JP2003151889A - Aligning method and apparatus thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To propose a system that inexpensively adapts contradictory performance of high speed operation and high throughput, and, in addition, to propose a system that performs an alignment method corresponding to a process error simultaneously with an increased speed in focus offsetting, and impurity inspection at the periphery section of a wafer. SOLUTION: In the alignment method, a wafer is vacuum-chucked by a chuck outside an projection aligner, a mark is arranged on the chuck, the relative relationship of the direction axis of each shot of the wafer to the mark on the chuck is measured, conveyance to the projection aligner is performed for each chuck, and merely the mark on the chuck is measured for exposing in the projection aligner. In alignment measurement, shape measurement is conducted in the presence or absence of a resist, and an alignment error can also be calculated by signal simulation. A focus offset is also measured outside the projection aligner, the information of the measurement is reflected to the projection aligner, and exposure is performed, thus achieving a system having high accuracy and throughput. Impurity inspection is also carried out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positioning method and apparatus, and more particularly to an exposure apparatus for semiconductor manufacturing.
IC and LS formed on the reticle surface as an object
The present invention relates to an alignment device for performing relative alignment (alignment) of a fine electronic circuit pattern such as I or VLSI with a wafer as a second object.

Most of the exposure apparatuses are currently called steppers or scanners. However, in the present specification, the exposure apparatus will be referred to as "exposure apparatus" if no special distinction is required.

[0003]

2. Description of the Related Art In a projection exposure apparatus for manufacturing semiconductors, it is required that a circuit pattern on a reticle surface can be projected and exposed on a wafer surface with higher resolution as the integrated circuit becomes finer and higher in density. Since the projection resolution of the circuit pattern depends on the numerical aperture (NA) of the projection optical system and the exposure wavelength, a method of fixing the exposure wavelength to increase the NA of the projection optical system or a shorter exposure wavelength, for example, g
Line, i line, excimer laser oscillation wavelength from i line, and also for excimer laser oscillation wavelength, we are studying an exposure method using 248 nm, 193 nm, and even 157 nm, and an exposure wavelength of 193 nm has already been commercialized. There is.

On the other hand, with the miniaturization of circuit patterns, it has been required to align a reticle on which an electronic circuit pattern is formed with a wafer with high precision.

WIS which is one of the alignment errors
Offs is a method for eliminating a process error called (Wafer Induced Shift).
The applicant of the present invention has proposed a system called etAnalyzer (Japanese Patent Application No. 10-356940).

First, regarding WIS, as an example, the metal CMP (Chemical Mechanical) recently introduced is caused by the asymmetry of the alignment mark shape and the resist shape thereon due to a process error.
In the flattening process such as the al polishing process, the structure of the alignment mark is often asymmetrical, and the global alignment causes a rotation error in FIG. 1 and a magnification error in FIG. .

FIG. 3 shows a line A above the actual alignment mark.
FM (Atomic Force Microscope)
7 shows the data measured by roscopy).

This signal has a resist, and the structure of the alignment mark is called the metal CMP shown in FIG. As can be seen in FIG. 3, the resist shapes on the alignment marks in the left and right shots of the wafer 1 and in the middle shot are symmetrical in surface shape in the middle shot, but the surface shapes in the left and right shots are asymmetrical, It can be seen that the asymmetry is reversed on the left and right.

This is WIS.

Therefore, the Offset Analyzer
In order to perform relative alignment between the wafer 1 and the reticle 12, the position of the wafer 1 is detected by the alignment detection system of the non-exposure light TTL Offaxis system with high baseline stability. Before and after the resist coating, the surface shape before and after the resist coating is performed by a profiler such as AFM outside the aligning device (= exposure device) with the same plural mark shapes used for alignment on the wafer 1.
(Three-dimensional shape measuring instrument) measures the offset when the three-dimensional relative positional relationship between the resist and the wafer mark is adjusted to match the signal of the detection system of the alignment device, and the value is calculated. This is a proposal of a method for eliminating the accuracy deterioration caused by the asymmetry of the alignment mark shape and the resist shape by the above-mentioned process by using and aligning.

With this Offset Analyzer, it is possible to realize a highly accurate and stable alignment method in which there is little baseline variation in correspondence with WIS.

[0012] Referring to Figure 5, the Offset Analysis
The flow of the wafer 1 and information in the zer will be described.

As shown in FIG. 5, the wafer 1 is carried to the Offset Analyzer before the resist is applied, and the shape of the alignment mark on the wafer 1 is measured by the profiler.

Next, as shown in FIG. 5, the wafer 1 is carried to a coater to apply a resist, and the resist is applied.

Next, as shown in FIG. 5, the wafer 1 is carried to the Offset Analyzer again, and the surface shape of the resist on the alignment mark is profiled by the Profiler.
Measure with.

At that time, the alignment detection system configured in the Offset Analyzer detects the alignment signals of a plurality of alignment marks arranged in each shot on the wafer 1 for detecting the X and Y directions.

Next, the offset amount generated by the signal simulator in the Offset Analyzer is calculated. In the method of calculating the offset amount, first, it is necessary to match the three-dimensional relative positional relationship between the resist and the wafer mark. The three-dimensional relative positional relationship between the resist and the wafer mark is changed, and the relationship where the result of the signal simulator matches the signal of the alignment mark is the three-dimensional relative positional relationship between the resist and the wafer mark. An alignment signal is obtained using the relative relationship at this time, an offset for alignment measurement is calculated from the alignment signal, and the value is sent to the exposure apparatus.

Alignment and exposure are performed by an exposure device based on this offset, and after the exposure of all shots is completed, the wafer 1 is conveyed to a developer for development.

Next, FIG. 6 shows the Offset Analysis.
The configuration of er is shown.

The Offset Analyzer includes a chuck that supports the wafer 1, a three-dimensional movement, and an X-axis.
YZ stage, Profiler for measuring surface shape with / without resist, Two-dimensional position detection system equivalent to alignment scope configured in exposure equipment, focus detection system, offset analyzer as a whole, and alignment offset from surface shape It is composed of a CPU that owns a simulator for calculating (the wafer 1 transfer system and the like are not shown).

At this time, the Offset Analyzer
Error of the alignment scope of the detection system and the exposure apparatus (= TIS: Tool Induced Shift)
Need to know the information. For example, the decentering coma aberration of the optical system and the uniformity of the illumination system correspond to this.

The alignment scope of the exposure apparatus may be in a state in which there is no error until it can be ignored, or the alignment scope of the exposure apparatus and the Offset Analysis.
It is also possible to make the alignment detection system of the zer have the same error.

As a method of evaluating this TIS, the applicant has already proposed a method as disclosed in JP-A-9-280186, and its effect has been confirmed in practice.

Further, if the apparatus error information of the alignment scope of the exposure apparatus is known, Offset An is set.
Without configuring the same alignment detection system as the alignment scope of the exposure apparatus in the aligner (for example, Offse
t Analyzer is the bright field detection system, and the exposure device is the dark field detection system.
The offset may be calculated.

This Offset Analyzer is
It is configured separately from the exposure device, which is an exposure device, and a plurality of exposure devices (not necessarily equal to the number of exposure devices) for calculating the alignment offset in a sequence that does not interfere with the exposure of the exposure device. Of Offset Anal
It is effective in terms of throughput to configure the yzer.

At the time of processes other than the first mask, after the alignment is completed, offset analyzer correction is used to calculate the wafer magnification, the orthogonality, the reduction magnification, etc. of the shot array lattice on the wafer 1 to be measured, and the reticle 12 surface. Wafer 1 with the above electronic circuit pattern
At the time of transfer, the wafer stage 21 or the reticle stage is driven to perform sequential exposure.

[0027]

The Offset Analyzer is considered to be able to exert a sufficiently large effect in the sense of being compatible with WIS, but it is Of in the exposure system as a whole.
Since the fset Analyzer is added, it is inevitable that the exposure system plus the Offset Analyzer up to now is considered as the exposure system, which causes a problem that the apparatus cost increases.

In particular, it is necessary to manage the TIS which is an error between the offset analyzer and the alignment detection system in the exposure apparatus, which requires high-precision optics, mechanical parts, and adjustments, which causes a rise in apparatus cost.

The present invention has been made by paying attention to the above points, does not cause a problem of reduction in throughput, is stable without being affected by various processes, and is capable of highly accurate wafer alignment. It is an object of the present invention to provide a positioning method and an apparatus capable of achieving the above without increasing the apparatus cost.

[0030]

In the present invention, Of
By adding the fset Analyzer, a proposal is made to solve the problem that the device cost of the exposure system in a broad sense increases.

In particular, this is a proposal of a system which does not need to take the TIS which is an error of the alignment detection system in the exposure apparatus, and an Offset Analyzer is added by that, but in order to reduce the apparatus cost of the exposure system in a broad sense. It is a suggestion.

In the alignment method of the present invention, the shapes of the same plurality of alignment marks used for alignment on the wafer are determined by a system (= Offset) outside the exposure apparatus.
In the (Analyzer), a position detection system for detecting the positions of a plurality of alignment marks and a three-dimensional shape measuring device for measuring the shape of the alignment marks are arranged, and the wafer is pointed to by a suction member in a system outside the exposure apparatus. The shape of multiple alignment marks on the wafer can be measured with a three-dimensional shape measuring instrument before and after resist coating, and the three-dimensional position placed on the suction member can be measured and the three-dimensional alignment marks on the wafer. The relative position is measured by a position detection system outside the exposure apparatus, the offset generated from that information is calculated, and the wafer is held by the suction member and moved to the exposure apparatus to determine the three-dimensional position inside the exposure apparatus. With the measurable detection system, only the mark on the suction member is measured, the reticle and the wafer are aligned, and the exposure is performed. Eliminating the accuracy deterioration caused by the alignment mark shape becomes asymmetrical due process, and is intended to propose a method to reduce the cost of the entire exposure system.

The present invention can be summarized in the following configurations if summarized and summarized as described above.

(1) In an exposure apparatus for transferring a pattern of a first object onto a second object in a relative position, a position detection system for detecting the positions of a plurality of marks on the second object outside the exposure apparatus. A three-dimensional shape measuring instrument for measuring the shapes of the plurality of marks is arranged, the second object is supported by a suction member, and the shapes of the plurality of marks on the second object are measured by the three-dimensional shape measuring instrument. And the three-dimensional relative position between the mark that can measure the three-dimensional position arranged on the suction member and the plurality of marks on the second object is measured by the position detection system and generated from the information. An offset is calculated, and the second object is moved to the exposure apparatus while being attracted to the suction member, and a detection system capable of measuring a three-dimensional position in the exposure apparatus is used to move the second object on the suction member. Measure only the mark, The alignment of the serial first object and the second object, positioning method, wherein the exposing.

(2) When exposing a plurality of second objects,
The alignment method according to (1) above, wherein an offset is measured for the first second object and the same offset is used for the second and subsequent sheets.

(3) The alignment method according to (1) above, wherein the foreign matter inspection on the second object is also performed outside the exposure apparatus before and after the application of the photosensitive material for exposure.

(4) The alignment method according to (1), wherein the offset generated at the time of measuring the focus of the second object is also measured outside the exposure apparatus after coating the photosensitive material for exposure.

(5) The alignment method according to (4), wherein the focus offset is obtained outside the exposure apparatus by a non-optical measurement system.

(6) The shape of the plurality of marks on the second object is set outside the exposure apparatus before the application of the photosensitive material for exposure to the second mark.
The shape of the plurality of marks on the object is measured by the three-dimensional shape measuring instrument, and the shape of the plurality of marks on the second object is measured by the three-dimensional shape measuring instrument even after applying the photosensitive material. The alignment method according to (1) above.

(7) Atomic force microscope (AF) is used to calibrate the shapes of a plurality of marks on the second object outside the exposure apparatus.
M: Atomic Force Microscope
The alignment method according to (6) above, wherein the surface shape is measured by e).

(8) Positioning according to the above (6), characterized in that the surface shape is measured by a stylus type three-dimensional shape measuring instrument during calibration of the shape of a plurality of marks on the second object outside the exposure apparatus. Method.

(9) The surface shape is measured by optical three-dimensional measurement calibrated by a non-light three-dimensional shape measurement system outside the exposure apparatus for the shape of a plurality of marks on the second object. 6) The alignment method described.

(10) The shapes of a plurality of marks on the second object are measured outside the exposure apparatus before and after resist coating, and the surface shapes are measured, and the relative positional relationship is measured in the exposure apparatus with the first object in the configuration. The alignment method according to the above (6), characterized in that an offset is used when it is aligned with a signal of an alignment detection system that performs relative alignment with the second object.

(11) In an exposure apparatus for transferring the pattern of the first object onto the second object in a relative position, a position detection system for detecting the positions of a plurality of marks on the second object outside the exposure apparatus. A three-dimensional shape measuring instrument for measuring the shapes of the plurality of marks is arranged, the second object is supported by a suction member, and the shapes of the plurality of marks on the second object are measured by the three-dimensional shape measuring instrument. And the three-dimensional relative position between the mark that can measure the three-dimensional position arranged on the suction member and the plurality of marks on the second object is measured by the position detection system and generated from the information. An offset is calculated, and the second object is moved to the exposure apparatus while being attracted to the suction member, and a detection system capable of measuring a three-dimensional position in the exposure apparatus is used to move the second object on the suction member. Measure only the mark The first object and the alignment of the second object, the exposure alignment apparatus characterized by.

(12) When exposing a plurality of second objects, the offset is measured for the first second object, and the same offset is used for the second and subsequent sheets. 11) The alignment device according to the above.

(13) The alignment apparatus according to (11), wherein the foreign matter inspection on the second object is also measured outside the exposure apparatus before and after the application of the photosensitive material for exposure.

(14) The offset generated at the time of measuring the focus of the second object is also measured outside the exposure apparatus after coating the photosensitive material for exposure, (11)
The alignment device described.

(15) The alignment apparatus according to (14), wherein the focus offset is obtained outside the exposure apparatus by a non-optical measurement system.

(16) The shape of the plurality of marks on the second object is outside the exposure apparatus, and the shape of the plurality of marks on the second object is measured by the three-dimensional shape measuring instrument before coating the photosensitive material for exposure. The alignment apparatus according to (11), wherein the shape of the plurality of marks on the second object is measured with the three-dimensional shape measuring device after the measurement and the photosensitive material is applied.

(17) Atomic force microscope (AF) is used to calibrate the shapes of a plurality of marks on the second object outside the exposure apparatus.
M: Atomic Force Microscope
The above (1) characterized in that the surface shape is measured by e).
6) The alignment device described.

(18) The surface shape is measured by a stylus-type three-dimensional shape measuring instrument when calibrating the shape of a plurality of marks on the second object outside the exposure apparatus.
The alignment device described.

(19) The surface shape is measured by the optical three-dimensional measurement calibrated by a non-light three-dimensional shape measuring system for the shape of a plurality of marks on the second object outside the exposure apparatus. 16) The alignment device according to the above.

(20) The shape of a plurality of marks on the second object is measured outside the exposure apparatus before and after resist coating, and the surface shape is measured and the relative positional relationship is measured in the exposure apparatus with the first object as the configuration. The alignment device according to (16) above, wherein an offset is used when the alignment is made so as to match the signal of the alignment detection system that performs relative alignment with the second object.

[0054]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to FIG.

First, the suction member for sucking the wafer will be referred to as a chuck here.

It has already been proposed to form an exposure system by arranging marks on the chuck (JP-A-2-126629).
Issue gazette).

This method will be described below.

In the system outside the exposure apparatus, the wafer already on the chuck is aligned by the interference system stage,
At that time, a mark (hereinafter referred to as a chuck mark) is also formed on the chuck, the position of the chuck mark is also measured, the relative positional relationship between the chuck mark and the wafer is obtained, and the chucked state is exposed as it is. This is a method in which the wafer is transported into the apparatus, alignment measurement is performed only on the chuck mark in the exposure apparatus, and exposure is performed based on the relative positional relationship between the chuck mark and the wafer obtained by the system outside the exposure apparatus.

FIG. 7 is a view showing a state in which chuck marks are arranged on the chuck and the wafer is sucked. A plurality of chuck marks (three in FIG. 7) are formed on the chuck, Cr or Cr oxide is formed on quartz glass like a mask or reticle 12 in lithography, and a part thereof is patterned to form Cr or the like. Is taken as an XY measurable mark.

Further, as already proposed by the applicant of the present invention, when a wafer is sucked by a pressure difference, a pressure plug is adopted at a side portion of the chuck so that the wafer can be moved while being sucked by the chuck. is doing.

This allows wafer handling for each chuck without using an air hose or the like.

As described above, in the system in which the wafer is handled after the marks are arranged on the chuck, alignment can be performed by various detection systems outside the exposure apparatus over time, and the alignment is performed by the chuck on the inside of the exposure apparatus. After the wafer is transferred as it is, it is possible to configure an exposure system that can perform contradictory performance such as high accuracy and high throughput, that is, exposure can be performed by measuring only chuck marks.

Therefore, in the present invention, the system using the chuck mark described above is used as an Offset Analyze.
We propose to introduce it into r and judge that this can solve the problems already explained.

FIG. 8 shows an embodiment of a configuration in which this function is provided.

The Offset Analyzer includes a chuck for supporting a wafer, which constitutes a pressure plug capable of moving while adsorbing a wafer, a chuck mark, an XYZ stage with an interferometer for three-dimensional movement, surface shape measurement with / without a resist. It is composed of a CPU, which has a simulator for controlling the entire Offset Offset Analyzer and a two-dimensional position detection system equivalent to the alignment scope configured in the exposure apparatus, and for calculating the alignment offset from the surface shape.

The actual wafer and information flow are shown in the already proposed Offset Analysis shown in FIG.
Although it is almost the same as r, the added point is that after measuring the alignment mark signal at each shot of the wafer after resist coating, two-dimensional measurement of the chuck mark is also performed based on the XYZ stage with an interferometer, and the wafer is placed in the exposure device. At the time of transfer, every chuck while holding the wafer on the chuck,
This is the point of transportation.

Next, referring to FIG. 9, in the exposure system of the present invention, Of
An example of an exposure apparatus will be described in which, after all the measurements are completed by the fset Analyzer, the wafer is conveyed chuck by chuck while chucking the wafer, and only the chuck marks are measured to perform exposure.

The chuck conveyed while sucking the wafer is sucked by the chuck sucking the chuck of the exposure apparatus. The focus detection system detects the focus of the chuck mark and, if necessary, drives in the focus direction, and then the alignment detection system AS measures the position of the two-dimensionally measurable mark on the chuck mark. This measurement is performed for multiple chuck marks and Offset
Each shot is driven by the XY stage 18 with an interferometer on the basis of the measurement and calculation results in the Analyzer, focus measurement is performed in each shot, and after driving in the focus direction as necessary, exposure is performed, and after all shot exposure,
The chuck is conveyed to the outside of the exposure apparatus while the wafer is adsorbed.

In FIG. 9, a TTL-Off using a non-exposure light source 5 such as a HeNe Laser or a semiconductor laser, which has a stable baseline and is inexpensive and stable.
The axis system is adopted as the alignment detection system AS for two-dimensional detection of the chuck mark. At this time, since the alignment detection system AS of the exposure apparatus only measures the chuck marks, it does not require a complicated configuration and does not require TIS removal, which can lead to a significant cost reduction.

TIS is an Offset Analyzer
It is only necessary to use the above detection system, and the signal simulator does not need to consider TIS.

(Other Embodiments) Even if the present invention is applied to focus detection and foreign matter inspection, the cost of the entire exposure system can be similarly reduced.

This is not the case where only the plane (XY) measurement is performed, but if the focus (Z) is similarly measured by a system outside the exposure apparatus, the exposure apparatus only needs to measure XYZ only the chuck mark. Is.

Further, the wafer handling O after the mark is arranged on the chuck of the present invention outside the exposure apparatus.
Items that affect the throughput of the exposure system, such as configuring a non-optical measurement system such as a capacitance sensor or an air sensor in the ffset Analyzer to calculate the focus offset, and performing a foreign matter inspection including the peripheral portion of the wafer. It is also possible to build a system that performs the exposure outside the exposure apparatus as much as possible. An example of this configuration is shown in FIG. The Offset Analyzer includes a chuck that supports a wafer having a pressure plug that is movable while adsorbing the wafer, an XYZ stage that moves the wafer in three dimensions,
Profile to measure surface profile with / without resist
er, a two-dimensional position detection system equivalent to an alignment scope configured in the exposure apparatus, a focus detection system, a foreign matter inspection system capable of performing a foreign matter inspection including the peripheral portion of the wafer, Off
It is composed of a CPU that has a simulator that controls the entire set analyzer and calculates an alignment offset from the surface shape.

However, the detection principle of each detection system has already been proposed and implemented in various places and the effect thereof has been confirmed, and any method may be adopted, so the description thereof will be omitted here.

The actual wafer and information flow is shown in FIG.

Before applying the resist as shown in FIG. 11-, the wafer is offset (not adsorbed on the movable chuck on which the chuck mark is placed here) Offset Anal.
It is transported to the yzer.

Next, as shown in FIG. 11-, the three-dimensional shape of the alignment mark on this wafer is measured by the Profiler.

Next, as shown in FIG. 11-, the wafer is carried to a coater to apply a resist, and the resist is applied.

Next, as shown in FIG. 11-, the wafer is again carried to the Offset Analyzer, but at this time, it is adsorbed by the movable chuck on which the chuck mark is mounted and is conveyed with each chuck, and the resist on the alignment mark is transferred. The surface shape is measured by Profiler.

Therefore, the Offset Analyzer
In this case, it is necessary to have a function that can be mounted on only a wafer or a chuck with a chuck mark.

This may be achieved by one mechanical mechanism, or a wafer before resist coating may be a movable chuck with chuck marks on it or a chuck having no chuck marks for the purpose of profiler measurement. It is also possible to suck the wafer once, measure the profiler, and then separate the wafer from the chuck and carry the wafer to the coater for resist coating.

It is possible that the resist coating can be kept adsorbed on the chuck, but since the chuck marks and the chuck are also covered with the resist, cleaning is required and this cannot be said to be a good measure.

At the same time as measuring the surface shape of the resist on the alignment mark with the Profiler, or before and after the measurement, the alignment detection system configured in the Offset Analyzer detects the X and Y directions arranged in each shot on the wafer. Alignment signals of a plurality of alignment marks for detecting are detected. At this time, focus measurement is also performed to obtain the three-dimensional positional relationship of each shot.

Next, three-dimensional position measurement of a plurality of chuck marks is performed with reference to an XYZ stage with an interferometer.

The already proposed Offset Analysis
As described in er, the offset amount generated by the signal simulator is calculated.

The foreign matter inspection can be carried out before the resist is applied to prevent the foreign matter from diffusing into the coater, or after the application, it is possible to carry out a sequence for preventing the occurrence of defective exposure.

When all the measurements are completed in the Offset Analyzer, the wafer is transferred to the exposure apparatus with the chuck held on the chuck, together with the three-dimensional relative relationship information between the wafer and the chuck mark.

Based on this three-dimensional relative relationship between the offset and the chuck mark, the exposure apparatus measures the three-dimensional position of only the chuck mark to perform mark alignment and exposure. After exposure of all shots, the wafer is Delivered to developer for development.

The structure of the exposure apparatus is the same as that of the embodiment shown in FIG. 9, and the chuck conveyed while sucking the wafer is
The chuck of the exposure apparatus attracts the chuck.
The focus detection system detects focus only on the chuck mark, and after driving in the focus direction as needed, the position of the two-dimensionally measurable mark on the chuck mark is measured by the alignment detection system AS. This measurement is performed for a plurality of chuck marks, and Offset Ana
Based on the measurement and calculation results of the lyzer, each shot is driven by the XY stage 18 with an interferometer, and focus measurement is unnecessary for each shot this time, so it is Off
The exposure is performed after driving in the focus direction as necessary based on the measurement information in the t Analyzer, and after all shot exposure, the chuck is conveyed to the outside of the exposure apparatus while the wafer is adsorbed.

As a result, in the exposure apparatus, only the chuck marks are three-dimensionally measured, and then the exposure is performed. Therefore, the throughput of the exposure apparatus can be improved.
Coo ( C of the whole exposure system including etAnalyzer
the ost O f O wnership) performance of the that you Up.

Further, regarding the focus, in order to eliminate the influence on the exposure pattern surface, the XY stage 18 is driven to obtain the amount of offset generated by the pattern, or a focus system using non-light is constructed to perform the offset. Off
It is also possible to obtain it on the set Analyzer.
At this time as well, Off within a range that does not hinder the exposure in the exposure apparatus.
Similarly, various things can be performed in the set Analyzer without lowering the throughput.

Also, the Offset An of wafer handling after the mark is arranged on the chuck of the present invention.
The method of using the aligner is not limited to the TTL Offaxis method in the exposure apparatus as shown in FIG. For example, even when the chuck mark position is detected using an Offaxis microscope, it is possible to prevent the accuracy deterioration due to the asymmetric alignment mark shape due to the process.

As a matter of course, measures against the baseline fluctuation are necessary in the Offaxis microscope, and it is necessary to use a member that is not easily affected by heat and to frequently perform baseline correction.

As described above, the offset of the wafer handling after the mark is arranged on the chuck of the present invention.
The method using the Analyzer prevents the accuracy deterioration due to the asymmetry of the alignment mark shape due to the process, and thus enables a highly accurate and high-throughput alignment method without being affected by the semiconductor forming process such as CMP. Therefore, complicated optimization in the process is unnecessary, and Coo can be improved.

In the description of the present invention, the exposure apparatus has been described as an exposure apparatus for exposing a circuit pattern.
As mentioned at the beginning, it is used for convenience, so-called steppers, scanners, X-ray exposure of equal magnification, EB direct drawing, EUV etc. Needless to say, it is effective.

As a matter of course, it is premised that the signal of the alignment detection system included in the exposure system of the exposure system can be calculated by signal simulation from the alignment mark and the resist shape information if they are known.

[0097]

According to the present invention, even if there is asymmetry in the alignment mark of the wafer, its shape is measured in advance outside the exposure apparatus and the generated offset is calculated,
In addition, by measuring the wafer and the chuck mark, and exposing the wafer by measuring only the chuck mark in the exposure device, the problem of reduction in throughput does not occur and it is stable without being affected by various processes. In addition, it is possible to perform highly accurate wafer alignment without increasing the cost of the device.

[Brief description of drawings]

FIG. 1 is a diagram showing an example in which a rotation error occurs in an alignment error.

FIG. 2 is a diagram showing an example in which a magnification error occurs as an alignment error.

FIG. 3 is a diagram showing data measured by an AFM on an actual alignment mark.

FIG. 4 is a diagram showing a structure of an alignment mark called metal CMP.

FIG. 5 is a conceptual diagram showing a wafer and a flow of information in the Offset Analyzer.

FIG. 6 is a diagram showing a configuration of an Offset Analyzer.

FIG. 7 is a schematic view of an embodiment in which a system for carrying out wafer handling after arranging chuck marks on the chuck outside the exposure apparatus is configured.

FIG. 8 is a diagram showing an embodiment of an OffsetAnalyzer using a chuck mark newly proposed in the present invention.

FIG. 9 is a diagram showing an example of an exposure apparatus when a chuck mark newly proposed in the present invention is detected on the exposure apparatus.

FIG. 10 is a diagram showing an embodiment in the case where a focus detection system and a foreign matter inspection system are also configured in an Offset Analyzer using a chuck mark newly proposed in the present invention.

FIG. 11: Offset A newly proposed by the present invention
Conceptual diagram showing wafer and information flow in analyzer

[Explanation of reference numerals] 1 wafer 5 light source (for example, He-Ne laser) 7 fiber 8 alignment illumination optical system 9 beam splitter 10 relay lens 11 objective 12 reticle 13 reduction projection optical system 14 mirror 15 erector 16 CCD camera 17 on CCD camera Formed chuck mark image 18 XY stage 20 Illumination optical system for reticle pattern exposure 21 Movable wafer chuck with chuck mark 22 θ-Z stage 23 Tilt stage 25 Bar mirror 26 Laser interferometer 29 Focus measurement system (projection system) 30 Focus measurement system (detection system) AS TTL O
ffaxis alignment scope 31, 32 chuck mark 33 chuck for chuck chuck 51 computer

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01L 21/30 525W 525X (72) Inventor Takahiro Matsumoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. In-house F-term (reference) 2F069 AA03 AA66 BB15 GG01 GG07 GG52 HH30 5F046 ED02 FC04 FC05

Claims (20)

[Claims] 1. An exposure apparatus for transferring a pattern of a first object onto a second object in relative alignment, and a position detection system for detecting the positions of a plurality of marks on the second object outside the exposure apparatus. A three-dimensional shape measuring instrument for measuring the shapes of a plurality of marks is arranged, and the second object is supported by a suction member,
A mark capable of measuring the shape of the plurality of marks on the second object with the three-dimensional shape measuring device and measuring the three-dimensional position arranged on the suction member; and a plurality of marks on the second object. Of the three-dimensional relative position of the second object is measured by the position detection system, an offset generated from the information is calculated, and the second object is moved to the exposure device while being attracted to the attraction member, and the exposure is performed. A position characterized in that only a mark on the suction member is measured by a detection system capable of measuring a three-dimensional position in the apparatus, the first object and the second object are aligned, and exposure is performed. How to match. 2. When exposing a plurality of second objects, the offset is measured for the first second object, and the same offset is used for the second and subsequent sheets. The described alignment method. 3. The alignment method according to claim 1, wherein the foreign matter inspection on the second object is also measured outside the exposure apparatus before and after coating the photosensitive material for exposure. 4. The alignment method according to claim 1, wherein the offset generated when measuring the focus of the second object is also measured outside the exposure apparatus after coating the photosensitive material for exposure. 5. The alignment method according to claim 4, wherein the focus offset is obtained outside the exposure apparatus by a non-optical measurement system. 6. The shape of the plurality of marks on the second object is measured outside the exposure device by the three-dimensional shape measuring instrument before the application of the photosensitive material for the exposure, before measuring the shape of the plurality of marks on the second object. The alignment method according to claim 1, wherein the shapes of the plurality of marks on the second object are measured by the three-dimensional shape measuring instrument even after the photosensitive material is applied. 7. Atomic force microscope (AFM: A) when calibrating the shape of a plurality of marks on a second object outside the exposure apparatus.
The alignment method according to claim 6, wherein the surface shape is measured by using a tomic force microscope. 8. The alignment method according to claim 6, wherein the surface shape is measured by a stylus type three-dimensional shape measuring instrument during calibration of the shape of the plurality of marks on the second object outside the exposure apparatus. 9. The surface shape is measured by optical three-dimensional measurement in which the shape of a plurality of marks on the second object is outside the exposure apparatus and calibrated by a non-light three-dimensional shape measuring system. The described alignment method. 10. The shape of a plurality of marks on a second object is measured outside the exposure apparatus before and after resist coating to measure the surface shape, and the relative positional relationship is measured in the exposure apparatus in the constitution of the first object and the above. 7. The alignment method according to claim 6, wherein an offset is used when it is aligned with a signal of a alignment detection system that performs relative alignment with the second object. 11. An exposure apparatus for transferring a pattern of a first object onto a second object in a relative position, and a position detection system for detecting the positions of a plurality of marks on the second object outside the exposure apparatus. A three-dimensional shape measuring instrument for measuring the shapes of a plurality of marks is arranged, the second object is supported by a suction member, and the shapes of the plurality of marks on the second object are measured by the three-dimensional shape measuring instrument. And an offset generated from the information by measuring the three-dimensional relative position of the mark arranged on the suction member and capable of measuring the three-dimensional position and a plurality of marks on the second object by the position detection system. Is calculated by calculation, the second object is moved to the exposure device while being attracted to the suction member, and the mark on the suction member is detected by a detection system capable of measuring a three-dimensional position in the exposure device. Only measured and said An aligning device, which aligns a first object and the second object and exposes them. 12. The method according to claim 11, wherein when a plurality of second objects are exposed, the offset is measured for the first second object and the same offset is used for the second and subsequent sheets. The alignment device described. 13. The alignment apparatus according to claim 11, wherein the foreign matter inspection on the second object is also measured outside the exposure apparatus before and after applying a photosensitive material for exposure. 14. The alignment apparatus according to claim 11, wherein the offset generated when measuring the focus of the second object is also measured outside the exposure apparatus after applying the photosensitive material for exposure. 15. The method according to claim 1, wherein the focus offset is obtained outside the exposure apparatus by a non-optical measurement system.
4. The alignment device according to 4. 16. The shape of the plurality of marks on the second object is measured outside the exposure device by the three-dimensional shape measuring instrument before the application of the photosensitive material for the exposure, before measuring the shape of the plurality of marks on the second object. The alignment apparatus according to claim 11, wherein the shapes of the plurality of marks on the second object are measured by the three-dimensional shape measuring instrument even after the photosensitive material is applied. 17. An atomic force microscope (AFM: AFM) when calibrating the shapes of a plurality of marks on a second object outside the exposure apparatus.
The alignment apparatus according to claim 16, wherein the surface shape is measured by Atomic Force Microscope. 18. The alignment apparatus according to claim 16, wherein the surface shape is measured by a stylus type three-dimensional shape measuring instrument during calibration of the shape of the plurality of marks on the second object outside the exposure apparatus. 19. The surface shape is measured by optical three-dimensional measurement calibrated by a non-light three-dimensional shape measuring system outside the exposure apparatus for the shape of a plurality of marks on the second object. The alignment device described. 20. The shape of a plurality of marks on a second object is measured outside the exposure apparatus before and after resist coating to measure the surface shape, and the relative positional relationship is measured in the exposure apparatus by the configuration of the first object and the above. 17. The alignment device according to claim 16, wherein an offset is used for alignment so as to match a signal of a alignment detection system that performs relative alignment with the second object.