally around the Z axis, move up and down in the Z axis direction, and separately in the horizontal direction. Stretchable (in the XY plane). As a result, the first main wafer transfer device 16 is connected to the first processing unit group G and the third processing unit. Selectable for each of the physical unit group G, the fourth processing unit group G, and the sixth processing unit group G

3 4 6 is accessible. The second main transfer unit A has the same configuration as the first main wafer transfer unit 16.

2

A second main wafer transfer device 17 having a structure is provided. The second main wafer transfer device 17 includes a second processing unit group G, a fourth processing unit group G, a fifth processing unit group G, and a seventh processing unit.

2 4 5

Each unit of the knit group G can be selectively accessed.

[0030] Between the first processing unit group G and the cassette station 11 and the second processing unit group G

1 2 Between the interface station 13 and the temperature control pumps 24 and 25 for supplying the processing liquid to the first and second processing unit groups G and G, respectively, and the resist coating Z developing processing system 1

2

For supplying clean air from each air conditioner to each processing unit group G to G

1 5

Tato 28, 29 forces are provided.

[0031] At the lowest stage of each of the first and second processing unit groups G 1 and G, a chemical solution is supplied to them.

1 2

Chemical units (CHM) 26 and 27 are provided. A first control unit 31 that controls the resist coating Z development processing system 1 as a whole is provided below the cassette station 11.

[0032] The rear panel and the first processing unit group G to the seventh processing unit group G of the processing station 12 can be removed for maintenance.

[0033] The interface station 13 includes a first interface station 13a on the processing station 12 side and a second interface station 13b on the exposure apparatus 14 side. The first interface station 13a has an opening for the fifth processing unit group G.

A first wafer carrier 18 is arranged so as to face 5, and a second wafer carrier 19 which is movable in the X direction is arranged at the second interface station 13 b.

[0034] On the back side of the first wafer transfer body 18, in the order of the upper force, the peripheral exposure apparatus (WEE), the in-buffer cassette (INBR) that temporarily stores the wafer W transferred to the exposure apparatus 14, and the exposure apparatus An eighth processing unit group G is provided in which out-out buffer cassettes (OUTBR) for temporarily storing the wafers W that have been unloaded are stacked. First wafer carrier 18 positive

8

On the surface side, the upper force is also in order, with a transition unit (TRS-G) and two stages of high-precision temperature control

9

A ninth processing unit group G is provided, in which stacks (CPL-G) are stacked.

9 9

The first wafer transfer body 18 has a fork 18a for wafer transfer. This four 18a includes the fifth processing unit group G, the eighth processing unit group G, and the ninth processing unit group G.

5 8 9 Access the unit and transfer the wafer W between each unit. Further, the second wafer transport body 19 has a fork 19a for wafer transfer. The fork 19a includes the units of the ninth processing unit group G, the in-stage 14a and the out-stay of the exposure apparatus 14.

9

14b is accessible, and the wafer W is transferred between these parts.

It should be noted that the instage 14a of the exposure apparatus 14 is capable of carrying in the wafer W with a lamp isometric force indicating that Z is not possible. The outstage 14b is provided with a lamp or the like indicating that the wafer W can be unloaded and Z is not possible. (2) The interface station 13b is provided with a sensor for recognizing the display state of these lamps. The fork 19a holding the wafer W carries the wafer W into the in-stage 14a according to the recognition result of this sensor, and the empty fork 19a is configured to access the outstage 14b and carry out the wafer W according to the recognition result of the sensor.

[0037] In the resist coating Z development processing system 1 configured as described above, the wafer cassette

One wafer W taken out from (CR) is transferred to, for example, the transition unit (TRS-G) of the processing station 12, and temperature control and adhesion control in the temperature control unit (TCP) are performed.

Three

Adhesion treatment in knit (AD), formation of anti-reflection film in bottom coating unit (BARC), heat treatment in heating unit (HP), beta treatment in high temperature heat treatment unit (BAKE), high precision temperature control unit ( Temperature control with CPL-G), resist coating tool

Three

The resist solution is applied to the exposure apparatus 14 after undergoing a resist solution coating process at the COT, a pre-beta process at the pre-beta unit (PAB), and a peripheral exposure process at the peripheral exposure apparatus (WEE). Then, the wafer W is exposed to the transition unit (TRS-G) after exposure by the exposure apparatus 14.

9 After transport, post-exposure bake processing in post-exposure beta unit (PEB), development processing in development unit (DEV), post-beta processing in post-beta unit (POST), wafer cassette (CR) Returned to

Next, the control system of the resist coating Z development processing system 1 and the exposure apparatus 14 will be described with reference to FIG. The resist coating Z development processing system 1 is controlled by the first control unit 31, and the exposure apparatus 14 is controlled by the second control unit 32.

[0039] The first control unit 31 includes a first process controller (CPU) 35 and a process manager who applies resist coating. A keyboard that performs command input operations to manage the fabric / development processing system 1 is applied to the keyboard. Z The first data input / output unit 36 having a display that visualizes and displays the operation status of the development processing system 1, and the registered Recipe 38b, which is data for executing the control program 38a and control program 38a for executing each processing condition executed in the coating Z development processing system 1 under the control of the first process controller (CPU) 35 An analysis program 39a for analyzing the spectral reflection spectrum measured by the line width measuring device (ODP), and a first recording unit 37 in which a library (database) 39b is recorded.

[0040] The library 39b is a database in which the diffracted light intensity distribution is obtained by computer simulation for an arbitrary pattern shape, and the spectral reflection spectrum and the resist pattern shape are linked. The data recorded in this library 39b was obtained by actually patterning a resist film under specified conditions, measuring the spectral reflection spectrum of the pattern, confirming the shape by SEM observation, and improving reliability. Is preferred. However, this applies only to line widths that can be observed well with SEM observation.

[0041] Note that FIG. 4 illustrates a part of the processing units and the like controlled by the first control unit 31, and all the control targets are illustrated.

[0042] The second control unit 32 visualizes the operating status of the second process controller (CPU) 41, the keyboard on which the process manager performs command input operations to manage the exposure apparatus 14 and the exposure apparatus 14. A control program 44a and a recipe for executing each processing condition executed by the exposure apparatus 14 under the control of a second process controller (CPU) 41 and a second data input / output unit 42 having a display for displaying And a second recording section 43 in which 44b is recorded. Drive unit in the exposure apparatus 14 from the second process controller (CPU) 41 (for example, a mechanism for adjusting the position of the wafer W or the lens position for adjusting the focus, a mechanism for adjusting the amount of light, etc.) ) Is sent to the control signal.

In order to perform the process for correcting the exposure parameter in the exposure apparatus 14, a bidirectional communication power interface 33 for data related to the exposure process is provided between the first control unit 31 and the second control unit 32. Is going to be done through. This will be described in detail later. [0044] Before processing the wafer W as a product using the resist coating and developing system 1 and the exposure apparatus 14, a dummy wafer is used to form a resist film, perform exposure with a test pattern, and develop the wafer. Then, measure the line width (CD) of the developed pattern to confirm the exposure conditions. If the exposure conditions are judged to be inappropriate, correct the exposure conditions. Next, a method for correcting the exposure conditions of the exposure apparatus 14 by the resist coating / development processing system 1 and the exposure apparatus 14 will be described.

FIG. 5 shows a flowchart of a method for correcting the focus value as another exposure parameter while fixing the exposure amount as one of the exposure parameters. First, a resist film is formed on the surface of the dummy wafer W (Step 1). The dummy weno, W, should be as uniform as possible and have a high degree of flatness. This is because if the surface of the dummy wafer W itself has irregularities, or if the thickness is uneven and the surface is inclined, the exact exposure conditions cannot be determined.

Next, the resist film formed on the dummy wafer W is sequentially exposed by changing the focus value with the test pattern (step 2). In this step 2, the exposure dose is determined under the conditions that have the least manufacturing margin at the production site, for example, the exposure dose that can form 65 nmLZS (hereinafter referred to as `` exposure dose E '').

To 0).

[0047] On the other hand, the focus value is set for manufacturing the product !, and the focus value (hereinafter referred to as “focus value F”) is set to be vertical and horizontal as shown in FIG. 6, for example. Multiple

0

While moving the exposure area S with a single stroke, the focus value is F within the range of ± 0.5 m.

0

. Shift the focus value by 05 m and perform one shot exposure for each exposure area S. The area of the exposure area S is preferably matched to the maximum field size of the exposure device 14.

[0048] Next, the wafer W that has been exposed in this way is developed (step 3). As a result, a pattern is formed on the resist film, and the line width of this resist pattern is measured using a line width measuring device (ODP) (step 4). The line width measurement in this line width measuring device (ODP) is generally performed as follows. First, as shown in FIG. 7, a plurality of measurement points within one exposure area S, for example, a total of 5 points (P

Set 1 ~ P). Next, light of a predetermined wavelength is applied to the point P, and the spectral reflection spectrum is measured. Then, the spectrum with the closest shape to the obtained spectral reflectance spectrum is selected as the spectral reflectance spectrum of Library 39b. The line width of the resist pattern at point P is obtained by searching for Kutulka. Point P

1 2 ~

The same process is performed for P, and the line width of the resist pattern is obtained for each point. further,

Five

Such spectral reflection spectrum measurement and line width determination are performed for each exposure area s.

[0049] Next, the first control unit 31 is used when the line width of the resist pattern of the points P to P set in each exposure area S and each exposure area S are exposed using the analysis program 39a. Fo

1 5

Find the relationship with the single value (Step 5). This gives the graph shown in FIG. For this step 5, it is sent from the second controller 32 of the exposure apparatus 14 to the first controller 31 via the exposure condition force S interface 33 in each exposure area S.

[0050] For example, in the case of a positive resist, the exposed portion of the resist film dissolves during development, and therefore, when the focus value is not appropriate, the exposed range is widened, thereby increasing the groove width. As it becomes wider, the line width becomes narrower. Therefore, as shown in FIG. 8, for each of the points P to P, a curve is drawn in which the line width is maximum at a portion where the focus value is appropriate.

Five

In the case of a negative resist, a curve is drawn so that the line width is minimal at an appropriate focus value.

[0051] The first control unit 31 is a force that gives the maximum value of a total of five curves obtained at points P to P.

1 5

The average value of the minimum and maximum focus values F and F is determined as the optimum focus value F.

min max B

6). Note that point P

Each focus that gives the maximum value of a total of 5 curves obtained every 1 to P

Five

The average value may be determined as the optimum focus value F.

B

[0052] Next, the absolute difference between the optimum focus value F and the focus value F determined in this way

B 0

It is determined whether or not the value f satisfies a force force that is equal to or smaller than a preset allowable value δ, that is, f≤δ (step 7). If f≤ δ is satisfied, the focus value is not corrected, and exposure processing of the wafer W as a product is started without changing F (step 8).

0

[0053] On the other hand, when f≤δ is not satisfied, the optimum focus value F and the focus value F are

The absolute value f of the difference of 1 Β 0 is a dummy weno whose value is greater than the allowable value δ.Warning value that is estimated to be abnormal in a series of processing of W. Meet

Determine whether 2 1 2 (step 9).

[0054] If δ satisfies δ, the force required to perform exposure of wafer W as a product

1 2

The exposure apparatus 14 is corrected so that the focus value is the focus value F (step 10). Exposure equipment The focus value correction in 14 is directly transmitted from the first control unit 31 to the second control unit 32 via the focus value correction signal force ^s interface 33, and the second control unit 32 determines the exposure apparatus based on this correction signal. Correct the exposure conditions in step 14. When the focus value is corrected in the exposure apparatus 14, the exposure processing of the wafer W as the product in step 8 is started.

[0055] If δ is not satisfied and δ is not satisfied, that is, the optimum focus value F and the focus value F are

1 If the absolute value f of the difference between 2 and 0 is greater than or equal to the warning value δ,

2

An alarm (for example, sound, light, display on the first data input / output unit 36, etc.) is issued to warn the process manager of the system abnormality (step 11). In response to this warning, the process manager inspects the resist coating / development processing system 1 and the exposure device 14 (step 12) .ο After the system abnormality is resolved, the optimum focus value from step 1 is again checked. In order to decide, the processing of the dummy wafer W is started.

[0056] Conventionally, since data relating to exposure conditions has not been transmitted and received between the exposure apparatus and the resist coating / development processing system, the process manager determines the focus value of each exposure area. The power of the exposure device was read and the data was input to the resist coating and development system, and the optimum focus value obtained as a result was read and input to the exposure device. For this reason, input errors such as reverse input of positive and negative signs and misalignment of the decimal point occur in data input work, etc., and the exposure apparatus is not properly corrected, resulting in product defects. However, as described above, the above-mentioned problems can be prevented by correcting the exposure conditions by directly transmitting / receiving data on the exposure conditions between the resist coating / developing system 1 and the exposure apparatus 14. As a result, product defects can be prevented.

In the exposure parameter correction method of the exposure apparatus 14 described above, the force exposure amount and the focus value that are corrected only for the focus value can be set as correction targets.

An exposure parameter correction method at that time will be described below.

First, a resist film is formed on the surface of the dummy wafer W with a uniform thickness and high flatness, and this resist film is sequentially exposed by changing an exposure amount and a focus value with a test pattern. Here, as shown in FIG. 9, the dummy wafer W is provided with an exposure area S divided vertically and horizontally, and the horizontal direction Then, with the exposure amount E set for product manufacture as the center, for example, the exposure amount E

0 -3

Change the exposure with ~ E. In the vertical direction, the focus value F is the center.

+ 3 0

The focus value is changed in the range of the residue values F to F.

-4 +4

Subsequently, the wafer W that has been exposed is developed. As a result, a pattern is formed on the resist film. For example, the line width of the resist pattern at the center of each exposure area is measured according to the measurement method described above using the line width measuring device (ODP), and the exposure is performed. The relationship between the line width and the focus value is obtained for each amount E_ to E. This makes the graph shown in Figure 10

3 + 3

can get.

In FIG. 10, curves E to E correspond to exposure amounts E to E, respectively. Curve E

-3 +3-3 +3 -3

Medium power of ~ E The change of line width (CD) is gradual with respect to the change of focus value, and

+ 3

, The curve close to the desired line width W, in Fig. 10, the exposure of curve E is set to the optimal exposure E

0 + 1 B Determine. Also, the minimum value of this curve E (or the maximum value if the selected curve is convex upward)

+ 1

Is determined as the optimum focus value F.

B

[0062] When the LER increases, in the measurement by SEM, for example, when trying to obtain the graph shown in Fig. 10, each curve becomes a jagged line, so it is difficult to determine the maximum and minimum values of each curve. It becomes difficult to determine the optimum focus value. On the other hand, according to the skier telometry technology, LER has almost no sensitivity and is not affected by it, and a high-accuracy smooth graph such as that shown in FIG. 10 can be obtained. Makes decisions easier.

[0063] The difference f between the optimum focus value F and the focus value F determined in this way is the range of the tolerance δ.

If it is within the range of 0 1, the focus value is not corrected, and the optimum focus value F and focus value F

差 If the difference f of 0 is greater than the tolerance δ and less than the warning range δ, the first control unit 31

1 2

Directly transmitted to the control unit 32 via the correction signal force interface 33 for the focus value.The second control unit 32 corrects the focus value of the exposure apparatus 14 to the optimum focus value F based on this correction signal, and the optimum focus value. Difference between F and focus value F is from warning range δ

If Β Β 0 2 is also larger, the first control unit 31 issues an alarm. In the above example, since the optimum exposure amount Ε is not the initial set exposure value Ε, the exposure is performed from the first control unit 31 to the second control unit 32.

Β 0

The correction signal force of the value is transmitted directly via the S interface 33, and the second control unit 32 Based on the positive signal, the exposure condition in the exposure apparatus 14 is corrected. Of course, the optimal exposure E

B

If is the initially set exposure value E, the exposure dose is not corrected.

0

It should be noted that the embodiment described above is intended to clarify the technical contents of the present invention, and the present invention is construed as being limited only to such specific examples. However, various modifications can be made without departing from the spirit of the present invention and the scope described in the claims.

[0065] For example, in the above description, when using the force skiterometry technique in which the line width of the resist pattern is an index for correcting the exposure amount and the focus value as exposure parameters, as shown in FIG. Not only the line width (CD) but also the bottom width (C), tilt angle Θ, and resist film thickness (D) of the resist pattern can be measured. For example, a certain line width (CD) Determine the range of the focus value to be obtained, and then sequentially select the focus value range in which the inclination angle Θ is good, select the center value of the focus value among them, and finalize it. Alternatively, the optimum focus value F may be determined.

B

Further, from the result shown in FIG. 8, the tilt state of the wafer W during the exposure process can also be detected, and the result is fed back to the exposure apparatus 14 so that the exposure condition is corrected. You can also. Furthermore, when the resist pattern force obtained by changing the exposure amount and focus value respectively corrects the exposure amount and focus value, the curve E in FIG.

-3

Calculate the focus value that gives the maximum or minimum value every ~ E, and calculate the average value

+ 3

The optimum focus value F may be used. When correcting the amount of exposure, it is possible to

B

Since different results are expected, it is preferable to verify the exposure conditions for each modified illumination condition.

Furthermore, in the above embodiment, the case where the present invention is applied to a semiconductor wafer has been described. However, the present invention is also applicable to a photolithography technique on a glass substrate for FPD (flat panel display) typified by a liquid crystal display device. Can do. Furthermore, in the above-described embodiment, the line width measuring device (ODP) is arranged at a position where it can be transferred by the main transfer device. However, the resist coating and development processing system 1 in the X direction can be accessed so that the wafer transfer mechanism 21 can be accessed. It may be attached to the opposite side.

Industrial applicability The present invention is suitable for improving the accuracy of resist patterns when manufacturing semiconductor devices and FPDs.

Claims

The scope of the claims

[1] forming a resist film on the substrate;

Sequentially exposing a plurality of portions of the resist film by changing exposure parameters in the same pattern;

Developing the exposed substrate;

Measuring the shape of the resist pattern formed by development using the skier telometry technique;

The relationship between the shape data measured by the skier telometry technique and the exposure parameters used; determining the optimal exposure parameters;

Correcting exposure conditions so that subsequent substrates are exposed with the optimum exposure parameters;

An exposure condition correction method comprising:

[2] The exposure condition correction method according to claim 1, wherein the exposure parameters are an exposure amount and a force value, and the exposure value is constant and the focus value is changed during the sequential exposure. Correction method.

3. The exposure condition correction method according to claim 1, wherein the exposure parameters are an exposure amount and a force value, and the exposure amount and the focus value are respectively changed during the sequential exposure.

[4] The exposure condition correction method according to claim 1, wherein the shape measurement of the resist pattern by the skier telometry technique is performed.

A plurality of points having a predetermined positional relationship in one shot area of exposure on the substrate are irradiated with light of a predetermined wavelength, a spectral reflection spectrum is measured at each point, and the obtained spectral reflection spectrum is preliminarily obtained. An exposure condition correction method that is performed by checking a line width of a resist pattern at a point by comparing with a library configured by comparing a created spectral reflection spectrum with a line width of a resist pattern.

5. The exposure condition correction method according to claim 1, wherein the data relating to the optimum exposure parameter is communicated from a calculation unit that determines the optimum exposure parameter to a control unit of an apparatus that performs an exposure process.

[6] a resist film forming portion for forming a resist film on the substrate;

An exposure processing unit that exposes a resist film formed on the substrate in a predetermined pattern; a development processing unit that develops the exposed substrate;

A pattern shape measuring unit for measuring the shape of the developed resist pattern by a skier telometry technique;

A first control unit that controls the resist film forming unit, the development processing unit, and the pattern shape measurement unit;

A second control unit for controlling the exposure processing unit;

An interface for performing data communication between the first control unit and the second control unit;

Comprising

The first control unit and the second control unit form a resist film on the substrate while performing data communication via the interface, and sequentially expose a plurality of portions of the resist film in the same pattern while changing exposure parameters. Then, the shape of the resist pattern formed and developed is measured by the skiterometry technique, and the optimum exposure parameters are determined from the relationship between the measured shape data and the used exposure parameters, and are applied to the subsequent substrates. Therefore, the substrate processing apparatus performs control to correct the exposure conditions so that the exposure is performed with the optimum exposure parameters determined in this way.

[7] In the substrate processing apparatus according to claim 6, the exposure parameter is an exposure amount and a focus value, and the second control unit performs the sequential exposure by changing the focus value while keeping the exposure amount constant. A substrate processing apparatus for controlling the exposure processing unit to be performed.

[8] The substrate processing apparatus of claim 7,

The first control unit includes a recording unit in which a library configured by comparing a spectral reflection spectrum obtained by applying light of a predetermined wavelength to a resist pattern having a known line width and the line width is recorded. The pattern shape measuring unit is controlled so that light having a predetermined wavelength is applied to a plurality of points in a predetermined positional relationship within one shot region of exposure on the substrate, and a spectral reflection spectrum is measured at each point, Further, by comparing the spectral reflection vector obtained thereby with the library, the line of the resist pattern at each point is obtained. The optimum exposure parameter is determined from the relationship between the line width thus obtained and the exposure parameter sent from the second control unit, and data relating to the determined optimum exposure parameter is obtained. Feedback to the second control unit,

The substrate processing apparatus, wherein the second control unit corrects an exposure condition in the exposure processing unit based on data relating to an optimum exposure parameter transmitted from the first control unit.

[9] In the substrate processing apparatus according to claim 6, the exposure parameters are an exposure amount and a focus value, and the second control unit sequentially performs exposure by changing the exposure amount and the focus value, respectively. A substrate processing apparatus for controlling the exposure processing unit.

[10] The substrate processing apparatus of claim 9,

The first control unit includes a recording unit in which a library configured by comparing a spectral reflection spectrum obtained by applying light of a predetermined wavelength to a resist pattern having a known line width and the line width is recorded. The pattern shape measuring unit is controlled so that light having a predetermined wavelength is applied to a plurality of points in a predetermined positional relationship within one shot region of exposure on the substrate, and a spectral reflection spectrum is measured at each point, Further, by comparing the spectral reflection vector obtained in this way with the library, the line width of the resist pattern at each point is obtained, and the line width thus obtained and the exposure parameters sent from the second control unit are obtained. The optimum exposure parameter is determined from the relationship with the data, and data relating to the determined optimum exposure parameter is fed back to the second control unit,

[11] A coating film forming unit that forms a resist film on the substrate, an exposure processing unit that exposes the resist film formed on the substrate in a predetermined pattern, and a development processing unit that develops the exposed substrate. Using a substrate processing apparatus having a pattern shape measuring unit for measuring the shape data of the resist pattern using a scan telometry technique,

Forming a resist film on the substrate;

Developing the exposed substrate; Measuring the shape of the resist pattern formed by development using the skier telometry technique;

The relationship between the measured shape data and the exposure parameters used; determining the optimal exposure parameters;

A computer program including software for causing a computer to control the substrate processing apparatus so that a process including correcting the exposure conditions in order to expose a subsequent substrate with the optimum exposure parameters is executed.

12. The computer program according to claim 11, wherein the exposure parameters are an exposure amount and a focus value, and the sequential exposure changes a focus value with a constant exposure amount.

13. The computer program according to claim 11, wherein the exposure parameters are an exposure amount and a focus value, and the sequential exposure changes the exposure amount and the focus value, respectively.

14. The computer program according to claim 11, wherein the shape measurement of the resist pattern by the skier telometry technique is performed by applying light of a predetermined wavelength to a plurality of points in a predetermined positional relationship within one shot region of exposure on the substrate. Spectral reflection spectrum is measured at each point, and the obtained spectral reflection spectrum is compared with a library configured by comparing the spectral reflection spectrum created in advance with the line width of the resist pattern. And a computer program executed by calculating the line width of the resist pattern at each point.