JP2797506B2 - Exposure equipment - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to an improvement of an exposure apparatus used in a photolithography method (photolithography method), and more particularly, to an improvement in an existing pattern previously formed on a substrate. The present invention relates to a laser exposure apparatus suitable for precisely forming a drawing pattern by overlapping later.

(Prior Art) Conventionally, an exposure apparatus used for a photolithography method is known. In this exposure apparatus, for example, as one method of forming a thin film transistor (TFT), as shown in FIG. 13, a chromium-Cr thin film 2 is formed on a glass plate 1 as a clean and cleaned substrate, and then, A photosensitive positive resist film 3 is formed on the thin film 2, a mask pattern (not shown) is adhered to the glass plate 1, the resist film 3 is exposed through the mask pattern, and the resist film is developed by development. The exposed portion 4 of No. 3 is removed, and the unexposed portion 5 is left. Next, the chromium thin film portion 6 from which the resist film 3 has been removed by etching is dissolved, the unexposed portion 5 is removed, and a chrome gate electrode 7 is first formed on the glass plate 1. Then, a thin film 8 of insulating silicon nitride SiNx is formed on the existing pattern of the chrome gate electrode 7. Then, a positive resist film 9 is formed on the thin film 8, then a mask pattern corresponding to the insulating silicon nitride film is brought into close contact, and the resist film 9 is exposed through the mask pattern. In this case, the alignment with the existing chromium gate electrode pattern is performed using an alignment pattern (alignment mark) commonly formed around each mask around the mask.

Then, the exposed portion 10 of the resist film 9 is removed by development, the silicon nitride thin film portion from which the resist film 9 has been removed by etching is dissolved, and the unexposed portion 11 is removed. Thus, a silicon nitride insulating film 12 having a predetermined pattern and a predetermined positional relationship is formed.

Such a process is repeated to form a thin film transistor, but what should be noted is the positional relationship between the constituent layers, and it is usually necessary to adjust the position within several μm.

(Problems to be Solved by the Invention) By the way, this kind of thin film transistor is manufactured in a clean room, and the room temperature of the clean room is usually controlled within a range of ± 1 ° C. When subsequently forming a drawing pattern on the formed existing pattern, if a large area (for example, a substrate having a length of 600 mm and a width of 800 mm) is to be manufactured, a change in temperature of ± 1 ° C. will be several tens of dimensions. Therefore, in an exposure apparatus that exposes a mask pattern in close contact with a substrate, the positional relationship between a drawing pattern formed later on an existing pattern formed on the substrate and a pattern formed later is, for example, a part. Even if it is according to the design data planned in advance, when viewed over the whole area of the board, it does not meet the design value planned in advance and a deviation occurs There has been a problem to say.

Further, even if the room temperature of the clean room is strictly controlled at a constant temperature, the glass substrate is often heated in the film formation process of each layer, but when the heating temperature is higher than a certain level, the glass substrate is generally heated. It shrinks, and the degree of the shrinkage may not be uniform. For this reason, there is also a problem that the positional relationship between a drawing pattern formed later with respect to an existing pattern formed earlier on the substrate cannot be obtained as designed in advance.

Further, as a completely different problem, a defect inspection problem arises when an attempt is made to manufacture a device having a large area and a large number of pixels. That is, the manufacturing process of the thin film transistor is complicated, and the rate of occurrence of various defects is high. In fact, the shrinkage of the thin film transistor array is low. However, when used in a liquid crystal display or the like, it is required to be almost defect-free. At least each time each layer of the thin film transistor is patterned, a defect inspection of the pattern shape is performed, and if a defective portion is repaired, the yield is increased, and the waste of flowing the defective product to the subsequent process can be avoided. Therefore, the inspection of the entire shape of all the parts is useful, but the time required therefor leads to a considerable increase in cost.

The present invention has been made in view of the above circumstances, and a main object thereof is a design in which a positional relationship between a drawing pattern formed later and an existing pattern formed earlier on a substrate is previously planned. An object of the present invention is to provide an exposure apparatus which can be obtained over the entire area of a substrate at a value and can easily manufacture a large-area apparatus easily and precisely. Another object of the present invention is to perform the shape inspection step at the lowest possible cost.

(Means for Solving the Problems) The features of the exposure apparatus according to the present invention are based on a laser exposure apparatus, and a reading optical system for optically reading an existing pattern previously formed on a substrate as actual existing pattern data; A processing laser irradiation optical system that irradiates the substrate with a processing laser beam to form a drawing pattern on the existing pattern later; and an existing pattern design data corresponding to the existing pattern and a drawing pattern corresponding to the drawing pattern. A comparing unit having a memory for storing design data and comparing the actual existing pattern data with the existing pattern design data and having a misalignment inspection and a shape defect inspection function; and the actual existing pattern for the existing pattern design data. The processing laser is modified based on the amount of data deviation by modifying the drawing pattern design data. And a control unit for controlling at least the irradiation optical system.

(Operation) According to the exposure apparatus of the present invention, the existing pattern previously formed on the substrate is read by the reading optical system as actual existing pattern data. The comparing unit compares the actual existing pattern data with the existing pattern design data stored in the memory, instructs a position or the like if there is a shape defect, and draws based on the comparison result if there is a positional deviation. Modify the pattern design data and control the processing laser irradiation optical system.

(Example) Hereinafter, an example of an exposure apparatus according to the present invention will be described with reference to the drawings.

1 to 4 show a first embodiment of the exposure apparatus according to the present invention. In FIG. 1, reference numeral 20 denotes an X table. On this X table 20, a glass plate 1 as a substrate is placed. This glass plate 1 is an X table
Positioning is set at 20 predetermined positions.

A chrome gate electrode 7 as a ready-made pattern is formed on the glass plate 1 as shown in FIGS. 1 and 2, and a thin film 8 of silicon nitride SiNx is formed on the gate electrode 7.
On the silicon nitride SiNx thin film 8, a resist film 9 is formed. In addition, positioning marks 24, 24 for determining the relative position of the chrome gate electrode 7 in the X and Y directions with respect to the glass plate 1 are formed on the glass plate 1 as shown in FIG. FIGS. 1 to 3 schematically show the number and intervals of the chrome gate electrodes 7 formed on the glass plate 1, although they are different from each other. It is understood that they have the same shape and the same interval. I want to be.

The X table 20 is driven by an X table
It is driven back and forth in the -X 'direction. The X table drive
25 is controlled by the output information from the comparison / operation control circuit unit 26. An exposure optical system is provided above the X table 20. The exposure optical system includes a reading optical system 27 and a processing laser irradiation optical system. The reading optical system 27 plays a role of optically reading an existing pattern previously formed on the substrate as actual existing pattern data, and includes a reading laser light source 29 and an oblique half mirror 3.
0, cylindrical lens 29 ', polygon mirror 31, F
θ lens 30 ', total reflection mirror 32, cylindrical lens
33 and a detector 34. The processing laser irradiation optical system 28 plays a role of irradiating the substrate with processing laser light in order to form a drawing pattern on the existing pattern later, and forms a processing laser light source 35, a cylindrical lens 35 ', a polygon mirror 31', Fθ It is roughly composed of a lens 32 ', a total reflection mirror 28', and a cylindrical lens 33 '. The symbol O ₁ is for the processing laser irradiation optical system 28.
Reference numeral O ₂ denotes an optical axis of an irradiation system of the reading optical system 27, and reference numeral O ₃ denotes an optical axis of a reflection system of the reading optical system 27. The optical axis O ₃ of the reflector system is inclined with respect to the optical axis O ₂ of the illumination system. This is the optical axis of the reflection system with respect to the glass plate 1.
This is because when O ₃ is perpendicular, the amount of reflected light received by the detector 34 becomes extremely large when the reflected light is perpendicular to the glass plate 1. The processing laser light emitted from the processing laser light source 35 has a property of exposing the resist film 9, and the laser light emitted from the reading laser light source 29 has a property of not exposing the resist film 9. The light and the wavelength of the reading laser light are different.

The comparison / arithmetic control circuit unit 26 corresponds to a memory 37 for storing an existing pattern design data corresponding to the chromium gate electrode pattern as an existing pattern and a silicon nitride film pattern as a drawing pattern to be formed later on the existing pattern. Memory 38 for storing drawing pattern design data
While information is exchanged between the device and the device, the read output from the detector 34 is input as data. As the existing pattern design data, for example, the distance in the X direction from the positioning mark 24 to each chrome gate electrode 7 is used. Also,
As the drawing pattern design data, for example, data of a positional relationship to be formed with respect to the existing pattern design data is used. The comparison unit of the comparison / arithmetic control circuit unit 26 compares the signal from the detector 34 with the existing pattern design data, performs a shape defect inspection, and displays a defect position.

The comparison / arithmetic control circuit 26 has a function of controlling at least the polygon mirror driving devices 36 and 36 'for driving the polygon mirror 31, the X-table driving device 25, and the processing laser light source 35. Are supplied with the rotational position reference signals from the polygon mirror driving devices 36 and 36 '.
Rotating the polygon mirror 31, a chromium gate electrode 7 is operated in advance with the laser beam P ₁ read laser optical system 27 as shown in Figure 2. This laser light P ₁
, The distance (position) in the X direction from the alignment mark 24 on the front side in the X direction to the chrome gate electrode 7 is detected. This is achieved, for example, by using a position sensor for the detector 34. That is, based on the time when the X table 20 is at a predetermined position, the alignment mark 24 on the front side in the X direction is the laser beam P _1.
Scanning using a laser beam P ₁ of the glass plate 1 in order to know in which position in the Y direction scanning. This laser light P ₁
In the scanning, the laser beam P ₁ crosses the area where the alignment mark 24, the amount of light reflected from that portion is increased for example. The laser beam P ₁ of the reflected light is received by the detector 34. If the reflected light forms an image at a position shifted vertically and horizontally from the center position of the detector 34, output information regarding the shifted position is input to the arithmetic and control circuit 26. Therefore, the arithmetic control circuit unit 26 determines that the alignment mark 24 on the front side in the X direction is
It is possible to know at which position in the X and Y directions the detection has been made.

Then, the comparison / operation control circuit unit 26 stores the X table 20 in the X
Drive a predetermined amount in the direction. Accordingly, the scanning position by the laser beam P ₁ of on the glass plate 1 is changed. At a portion where the chrome gate electrode 7 is not formed, the output information cannot be obtained from the detector 34 due to, for example, a low reflectance.
Then, the laser beam P ₁ is applied to the first chrome gate electrode 7.
When scanning is performed above, the light enters the detector 34. This detector
The position in the X direction from the alignment mark 24 to the first chrome gate electrode 7 is obtained by 34. Similarly Y
With respect to the direction, position data is obtained at predetermined intervals.

The position data (X position, Y position) from the alignment mark 24 to the chrome gate electrode 7 thus obtained is used as the actual existing pattern data, and the actual read actual existing pattern data and the data stored in the memory 37 are stored. Compare the existing pattern design data with the existing pattern design data, calculate the amount of deviation of the actual existing pattern data from the existing pattern design data,
The processing laser irradiation optical system 28 is controlled by modifying the drawing pattern design data.

For example, as shown in FIG. 4, if originally the away distance X ₁ from the alignment mark 24 in the X direction 1
If there is a chrome gate electrode 7 (shown by a solid line), its X
When the direction of width X _3, data relating to the distance X _1, the width X ₃ is stored in the memory 37 as the existing pattern design data. Further, if it is planned to form the silicon nitride molded film 12 (see the two-dot chain line) with a width of X ₂ + X ₃ + X ₄ with respect to the chrome gate electrode 7, X ₁ −X ₂ , X ₁ + X ₃ + X ₄ is stored in the memory 38. However, the fact the distance to the first chromium gate electrode 7 formed on the glass plate 1 was X _5. Then, this information is sent to the comparison / operation control circuit unit 26 by the detector 34.
It is input to the comparison and calculation control circuit 26 obtains the difference between the X ₅ -X _1, modifies the drawing pattern design data on the basis of this difference, the processing laser light source 36 based on this correction data is controlled.

In this description, the data in the Y direction is fixed, but the data in the Y direction is also obtained at predetermined intervals.

In this manner, the processing after the laser irradiation using an optical system 28 desired drawing pattern is obtained by exposure to be formed, as in the related art that the processing laser light P ₂ has been positive resist film 9 exposed by The exposed portion is removed by development, and the silicon nitride SiNx in the portion where the resist film 9 has been removed by etching is dissolved to form a desired drawing pattern.

This makes it possible to obtain a positional relationship between a drawing pattern formed later with respect to an existing pattern formed earlier on the substrate over the entire area of the substrate as designed in advance and to obtain a large area. It can be manufactured easily and precisely.

Figure 5 is shows an example of forming overlapping later drawing pattern other shapes existing patterns of different other shapes from the first embodiment, first, prior to the laser beam P ₁ for reading
Is used to detect the position from the alignment mark (not shown) in the X direction to the existing pattern 40 to obtain the actual existing pattern data. This is compared with the existing pattern design data stored in the memory 37. Next, the shift amount of the actual existing pattern data with respect to the existing pattern design data is calculated, and the drawing pattern design data is corrected. Then, the processing laser light source 35 is controlled based on the correction data. Thus, the laser beam P ₂ for processing is irradiated onto the resist film 9 of the glass plate 1, a resist film 9 is exposed. Here, the laser beam P ₂ spots 41
It is particularly desirable to irradiate the laser light in a superimposed manner as shown in FIG. 6 in order to prevent the portion to be exposed from being unexposed when the laser is pulsed. In FIG. 5, reference numeral 42 denotes a drawing pattern which is formed by being superimposed on the existing pattern 40 later.

FIGS. 7 to 12 show a second embodiment of the exposure apparatus according to the present invention, in which a CCD camera is used as a detector. The optical system 27 is roughly composed of an illumination light source 50, a light projecting lens 51, half mirrors 52 and 53, an objective lens 33, a focusing lens 54, and a detector 34, and the processing laser irradiation optical system 28 includes a processing laser light source 35, It is roughly composed of a condenser lens 55, a galvanometer mirror 56, a galvanometer mirror driving device 56 ', and a half mirror 53.

In the exposure apparatus of the second embodiment, the glass plate 1 is positioned and set on an XY table 20 ', and the XY table 20'
It is driven in the X and Y directions by a table driving device 25 '. Further, the processing laser beam P ₂ is scanned in the XY direction by the galvanometer mirror 56. Here, it is used as the detector 34
The CCD camera is capable of photographing a small area S of the glass plate 1 as shown in FIGS. The boundary between the small areas slightly overlaps with the boundary between adjacent small areas. With this CCD camera, existing pattern data is obtained for each small area S.

For example, in FIG. 8, the hatched portion indicates the actual existing pattern 60. On the other hand, reference numeral 61 denotes an original existing pattern formed in the small area S based on the existing pattern design data. Also, in FIG.
Indicates a portion to be exposed to the original existing pattern by the processing laser beam.

The comparison / arithmetic control circuit unit 26 compares the actual existing pattern data of the small area S with the existing pattern design data corresponding to the small area S and compares the shift amounts. Then, the drawing pattern design data is corrected based on the shift amount.
That is, as shown in FIG. 8, when the actual existing pattern 60 is displaced from the original existing pattern 61, the drawing pattern design data is corrected so that the processing laser light is irradiated correspondingly. .

Then, the comparison / operation control circuit unit 26 controls the processing laser light source 35 and the galvanomirror 56 based on the corrected drawing pattern design data. That is, processing laser light
P ₂ is scanned in the Y direction as shown in FIG. 9 by the galvanomirror 56, sequentially scanning position in the X-direction is changed. In this manner, the resist film 9 is exposed so that a drawing pattern is formed so as to be overlaid on the actual existing pattern of the first small section S later. FIG. 8 shows a portion 63 to be actually exposed.

Then, when the exposure of the first small section S is completed, the comparison / operation control circuit section 26 drives the XY table 20 'in the X direction so that the second small section S enters the field of view of the CCD camera. I do. Then, the resist film 9 is exposed in the same manner as in the first small area. When the exposure of the second small section S is completed, the XY table 20 'is similarly moved in the X direction, and when the exposure of the third small section S is completed, the comparison / comparison is performed.
The arithmetic control circuit 26 drives the XY table 20 'in the Y direction,
The fourth small area S is set in the field of view of the CCD camera. In this manner, the entire area of the glass plate 1 is exposed to form a drawing pattern.

Hereinafter, an example of use of the exposure apparatus according to the present invention will be described.

The new layer to be patterned is aluminum
In the case of an opaque layer made of Al, chromium Cr, or another substance, it cannot be performed by the same method using the exposure apparatus described in the first and second embodiments. In this case, a known lift-off method can be used. That is, before a layer (opaque layer) for forming a new pattern is formed, the resist pattern is formed on the existing pattern of the resist film and exposed according to the method described in the first and second embodiments to form a resist pattern. However, this time, the resist in the pattern portion to be newly formed is dissolved and disappears. And
After exposure and development, a layer to be newly formed was formed.
Then, when the resist pattern was dissolved, a new pattern film on the resist was also peeled off, and a necessary pattern portion could be formed in a portion without the resist layer.

If the layer to be newly formed is opaque or the layers underneath overlap one another and it becomes difficult to read the position, the position is read from the back surface of the substrate and the first layer (first layer) is read. No problem occurred even if the pattern was read and used as existing position data.

When the existing pattern to be detected as the position data was transparent and the position could not be detected, the existing pattern below it could be read and used as the existing position data.

Since it takes time to read all the existing patterns to obtain position data, exposure was performed by detecting the position of the representative point, but no problem occurred. An appropriate point in the pattern can be selected as the representative point, but a number of alignment marks provided on the periphery of the substrate can also be used. When a mask was formed so that a thin film was not formed on the portion where the alignment mark was formed, exposure could be performed with sufficient positional accuracy in most cases for patterning the opaque layer.

By comparing the position reading signal with the design pattern in detail, it was possible to detect a defect in the existing pattern. Therefore, if the exposure apparatus according to the present invention is used, the defect inspection can be performed at the same time, and the efficiency is improved. Also,
It is possible to save waste and trouble of processing defective products.

In summary, the technical idea of the exposure apparatus according to the present invention is that, when a pattern of a plurality of layers is formed on one substrate, an existing device previously formed on the substrate is prevented in order to prevent misalignment of each layer due to various causes. The position of the pattern is read, and at least the processing laser is controlled by modifying the drawing pattern design data of the drawing pattern formed on the existing pattern based on the read information. Various embodiments can be considered without impairing them. For example, although the manufacture of a thin film transistor has been described as an example, the present invention can be applied to a semiconductor device printed circuit board requiring other laminated patterns.

(Effect of the Invention) As described above, the exposure apparatus according to the present invention reads the actual existing pattern data of the previously formed existing pattern, and reads the original drawing pattern based on the actual existing pattern data and the original existing pattern data. With the modification, the positional relationship between the drawing pattern formed later with respect to the existing pattern formed earlier on the substrate can be obtained over the entire area of the substrate as designed in advance, and the shape can be obtained. Since defect inspection can also be performed, there is an effect that large-area products can be easily and precisely manufactured at high yield and at low cost.

[Brief description of the drawings]

1 to 4 are views showing a first embodiment of an exposure apparatus according to the present invention. FIG. 1 is an optical diagram showing a schematic configuration of the exposure apparatus according to the present invention, and FIG. FIG. 3 is a perspective view for explaining the state of exposure of the apparatus to the substrate, FIG. 3 is a plan view of the glass plate shown in FIG. 1, and FIG. 4 is an explanatory view used to explain the operation of the exposure apparatus shown in FIG. FIG. 5 is an explanatory view in the case of forming different drawing patterns on different existing patterns, FIG. 6 is a view showing the overlap of spots of the processing laser light, and FIGS. 7 to 12 are views of an exposure apparatus according to the present invention. FIG. 7 is a view showing a second embodiment, FIG. 7 is a view showing a schematic configuration of an exposure apparatus, FIG. 8 is an explanatory view in a case where an existing pattern and a drawing pattern are manufactured by the exposure apparatus, FIG. FIG. 12 is an explanatory view of forming a drawing pattern for each small area, and FIG. 13 is a thin film. FIG. 4 is a cross-sectional view illustrating an example of formation of a transistor. 1 glass plate 7 chrome gate electrode 9 resist film 27 reading optical system 28 processing laser irradiation optical system 26 comparison / operation control circuit unit (control unit) 31 polygon mirror 37 38 …… Memory

Continuation of the front page (56) References JP-A-60-62122 (JP, A) JP-A-59-222838 (JP, A) JP-A-63-289815 (JP, A) JP-A-61-84833 (JP, A) , A) JP-A-62-66257 (JP, A) JP-A-2-204746 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01L 21/027

Claims (3)

(57) [Claims] 1. A reading optical system for optically reading an existing pattern previously formed on a substrate as actual existing pattern data, and a processing laser beam on the substrate to form a drawing pattern on the existing pattern later. A processing laser irradiation optical system that irradiates the existing pattern design data corresponding to the existing pattern and a drawing pattern design data corresponding to the drawing pattern, and the actual existing pattern data and the existing pattern design A comparison unit that compares data with the existing pattern design data, and a control unit that controls the processing laser irradiation position by modifying the drawing pattern design data based on a shift amount of the actual existing pattern data with respect to the existing pattern design data. An exposure apparatus, comprising: 2. The exposure apparatus according to claim 1, wherein the reading optical system includes a CCD camera that reads an existing pattern formed on the substrate. 3. The exposure apparatus according to claim 1, wherein the comparing unit has a function of inspecting a shape defect of an existing pattern.