JP2577339B2 - Inspection method of resist pattern on substrate by electron beam exposure apparatus - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an inspection method when a resist pattern is formed on a substrate by a raster scan type electron beam exposure apparatus.

(Prior Art) In order to form a pattern by an electron beam exposure apparatus, the following method is employed. First, a voltage is applied to the deflection electrode of the apparatus, and the electron beam is scanned by a certain distance, and at the same time, a stage on which a substrate previously coated with a resist film is mounted is moved in a direction perpendicular to the beam scanning. Then, the movement of the stage is repeated in a forward direction and a reverse direction, and a desired area of the substrate is scanned with an electron beam to form a pattern.

Conventionally, as a method of inspecting (forming) such a resist pattern, a method disclosed in Japanese Patent Application Laid-Open No. 56-30723 is known.

The conventional method for inspecting a resist pattern includes, for example, a step of mounting and fixing a glass substrate to which an electron beam resist film is applied, on a drive stage of an electron beam exposure apparatus,
At least one auxiliary pattern is scanned by an electron beam from the electron beam exposure apparatus at a predetermined angle (beam deflection angle) at a predetermined distance in a region other than the main pattern forming portion region of the resist film, and at the same time, the driving stage is operated. A step of drawing by moving, and a step of scanning the main pattern in a region where a main pattern is to be formed of the resist film by a predetermined distance (beam deflection angle) with an electron beam, and simultaneously moving the drive stage. A drawing step, and scanning the electron beam for a predetermined distance (beam deflection angle) with another auxiliary pattern paired with the auxiliary pattern in a region other than the main pattern formation planned region of the resist film, By moving the drive stage, it is drawn so as to overlap the auxiliary pattern. And a step of detecting a positional relationship between the pair of auxiliary patterns.

Such a conventional method of inspecting a resist pattern is to measure the positional relationship between a pair of auxiliary patterns formed before and after the formation of the main pattern, that is, the positional deviation, that is, to estimate the formation accuracy of the main pattern by analogy. is there.

However, in the above-described detection of the positional relationship between the pair of auxiliary patterns in the conventional resist pattern forming method, since the information for measuring and estimating the formation accuracy of the main pattern is only the positional stability during writing, the electron beam Cannot be evaluated with higher accuracy.

(Problems to be Solved by the Invention) It is an object of the present invention to accurately evaluate the accuracy of a main pattern by detecting the scan width of an electron beam before and after the main pattern is formed, as well as the positional stability during writing. To provide a method of inspecting a resist pattern on a substrate by an electron beam exposure apparatus capable of performing the above.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a raster scan type electron beam exposure apparatus having a stage movable in the X and Y directions. In the method of forming a pattern on a film and inspecting, while moving the stage in one direction, an electron beam is applied to a resist film region on the substrate other than a main pattern formation scheduled portion with respect to a direction perpendicular to the stage moving direction. A first drawing operation of scanning a predetermined distance at a predetermined angle with an electron beam to draw in a direction perpendicular to the stage moving direction, moving the stage in the opposite direction, and moving the electron beam in a direction perpendicular to the stage moving direction. Is scanned at a fixed angle at a predetermined angle to the stage, A second drawing operation for drawing in a right angle direction, and the stage is moved in one direction in the same manner as the first drawing operation, and at least a third drawing operation for scanning the electron beam is performed. The first sub-pattern of the first sub-pattern, which is drawn adjacent to each other in the drawing operation and drawn in pairs in the same drawing operation and over the two adjacent drawing operations, forming two pairs of rectangular pattern elements having a predetermined positional relationship with each other Forming step, while moving the stage in one direction and the opposite direction, scanning the electron beam at a predetermined angle with respect to the direction perpendicular to the stage movement direction on the resist film area on the substrate in the main pattern formation scheduled portion. Forming a main pattern for writing an electron beam in a direction perpendicular to the stage moving direction; And moving the electron beam to a resist film area on the substrate other than the main pattern formation area and adjacent to the first sub-pattern formation area. A first drawing operation in which scanning is performed at a certain distance with an angle and drawing is performed in a direction perpendicular to the moving direction of the stage by the electron beam, and the stage is moved in the opposite direction, and the electron beam is moved in a direction perpendicular to the stage moving direction. Scan a certain distance at a predetermined angle,
A second drawing operation of drawing in a direction perpendicular to the moving direction of the stage by an electron beam, and further moving the stage in one direction in the same manner as the first drawing operation, and moving the electron beam in a direction perpendicular to the stage moving direction. By performing at least a third drawing operation for scanning a predetermined distance at a predetermined angle with respect to each of the linear pattern elements drawn adjacent to each other in each of the drawing operations and the linear pattern elements drawn in the first drawing operation. Are drawn adjacent to a linear pattern element drawn by a drawing operation in a final step of the first sub-pattern forming step, and two pairs of rectangular pattern elements having a predetermined positional relationship with each other in design are the same. Forming a second sub-pattern to be drawn within the drawing operation and over two adjacent drawing operations, respectively. First and second in the process of forming
Observing the connecting portions of the linear pattern elements adjacent to each other drawn by the drawing operation and the connecting portions of the linear pattern elements adjacent to each other drawn by the second and third drawing operations. Ridge lines on the same side of two pairs of rectangular pattern elements drawn in the same drawing operation and two adjacent drawing operations in the forming process of the first sub-pattern and having a predetermined positional relationship with each other in design. Measuring the distance between them to detect the state of the scan width of the electron beam, and when the first sub-pattern is normally drawn, the first and second drawing in the step of forming the second sub-pattern A connecting portion of linear pattern elements adjacent to each other drawn by the operation, and a linear pattern adjacent to each other drawn by the second and third drawing operations The connection accuracy is detected by observing the connection part of the turn element, and when the first sub-pattern is drawn normally, the connection is drawn by the drawing operation in the final step in the step of forming the first sub-pattern. Detecting a step at a connecting portion between the linear pattern element and the linear pattern element drawn by the first drawing operation in the step of forming the second sub-pattern, and the first sub-pattern is drawn normally Ridge lines on the same side of two pairs of rectangular pattern elements having a predetermined positional relationship with each other in the same drawing operation and two adjacent drawing operations in the forming process of the second sub-pattern. Technical measures are taken to measure the distance between them to detect the state of the scan width of the electron beam.

(Operation) According to the present invention, not only the positional stability during writing but also the scan width of the electron beam can be detected before and after the main pattern is formed. In addition, it is possible to observe connection portions of adjacent linear pattern elements drawn by the first and second drawing operations and the second and third drawing operations in the forming process of the first sub-pattern, respectively. By observing the connecting portions of linear pattern elements adjacent to each other drawn by the first and second drawing operations and the second and third drawing operations in the sub-pattern forming step, and detecting the connection accuracy, Pass / fail of the main pattern can be determined. Therefore, the formation state of the main pattern can be evaluated with high accuracy.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to FIG. 1 and FIG.

Pattern formation in this embodiment is performed by a raster scan type electron beam exposure apparatus (not shown) having a stage (not shown) movable in the XY direction. In the electron beam exposure apparatus, scanning of the electron beam is controlled by a deflection system. The deflection system includes a pair of X-direction deflection electrodes (parallel plate electrodes) and a pair of Y-direction deflection electrodes (parallel plate electrodes), and a voltage is applied to each pair of electrodes.

First, the glass substrate 1 covered with a resist film (not shown) is fixed on a stage (not shown). Subsequently, the stage is moved in _one direction (S1 direction), and a voltage is applied to the X-direction deflection electrode and the Y-direction deflection electrode of the electron beam exposure apparatus to move the electron beam from the left side to the right side in FIG. A direction (X) perpendicular to the stage movement direction (Y direction)
A first drawing operation is performed in which scanning is performed at a predetermined distance (predetermined deflection angle) with respect to the direction of the stage and at a right angle to the moving direction of the stage by the electron beam. Thus, the linear pattern element 2 ₁ with a constant width as shown in FIG. 2 on the resist film of the substrate first region other than the main pattern forming scheduled portion (W), 2 ₂ is drawn.

Furthermore, with moving the stage in the opposite direction (S ₂ direction), the electron of the electron beam from the left in the next step by scanning a certain distance at a predetermined angle with respect to the stage moving direction perpendicular to the direction to the right A second drawing operation is performed in which the beam is drawn in a direction perpendicular to the moving direction of the stage. Thereby, the linear pattern element
2 _3, 2 ₄ is drawn, the Cactus mark 3 then consists of a rectangular pattern element 3 ₁ to 3 ₅ are drawn.

Next, the stage is moved in _one direction (S1 direction), and the electron beam is scanned from left to right in the next step in the same manner as in the first drawing operation to perform a third drawing operation, whereby a rectangular pattern is formed. containing 3 _6, 3 ₇ is drawn, then a linear pattern element 2 _5, 2 ₆ is drawn in.

Incidentally, the second drawing two rectangular patterns containing 3 ₁ depicted in operation, 3 ₂ and the second, the third rendering depicted in operation two rectangular patterns containing 3 _3, 3 _6, respectively design They have a predetermined positional relationship with each other.

By performing such first to third drawing operations,
Linear pattern element 2 ₁ to 2 ₆ in the resist film region on the substrate 1 other than the main pattern forming scheduled portion to be described later, the first sub-pattern 4a formed of rectangular patterns containing 3 ₁ to 3 ₇ is formed.

Next, while moving the stage, a voltage is applied to the X-direction deflecting electrode and the Y-direction deflecting electrode of the electron beam exposure apparatus so that the electron beam moves from left to right by a predetermined angle in a direction perpendicular to the stage moving direction. The main pattern 5 is formed by scanning the electron beam on the resist film of the glass substrate 1 in a direction perpendicular to the direction of movement of the stage by scanning at a certain distance with an angle. Thereafter, a second sub-pattern 4b is formed on the resist film region of the substrate 1 adjacent to the first sub-pattern 4a .

That is, the stage is moved in _one direction (S1 direction), and a voltage is applied to the X-direction deflection electrode and the Y-direction deflection electrode of the electron beam exposure apparatus to move the electron beam from left to right in the stage movement direction. By performing a first drawing operation of scanning a predetermined distance at a predetermined angle with respect to the right angle direction and writing with the electron beam in a direction perpendicular to the moving direction of the stage, the first sub pattern 4a is adjacent to the first sub pattern 4a . the rectangular pattern containing 3 _{8-3 11} as shown in FIG. 2 is drawn on the resist film of the substrate first region, then a linear pattern containing 2 _7, 2 ₈ is drawn in.

Furthermore, with moving the stage in the opposite direction (S ₂ direction), the electron of the electron beam from the left in the next step by scanning a certain distance at a predetermined angle with respect to the stage moving direction perpendicular to the direction to the right Second drawing by a beam in a direction perpendicular to the direction of movement of the stage
By performing the drawing operation, the linear pattern elements 2 ₉ , 2 ₁₀
There is drawn, Cactus mark 3 consisting of a rectangular pattern element 3 _{12-3 16} 'is drawn subsequently.

Next, the stage is moved in _one direction (S1 direction), and a third drawing operation for scanning the electron beam from the left to the right in the next step in the same manner as the first drawing operation is performed. Elements 2 ₁₁ and 2 ₁₂ are drawn.

Incidentally, the second sub-pattern 4b first drawing operation and drawn respectively third rendering operation in the step of forming the first sub-pattern 4a 2 two rectangular patterns containing 3 in the formation process of _9, 3 _7, the 1, the two rectangular pattern elements 3 ₁₂ , 3 ₁₃ drawn over the second drawing operation, and the second
Two rectangular drawn with the drawing operation pattern element 3 _10, 3 _14,
Each has a predetermined positional relationship with each other in design.

As described above, the first sub-pattern 4a formed prior to the formation of the main pattern 5 detects (1) the accuracy of connection between adjacent pattern elements and (2) the state of the scan width of the electron beam. Can be.

(1) In the first sub-pattern 4a, the pattern-containing 2 ₂ drawn by the first drawing operation and the second drawing operation, 2 ₃ of the connecting portion X ₁
In this state, it is possible to detect the connection accuracy when the movement of the stage is changed from one direction to the opposite direction.

Similarly, detecting the connection accuracy when changing the movement of the stage from the opposite direction from the second drawing operation and the third drawing operation pattern containing 2 ₄ painted, 2 ₅ state of the joint portion Y ₁ of the one-way Can be.

Further, the connection accuracy of observation, the first linear pattern element 2 ₂ drawn by the second drawing operation, 2 ₃ of connection accuracy in the determination, that the forward connection accuracy, the second,
The third rendering operation in a linear pattern containing 2 ₄ painted, 2 ₅ connection accuracy of, i.e. by observing both the backward connection accuracy, the determination of connection accuracy can be more reliably grasped.

(2) second drawing two rectangular patterns containing 3 ₁ operating in a mutually design painted with a predetermined positional relationship, 3 ₂ of the same side, for example, the distance a ₁ of the left ridge, second, third rectangular pattern element 3 ₃ having a design together predetermined positional relationship depicted in drawing operation, 3 the same side of the _6, for example, by measuring the right edges of the distance b _1, respectively, detect the state of the scan width of the electron beam can do.

Therefore, the state of the scan width of the electron beam before the formation of the main pattern 5 can be detected from the information of the first sub-pattern 4a described above. In addition, the quality of the main pattern can be inferred from the accuracy of the connecting portion of the linear pattern elements adjacent to each other.

In the first sub-pattern 4a, a beam shape from the rectangular pattern element 3 _1, 3 ₃ of the corner portion c ₁ and the rectangular pattern element 3 _2, 3 ₃ of the connection status corners d ₁ constituting the cactus mark 3 You can check.

Next, when the first sub-pattern 4a is normally drawn, the first
Second sub-pattern 4b formed adjacent to sub-pattern 4a
Thus, it is possible to detect (1) the connection accuracy of adjacent pattern elements, (2) the positional stability during writing, and (3) the state of the scan width of the electron beam after the main pattern 5 is formed.

(1) connecting portions of the first in the second sub-pattern 4b, the pattern element 2 ₈ drawn in the first drawing operation and the second drawing operation, 2 ₉
X ₂ in the state, when changed to the opposite direction to movement of the stage from one direction from the state of the joint portion Y ₂ of the second drawing operation, and the third writing pattern element 2 ₁₀ drawn in operation, 2 _11, and from the opposite direction It is possible to detect the connection accuracy when changing in one direction.

(2) Third drawing operations in drawn linear patterns containing 2 ₅ a connecting portion E ₃ of the linear pattern containing 2 ₇ drawn in the first drawing operation of the second sub-pattern 4b states of the first sub-pattern 4a , And thereby the position stability during writing can be detected.

(3) first, and the distance a ₂ between the right side edges of the second drawing operation of two with astride design together predetermined positional relationship depicted in the rectangular pattern element 3 _12, 3 _13, second draw by measuring the distance b ₂ between the two rectangular patterns element 3 _10, 3 ₁₄ left ridge with design mutually predetermined positional relationship drawn in the operation, to detect the state of the scan width of the electron beam Can be.

Therefore, the positional stability in the electron beam exposure device after the formation during and formation of the main pattern 5 from the information of the second sub-pattern 4b described above in the case where the first sub-pattern 4a is drawn successfully, and the electron beam Scan width state can be detected. In addition, the quality of the main pattern can be determined based on the accuracy of the joint between the linear pattern elements adjacent to each other.

Incidentally, to measure the distance e ₃ of the rectangular pattern element 3 ₉ drawn in the first drawing operation of the third rendering operation in a rectangular pattern element 3 ₇ depicting the second sub-pattern 4b of the first sub-pattern 4a, the position during the formation of the main pattern as described in (2) of the second sub-pattern 4b described above from the relationship between the distance e ₃ and the distance a ₁ described in (2) of the first sub-pattern 4a (or b ₁₎ Stability can be supplementarily evaluated.

Further, rectangular pattern element 3 ₁₂ that constitutes the cactus mark 3 'of the second sub-patterns 4b, 3 ₁₄ corners c ₂ and the rectangular pattern element 3 of _13, 3 ₁₄ main pattern formation after the connection state corner d ₂ of Beam shape can be confirmed.

Thus, the first sub-pattern 4a is drawn before the formation of the main pattern, and the state of the optical system of the exposure apparatus can be evaluated based on this. Therefore, the main pattern 5 is formed after the optical system has been corrected. Further, by drawing the second sub-pattern 4b adjacent to the first sub-pattern 4a after the formation of the main pattern, the second sub-pattern 4b itself and the first and second sub-patterns 4a , 4b are drawn.
By comparison, the state during the drawing of the main pattern can be estimated by analogy. As a result, the accuracy evaluation of the main pattern 5 can be checked.

In the above embodiment, a glass substrate is used as the substrate. However, the present invention is not limited to this, and another substrate such as a semiconductor wafer may be used.

(Effects of the Invention) As described above in detail, according to the method for inspecting a resist pattern on a substrate by the electron beam exposure apparatus according to the present invention, not only the positional stability during writing but also the scan width of the electron beam and the like can be controlled by the main pattern. Can be detected before and after the formation of the main pattern, so that the formation state of the main pattern can be evaluated with higher accuracy, and as a result, a remarkable effect that can be effectively used in the manufacture of a semiconductor device or a photomask in which a fine pattern is indispensable is produced. Things.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a pattern formed on a glass substrate by the method of the present invention, and FIG. 2 is an enlarged explanatory view of a sub-pattern of FIG. 1 ... glass substrate, 2 ₁ to 2 ₁₂ ... linear pattern element, 3 ₁ to 3 ₁₆ ...
Rectangular pattern elements, 4a : first sub-pattern, 4b : second sub-pattern, 5: main pattern.

Claims (1)

(57) [Claims] 1. A method for forming a pattern on a resist film on a substrate mounted on a stage by a raster scan type electron beam exposure apparatus having a stage movable in an XY direction and inspecting the resist film. While moving in one direction, the electron beam scans the resist film area on the substrate other than the part where the main pattern is to be formed at a predetermined angle with respect to the direction perpendicular to the stage movement direction and moves the stage by the electron beam. A first drawing operation for drawing in a direction perpendicular to the direction, moving the stage in a reverse direction, and scanning the electron beam at a predetermined angle with respect to a direction perpendicular to the stage moving direction for a predetermined distance. A second drawing operation for drawing in a direction perpendicular to the stage movement direction, and the first drawing The stage is moved in one direction in the same manner as the work, and at least a third drawing operation for scanning the electron beam is performed so that the linear pattern elements are drawn adjacent to each other in each drawing operation, and a predetermined number A first sub-pattern forming step of drawing two pairs of rectangular pattern elements having a positional relationship within the same drawing operation and over two adjacent drawing operations, and moving the stage in one direction and in the opposite direction While scanning, the electron beam is scanned at a predetermined angle with respect to the direction perpendicular to the stage movement direction on the resist film region on the substrate in the portion where the main pattern is to be formed, and the electron beam is drawn in the direction perpendicular to the stage movement direction. Forming a main pattern; moving the stage in one direction; An electron beam is scanned at a predetermined angle with respect to a resist film region on the substrate other than the formation region and adjacent to the first sub-pattern formation region at a predetermined angle with respect to a direction perpendicular to the stage moving direction, and the stage is moved by the electron beam. 1st drawing in the direction perpendicular to the moving direction of
Drawing operation, while moving the stage in the opposite direction,
A second drawing operation of scanning the electron beam at a predetermined angle with respect to a direction perpendicular to the stage moving direction at a predetermined distance, and drawing the electron beam in a direction perpendicular to the moving direction of the stage by the electron beam; Similarly, the linear pattern element is moved by moving the stage in one direction and performing at least a third drawing operation of scanning the electron beam at a predetermined distance at a predetermined angle with respect to a direction perpendicular to the stage moving direction. In each drawing operation, drawing is performed adjacent to each other, and the linear pattern element drawn in the first drawing operation is made adjacent to the linear pattern element drawn in the drawing operation in the final step of the first sub-pattern forming step. Two pairs of rectangular pattern elements which are drawn in a drawing and have a predetermined positional relationship with each other in the same drawing operation and adjacent to each other. Forming a second sub-pattern to be drawn over two drawing operations, respectively, wherein adjacent linear patterns respectively drawn by the first and second drawing operations in the first sub-pattern forming step The connection accuracy of the first sub-pattern forming step is detected by observing the connection portions of the element and the connection portions of the linear pattern elements adjacent to each other drawn by the second and third drawing operations. The distance between the ridges on the same side of two pairs of rectangular pattern elements having a predetermined positional relationship with each other in design in the drawing operation and the two adjacent drawing operations is measured to determine the scan width of the electron beam. Detecting a state, and in a case where the first sub-pattern is normally drawn, the first and second sub-pattern forming steps are performed.
Observe the connected portions of linear pattern elements adjacent to each other drawn in the second drawing operation, and the connected portions of linear pattern elements adjacent to each other drawn in the second and third drawing operations, respectively. When the connection accuracy is detected, and when the first sub-pattern is normally drawn, the linear pattern element drawn by the drawing operation in the final step of the first sub-pattern forming step and the second sub-pattern Detecting a step at a connecting portion with a linear pattern element drawn by the first drawing operation in the forming step of the first sub-pattern, and when the first sub-pattern is normally drawn, Two pairs of rectangular patterns having a predetermined positional relationship with each other in design in the same drawing operation and two adjacent drawing operations in the formation process Inspection of the resist pattern to the substrate by electron beam exposure apparatus for detecting the state of the scan width of the electron beam by measuring respective distances between ridges of the same side, it is characterized by the.