JPH06302492A - Exposure condition inspection pattern, exposure original plate and exposure method using them - Google Patents

Abstract

PURPOSE:To provide an exposure condition inspecting pattern, which quantitatively controls and stably keeps the accuracy of a product pattern to be transferred to the material to be exposed, an exposure original plate and exposure method which uses the pattern and the plate. CONSTITUTION:An exposure condition testing pattern 10 is composed of a light shielding pattern 11, which is formed by arranging the summits 11c and 11d of the corners of a pair of triangle patterns 11a and 11b formed of chromium light shielding film at a prescribed interval A, and a translucent pattern 12, which is formed by taking out the triangle patterns 12a and 12b from the chromium light shielding film so as to be translucent and by arranging the summits 12c and 12d to face at a prescribed interval B. The A+B, which is the sum of the measured values of the intervals A and B, reflects defocus quantity not depending on the exposure quantity, and since the difference B-A does not depend on the defocus quantity but reflects exposure quantity, the causes of the exposure condition fluctuation are discriminated and quantitative inspection is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure inspection pattern, an exposure original plate, and an exposure technique using them, and more particularly to a technique effective when applied to a photolithography process using an exposure original plate such as a photomask or reticle. is there.

[0002]

2. Description of the Related Art Conventionally, in a photolithography process in which a circuit pattern is transferred and formed on a semiconductor wafer or the like by using an exposure master plate such as a photomask or a reticle, how to form a resist layer having a thickness of about 1 μm on the wafer, The problem is whether to faithfully transfer and form the pattern on the photomask or reticle.

In particular, in a projection type exposure apparatus (hereinafter referred to as a stepper) which has become mainstream in recent years, the degree of integration of circuit patterns to be exposed on a wafer is increased, and accordingly, the line width of the pattern to be transferred is also increased. It is in the submicron range. The formation of such a minute pattern is a value close to the limit even in the stepper, and it is necessary to set both the exposure amount and the focus position with high accuracy.

However, for example, the exposure dose varies depending on the reflectance of the base of the wafer and the coating thickness of the resist,
The focus position also gradually changes according to the atmospheric pressure and the amount of light transmitted through the lens. As described above, both the exposure amount and the focus position require delicate control in the wafer process and are variable factors. If either of the two conditions of the exposure amount and the focus position deviates from the set value, there arises a problem that a desired pattern transferred onto the resist cannot be obtained accurately.

Therefore, conventionally, a special test reticle having a resolution chart is mounted on a stepper, and the test pattern is subjected to trial baking under various exposure conditions for the resist on the wafer, so that the resist pattern after development is formed. Optimal values of exposure amount and focus position are obtained by visual observation. Using the exposure amount and focus position thus obtained, the same pattern was repeatedly exposed thereafter.

However, as described above, as a result of the resolution line width becoming a value close to the limit, the test pattern is exposed, and after visual observation, a time elapses until the product wafer is exposed again. In some cases, the exposure conditions may change, and it has been desired to form the exposure condition confirmation pattern on the product wafer.

One of them is, for example, Japanese Patent Laid-Open No. 2-46.
A wedge-shaped pattern disclosed in Japanese Patent Publication No. 462 (hereinafter, referred to as a first conventional technique) is known. In the first conventional technique, a wedge-shaped pattern is provided on a reticle as shown in FIG. 11A, and a resist pattern on a wafer generated by exposure (in FIG. 11A, a hatched portion represents a resist). (Shown) is irradiated with a sheet-shaped laser beam,
The diffracted light generated at the pitch of the wedge pattern is detected. The wedge tip of this wedge pattern is
When the exposure amount increases or when the focus position is different from the optimum position, the resolution disappears and disappears. Therefore, FIG.
As shown in (b), when the diffracted light intensity obtained by irradiating the position of the wedge-shaped pattern with the sheet-shaped beam is measured, the diffracted light intensity equal to or higher than a predetermined threshold is obtained because the wedge-shaped pattern is formed. It is limited to the area where That is, when the width of the diffracted light intensity above the threshold is wide, it indicates that the exposure conditions are correct, and when the width is narrow, it indicates that the exposure conditions are not set correctly and the resist pattern is short. become.

Similarly, in the technique disclosed in Japanese Patent Laid-Open No. 61-61417 (hereinafter referred to as the second conventional technique), it is easy to visually determine the exposure condition as shown in FIG. A pattern has been proposed. That is, FIG.
The rectangular pattern shown in Figure 4 is provided on the reticle so that it can be understood that the pattern was formed under the correct exposure conditions if the minimum size of the pattern exposed and developed on the wafer matches the resolution limit of the projection optical system. Is.

Further, in the technique disclosed in Japanese Patent Laid-Open No. 60-140346 (hereinafter referred to as the third conventional technique), a square pattern having a diagonal as a reference line as shown in FIG. 13 has a uniform pitch. Arrange them to change in the difference sequence,
The aim is to be able to visually measure the change in the size of the resist pattern due to the increase or decrease in the exposure amount by contact or non-contact of the adjacent portion of the pattern formed on the wafer.

[0010]

In any of the above-mentioned first to third prior arts, in any case, a resist pattern obtained under correct exposure conditions is used as a reference, and a resist formed for the reference pattern is used. The aim is to quantitatively calculate how much the pattern dimensions are changing. However, in the first to third prior arts, when the exposure conditions were incorrect, it was not possible to clearly distinguish whether the cause was the exposure amount or the focus position shift (defocus). Further, in the first to third conventional techniques, the evaluation pattern has a large area, and it is difficult to easily provide it on a part of the product pattern, and the measurement SEM (Sc
It was difficult to observe with a high magnification (narrow field of view) using an anning Electron Microscope (scanning electron microscope).

On the other hand, in the second prior art, although the cause of the exposure failure can be specified and the area occupied by the pattern can be reduced, the isolated dot pattern may peel off during the process to become a foreign substance. Further, if the number of patterns is small, the resolution of the obtained information is low, and conversely, if the resolution is high, the number of patterns is increased and the occupied area is increased.

That is, in the above-mentioned first to third conventional techniques, the pattern occupying area is generally large, and it is formed on a part of the test reticle as an exposure condition evaluation pattern and is used for daily maintenance of the apparatus. However, it is very difficult to provide it on a product reticle, transfer it to a part of an actual product wafer, and use it for evaluation of exposure conditions in an actual process.

The object of the present invention is small enough to coexist with a product pattern, and can be stably transferred to an object to be exposed, and a precise measurement at a high magnification by a length-measuring SEM or the like makes it easy to quantify a factor of variation in exposure conditions. It is to provide an exposure condition test pattern that can be tested.

Another object of the present invention is to provide an exposure master plate capable of quantitatively managing the accuracy of a product pattern transferred to an object to be exposed and stably maintaining it.

Still another object of the present invention is to provide an exposure method capable of preventing the occurrence of defects in the exposure process by quantitatively testing the exposure conditions.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0017]

Among the inventions disclosed in the present application, a brief description will be given to the outline of typical ones.
It is as follows.

That is, the exposure condition test pattern of the present invention is formed in the exposure area on the exposure original plate, and has a first pattern in which light-shielding first corner portions having a desired apex angle are opposed to each other. And a second pattern in which light-transmissive second corner portions having a desired apex angle are opposed to each other.

According to the present invention, in the exposure condition test pattern according to claim 1, the interval A between the apexes of the first corners of the first pattern transferred from the exposure original plate to the object to be exposed and the second pattern. The sum of the space B between the vertices of the second corner of the pattern (A
+ B) and the difference (BA), it is discriminated whether the change of the exposure condition is caused by the change of the exposure amount or the change of the focus position.

The exposure condition test pattern of the present invention is
A pair of third corner portions, which are formed in the exposure area on the exposure original plate, have translucency and light-shielding properties opposite to each other and are convex in the same direction, are formed on the same axis.

The exposure condition test pattern of the present invention is
A pair of fourth corner portions, which are formed in the exposure area on the exposure original plate and have opposite translucency and light-shielding properties and are convex in opposite directions, are formed on the same axis.

Further, the exposure original plate of the present invention is provided with the exposure condition inspection pattern according to claim 1, 2, 3 or 4 in a part of the exposure area.

In the exposure master of the present invention, a quality control area composed of a plurality of sections arranged in a grid pattern is provided in the exposure area, and each of the sections is a product pattern formed in the exposure area. The exposure condition test pattern according to claim 1, 2, 3 or 4 is formed by properly using each type or each transition of the exposure process.

According to the present invention, in the exposure master according to claim 5 or 6, an address pattern indicating the positions of a plurality of sections is formed on the outer peripheral portion of the quality control area, and the address pattern is observed when the exposure condition verification pattern is observed. By referring to the pattern, it is possible to identify which product pattern or exposure process the exposure condition test pattern formed in each section corresponds to.

Further, the exposure method of the present invention is characterized in that
Using the exposure condition test pattern described in 2, 3, or 4,
The resolution condition of a product pattern consisting of at least one of the focus position and exposure amount of the exposure optical system is tested.

The present invention also provides the exposure method according to claim 8, wherein the value of the sum (A + B) in the exposure condition test pattern according to claim 1 or 2, or the fourth value in the exposure condition test pattern according to claim 4. The distance C between the vertices of the corners is controlled so as to be equal to or less than a predetermined standard value.

In the exposure method according to the present invention, the difference (BA) value in the exposure condition test pattern according to claim 1 or 2 or the exposure condition test pattern according to claim 3 is used. The distance D between the vertices of the third corner is managed so as to fall within a predetermined maximum and minimum standard value.

[0028]

According to the above-described exposure condition test pattern of the present invention, for example, when a positive type resist is formed on an object to be exposed and exposed, the second transparent corner portion of the second pattern is exposed. In the transfer pattern of No. 2, the transfer pattern expands as the exposure amount increases, and as a result, the interval B between the apexes of the opposing second corner decreases, and the defocus amount increases and the interval B between the apexes increases.

On the other hand, the distance A between the vertices of the first light-shielding corners of the first pattern increases as the exposure amount and defocus amount increase. That is, as the defocus amount increases, the distance B between the vertices of the light-transmitting second corners of the second pattern and the distance A between the vertices of the second light-shielding corners of the first pattern are both To increase.

From this fact, conversely, it is understood that the exposure conditions are changed due to defocus when the distances A and B between the vertices of the transfer patterns of both the first and second patterns are increasing. . When the interval B between the vertices of the translucent second corner transfer pattern increases and the interval A between the vertices of the light-shielding first corner transfer pattern decreases,
The exposure amount is insufficient, and conversely, the distance B between the vertices of the translucent second corner transfer pattern decreases and the distance A between the vertices of the light-shielding first corner transfer pattern increases. Indicates that the exposure amount is excessive.

That is, the increasing / decreasing tendency of the distance A between the vertices of the transfer pattern at the first corner and the distance B between the vertices of the transfer pattern at the second corner due to the exposure amount is completely opposite, and defocusing occurs. Since the increasing and decreasing trends of A and B are the same, the value of the sum (A + B) does not depend on the exposure amount because the increase and decrease of A and B resulting from the exposure amount are offset, and the increase and decrease due to the defocus amount. Will be added and emphasized to represent the defocus amount.

On the contrary, the value of the difference (B−A) is canceled by the variation of the defocus amount because both A and B have the same increasing tendency, and does not depend on the defocus amount, but on the exposure amount. The increase / decrease in A and B caused by the stress is emphasized, and the increase / decrease in the exposure amount is reflected.

As described above, by measuring the dimension of the distance A between the vertices of the first corner and the distance B between the vertices of the second corner, the cause of the change in the exposure condition is the excessive exposure amount. Is it due to lack or due to defocus,
Can be easily revealed. At this time, the exposure amount and the focus position are changed in advance, the values of A and B at that time are measured for the transfer pattern transferred to the exposed object, and the result is created as a calibration curve or a calibration table. In this case, the change in the exposure condition generated on the object to be exposed can be immediately and quantitatively obtained from the measurement results of A and B.

Further, as in the exposure condition test pattern according to the third aspect, a pair of third projections formed in the exposure area on the exposure original plate, the translucency and the light blocking property being opposite to each other and convex in the same direction. When the corner portions are formed on the same axis, the distance D between the vertices of the third corner portion indicates the value of the difference (BC) in the exposure condition test pattern according to claim 1. Excess or deficiency of the exposure amount can be verified by one measurement operation.

Further, as in the exposure condition test pattern according to the fourth aspect, a pair of fourth portions which are formed in the exposure area on the exposure original plate and have the translucency and the light shielding property which are opposite to each other and which are convex in the opposite directions to each other. When the corners of are formed on the same axis, the value of the interval C between the vertices of the fourth corner indicates the value of the sum (A + B) in the exposure condition test pattern according to claim 1.
The defocus amount can be verified with a single measurement operation.

Further, according to the above-mentioned exposure original plate of the present invention, since the exposure condition inspection pattern according to claim 1, 2, 3 or 4 is provided in a part of the exposure area, Therefore, the exposure condition verification pattern is transferred together with the transfer of the actual product pattern, and it is possible to accurately manage the exposure conditions of the actual product pattern by measuring the exposure condition verification pattern on the exposed object. Therefore, the accuracy of the product pattern transferred to the object to be exposed can be stably maintained. For example, in the light area,
By providing a quality control area consisting of a plurality of sections arranged in a grid pattern, and using each section separately for each type of product pattern formed in the exposure area or each transition of the exposure process, It is also possible to easily manage the history of exposure conditions. Further, by forming an address pattern in the peripheral portion so that a plurality of sections arranged in a grid pattern can be identified, when observing the exposure condition verification pattern, the position of the exposure condition verification pattern is located at which address pattern position. Depending on the presence of the compound, it is possible to rapidly test the exposure condition in a specific exposure process.

Further, according to the exposure method of the present invention, by using the exposure condition inspection pattern according to claim 1, 2, 3 or 4, a product pattern including at least one of the focus position and the exposure amount of the exposure optical system can be obtained. Since the resolution condition is verified, the actual exposure work and the exposure condition verification work can be simultaneously performed in parallel, and the occurrence of defects in the exposure process can be prevented.

In practice, for example, the above sum (A + B)
By controlling the value of C or the value of C so as to be equal to or less than a predetermined standard value, it becomes possible to accurately and quantitatively control the variation of the exposure condition due to defocus within a target range. Similarly, for example, the value of the above-mentioned difference (BA),
Alternatively, it is possible to quantitatively control the exposure amount to a target value by controlling the value of D so as to fall within a predetermined maximum and minimum standard value.

[0039]

EXAMPLES Examples of the present invention will be described in detail below.

(Embodiment 1) FIGS. 1, 2, 3 and 4
FIG. 5 is a plan view showing an example of an exposure condition inspection pattern which is an embodiment of the present invention, and FIGS. 5 and 6 are diagrams for explaining an example of its action.

FIG. 7 and FIG. 8 are schematic plan views showing an example of the exposure original plate of this embodiment, and FIG. 10 is a schematic perspective view showing an example of an exposure apparatus for performing an exposure operation using the same. Is.

First, a stepper as an example of the exposure apparatus of this embodiment will be briefly described with reference to FIG.

In FIG. 10, monochromatic light (g line: 436 nm, or i line: 3) from a light source such as a mercury lamp not shown.
The reticle 1, which is an example of the exposure original plate, is illuminated with (65 nm) as illumination light. At the center of the reticle 1, the wafer 4
IC, L to be transferred to the resist formed on top
The product pattern 2 such as SI is formed by, for example, etching a light-shielding film made of chromium formed on a glass substrate into a desired pattern to open a light-transmitting portion.

The transmitted light of the reticle 1 forms an image on the wafer 4 via the reduction lens 3. On the surface of the wafer 4, a resist sensitive to the transmitted light is deposited and formed, for example, with a thickness of 1 μm, and the product pattern 2 of the reticle 1 is transferred. Wafer 4 moves horizontally in a two-dimensional plane X
The Y stage 5 and the Z stage 6 that moves vertically in the optical axis direction of the reduction lens 3 are mounted on a precision movement table. The stepper is a device for repeatedly stacking product patterns 2 such as circuit patterns on the reticle 1 on the wafer 4,
Although not specifically shown, a reticle alignment optical system for correctly aligning the reticle 1 with the apparatus, a reticle moving table, a rotary stage for matching the rotational positions of the wafer 4 and the reticle 1 around the optical axis, and the wafer 4 A wafer pattern (positioning pattern) detection optical system for detecting the pattern formed in the previous step and overprinting a new product pattern 2 and moving the wafer 4 in the optical axis direction to the focus position of the reduction lens 3. A height detector or the like for detecting the height of the surface of the wafer 4 when the wafers 4 are matched with each other is mounted.

Next, an example of the exposure condition inspection pattern 10 in this embodiment will be described with reference to FIG. The exposure condition verification pattern 10 of the present embodiment is arranged at four corners in the periphery of the exposure area on the reticle 1, as illustrated in FIG.

In FIG. 1, the shaded region shows the chrome remaining portion (light-shielding portion) of the chrome pattern formed on the glass substrate in the reticle 1. That is, the exposure condition test pattern 10 of this embodiment has a pair of triangular patterns 11a formed of a chrome light-shielding film.
And the apex 11 of each corner of the triangular pattern 11b
c and the apex 11d are arranged so as to face each other with a predetermined space A, and, for example, the triangular pattern 12a and the triangular pattern 12b are removed from a substantially rectangular chrome light-shielding film to make it transparent. , And the apex 12c and the apex 12d of both corners are arranged to face each other at a predetermined interval B.

The apex 11c of the corner of the light-shielding pattern 11,
11d, and the apex 12 of the corner of the translucent pattern 12
The angles θ of c and 12d become more sensitive to changes in exposure conditions as the angle becomes sharper, but ultimately it is important to determine according to the limit resolution of the stepper used. In the case of this embodiment, as an example, θ is set to 44 °.

Further, the distance A and the distance B between the vertices of the light-shielding pattern 11 and the light-transmitting pattern 12 respectively.
For example, assuming that measurement is performed at a high magnification using a length-measuring SEM, 1 μm or less when transferred onto the wafer 4 is considered to be effective from the relationship with the observation visual field of the length-measuring SEM.

The exposure condition test pattern 1 shown in FIG.
When 0 is transferred onto the wafer 4 to form a resist pattern, the triangular pattern 1 of the light-shielding pattern 11 is formed.
If 1a and 11b are too fine, they may be peeled off from the wafer 4 to cause foreign matter. Therefore, it is considered desirable that the length dimension of the triangular patterns 11a and 11b in the facing direction is, for example, 5 μm or more in the state of being transferred onto the wafer 4. On the other hand, in order to form the exposure condition inspection pattern 10 shown in FIG. 1 on the reticle 1, it is necessary to form it on the peripheral portion of the product reticle 1 at each exposure step with severe resolution. For example, the scribe area 2a (wafer It is desirable that the external dimensions be such that a large number can be formed within a plurality of rectangular chip formation regions arranged in a grid on the upper surface of the four.

Although the actual dimensions are not shown in FIG.
In view of the above-mentioned circumstances, for example, in order to transfer and form the entire exposure condition inspection pattern 10 on the resist on the wafer 4 at a square of 20 μm, the triangular patterns 11a and 11 are formed.
This can be achieved by setting the bases of b, 12a and 12b to about 8 μm and the distances A and B between the vertices to 0.5 μm.

Next, the operation of the exposure condition test pattern 10 illustrated in FIG. 1 will be described with reference to FIGS. 5 and 6.

The distance A + B between the vertices 11c and 11d of the light-shielding pattern 11 and the distance B between the vertices 12c and 12d of the light-transmitting pattern 12 shown in FIG. FIG. 5 shows a result calculated by a simple optical simulation corresponding to. In this simulation, an i-line NA0.5 reduction lens is used in the projection optical system, and its coherency δ is set to 0.5.
5, the distance between the vertices A and B is close to the limit resolution 0.4.
μm. As a result, as shown in FIG. 5A, the sum A + B of the distances A and B between the vertices of the light-shielding pattern 11 and the light-transmitting pattern 12 formed on the resist on the wafer 4 is the optimum exposure value. Even under the condition, it is about 2.5 μm, but the defocus is the depth of focus (D = λ / 2NA ² = 0.7).
3 μm), the value of the sum A + B rapidly increases and becomes 3 μm.
It can be seen that the value exceeds m.

On the other hand, at that time, as shown in FIG.
There is little change in the value of the sum A + B with respect to the change in the exposure amount. That is, if the exposure amount is substantially appropriate (for example, within ± 20%), for example, the defocus amount can be immediately calculated from the value of the sum A + B from the relationship shown in FIG.

FIG. 5 shows the simulation result.
Practically, it is desirable to obtain the relationship illustrated in FIG. 5A in advance by a preliminary experiment using the wafer 4 that is used in the exposure process of the corresponding product.

On the other hand, the difference between the distance A between the vertices on the light-shielding pattern 11 side and the distance B between the vertices on the light-transmitting pattern 12 side,
For example, FIG. 6 shows the result of calculating B-A by simulation with respect to the change of the exposure condition. The value of the difference B−A is insensitive to defocus as shown in FIG. 6A (can be ignored if defocus is within ± 1 μm), but as shown in FIG. Be sensitive to fluctuations in quantity. This difference B-A is also the sum A + B of FIG.
Similar to the case, it is necessary to acquire and organize the actual applicable product process in advance. The data in FIG. 5 and FIG. 6 are different from each other only in the way of arrangement using the same experimental result, and the work does not require much labor. That is,
Exposure is performed on the corresponding product wafer by changing the exposure amount and the focus position using the corresponding reticle, and the distances A and B between the apexes of the resist pattern on the wafer after development may be measured using the length measuring SEM. . At this time, the vertices 11c and 11d and the vertices 12c and 12 of the light-shielding pattern 11 and the light-transmitting pattern 12 constituting the exposure condition inspection pattern 10 are formed.
If d is arranged close to each other, the intervals A and B can be simultaneously measured at one place under one exposure condition. That is, the exposure condition verification pattern 10 at one location within the exposure range
If you measure, the target calibration table can be easily obtained.
And the calibration curve illustrated in FIG. 6 can be obtained.

FIG. 7 shows an example in which the exposure condition inspection pattern 10 of this embodiment is arranged on the reticle 1 used in the actual exposure process.

By arranging the scribe areas 2a on the left and right surrounding the formation area of the product pattern 2 at four positions, that is, the upper and lower sides, the image plane of the reduction lens 3 and its inclination, and the image plane and the wafer due to other causes. It is possible to prevent defective resolution due to the inclination of the surface of No. 4.

In recent years, due to the increase in resolution required by the miniaturization of product patterns, the defocus amount is
It is necessary to manage not for the entire wafer 4 but for each shot (each transfer area of each product pattern 2) individually.

For this reason, the occupied area is small, and it can be easily incorporated in a part of the actual product pattern 2. Moreover, it can be easily and clearly determined whether the exposure amount is excessive or deficient or the defocus amount influences the exposure condition. The exposure condition test pattern 10 of the present embodiment that can be discriminated is effective by quantitatively and finely managing the exposure condition in shot units.

Further, as described above, since the exposure condition test pattern 10 of this embodiment can be formed in a square of about 20 μm, when the scribe area 2a is 120 μm, as shown in FIG. If the columns and the longitudinal direction have the same size, the quality control regions 20 composed of a total of 36 exposure condition inspection patterns 6 in 6 rows can be arranged at the four peripheral positions illustrated in FIG. 7. And the required number of steps,
According to the width of the scribe area 2a, the required number of exposure condition inspection patterns 10 in the quality control area 20 and the arrangement shape (the number of rows and the number of columns) can be determined.

By arranging the quality control area 20 in this manner, the exposure condition inspection pattern 10 showing the resolution for each process can be listed, so that, for example, whether or not the defective product causes defective resolution. Or, in case of poor resolution,
It is possible to easily specify which process.

Further, as illustrated in FIG. 9, of the 6 rows × 6 columns section of the quality control area 21, one row and one column at the outermost periphery are used as the exposure condition test pattern in the quality control area 21. By assigning to the formation of the address pattern 22 composed of numbers or alphabetic characters indicating the positions of 10 and referring to the address pattern 22 when measuring the exposure condition verification pattern 10, the individual exposure condition verification pattern 1
It is possible to accurately identify and record 0, and it is possible to more accurately perform the analysis work of the cause of the product defect.

(Embodiment 2) FIG. 2 is a schematic plan view showing an example of the configuration of an exposure condition inspection pattern which is another embodiment of the present invention.

Exposure condition verification pattern 30 of the second embodiment
Includes a corner portion 31 and a corner portion 32, which have opposite translucency and light shielding properties, in a part of the contour.
Is convex in the same direction (to the left in FIG. 2) and is on the same axis, and each vertex 31a and vertex 32a has a predetermined interval.

As a result, the measured value of the distance C between the vertices 31a and 32a of each of the corners 31 and 32 is shown in FIG. 1 because the light-shielding property and the light-transmitting property of the corners 31 and 32 are opposite to each other. The difference B-A in the illustrated exposure condition test pattern 10 will be represented.

That is, by measuring the interval C of the exposure condition test pattern 30 of this embodiment, it is possible to directly quantitatively test the excess or deficiency of the exposure amount with one measurement operation. As a result, it is possible to obtain an advantage that the verification operation of the exposure condition becomes simpler and the required space can be reduced.

As shown in FIG. 3, the exposure condition test pattern 40 shown in FIG. 2 in which the entire light-transmitting property and light-shielding property are reversed is used. The same effect as the pattern 30 is obtained.

That is, on the contour of the inner peripheral portion of the exposure condition test pattern 40, the corner portions 41 and 42 having opposite translucency and light shielding properties are formed coaxially in a convex manner in the same direction. The measured value of the distance C between the apex 41a and the apex 42a is also the exposure condition test pattern 1 illustrated in FIG.
The value reflects the difference B-A at 0.

(Third Embodiment) FIG. 4 is a schematic plan view showing an example of the structure of an exposure condition inspection pattern which is still another embodiment of the present invention.

The exposure condition test pattern 50 in the third embodiment is such that corner portions 51 and corner portions 52 having opposite translucency and light shielding property and convex in opposite directions are formed on the same axis. The distance between the vertices 51a and 52a is set to a predetermined value.

In the case of this exposure condition test pattern 50, since the corners 51 and 52 having opposite translucency and light blocking properties are arranged so as to oppose each other in the opposite directions, the apex 51a and the apex 52a are opposite. The measured value of the interval D is a value that reflects the sum A + B in the exposure condition verification pattern 10 illustrated in FIG.

That is, by measuring the interval D of the exposure condition verification pattern 50 of this embodiment, the defocus amount can be directly and quantitatively verified.

As a result, the operation of verifying the exposure conditions becomes simpler and the required space can be reduced.
The advantage is obtained.

If the exposure condition inspection pattern 50 of this embodiment illustrated in FIG. 4 and the exposure condition inspection pattern 30 illustrated in FIG. 2 or the exposure condition inspection pattern 40 illustrated in FIG. Both exposure and defocus can be tested simultaneously.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.

In the above description, the case where the invention made by the present inventor is mainly applied to the exposure process of the semiconductor wafer which is the field of application which is the background of the invention has been described.
The present invention is not limited to this, and can be widely applied to a technique in which it is required to precisely transfer the pattern of the exposure original plate to the object to be exposed through light.

[0077]

The effects obtained by the representative one of the inventions disclosed in the present application will be briefly described as follows.

That is, according to the exposure condition test pattern of the present invention, it is small enough to coexist with the product pattern and can be stably transferred onto the object to be exposed, so that it can be easily incorporated into a part of the exposure process of the actual product. Accurate measurement at high magnification (narrow field of view) using measuring SEM etc. is easy, and it is easy to quantitatively test the factors that change the exposure conditions such as exposure amount and defocus in the actual exposure process. The effect is obtained.

Further, according to the exposure master plate of the present invention, the accuracy of the product pattern transferred to the object to be exposed can be quantitatively controlled and stably maintained in the actual exposure process. It is possible to obtain the effect that the yield can be improved.

Further, according to the exposure method of the present invention, by quantitatively verifying the exposure conditions, it is possible to prevent the occurrence of defects in the exposure process and improve the product yield in the exposure process. The effect is obtained.

[Brief description of drawings]

FIG. 1 is a plan view showing an example of an exposure condition inspection pattern which is an embodiment of the present invention.

FIG. 2 is a plan view showing an example of an exposure condition inspection pattern which is another embodiment of the present invention.

FIG. 3 is a plan view showing an example of an exposure condition inspection pattern which is a modified example thereof.

FIG. 4 is a plan view showing an example of an exposure condition inspection pattern which is still another embodiment of the present invention.

5 (a) and 5 (b) are diagrams for explaining an example of the action of the exposure condition test pattern according to the embodiment of the present invention.

6 (a) and 6 (b) are diagrams for explaining an example of the action of the exposure condition test pattern according to the embodiment of the present invention.

FIG. 7 is a schematic plan view showing an example of an exposure original plate which is an embodiment of the present invention.

FIG. 8 is a plan view showing an example of the configuration of a quality control area.

FIG. 9 is a plan view showing a modification thereof.

FIG. 10 is a schematic perspective view showing an example of an exposure apparatus that performs an exposure operation using an exposure condition verification pattern that is an embodiment of the present invention.

11A and 11B are conceptual diagrams showing an example of a conventional technique.

FIG. 12 is a conceptual diagram showing an example of a conventional technique.

FIG. 13 is a conceptual diagram showing an example of a conventional technique.

[Explanation of symbols]

 1 reticle (exposure master) 2 product pattern (exposure area) 2a scribe area 3 reduction lens 4 wafer (object to be exposed) 5 XY stage 6 Z stage 10 exposure condition verification pattern 11 light-shielding pattern (first pattern) 11a triangular shape Pattern 11b Triangular pattern 11c Vertex (first corner) 11d Vertex (first corner) 12 Translucent pattern (second pattern) 12a Triangular pattern 12b Triangular pattern 12c Vertex (second corner) ) 12d Vertex (second corner) 20 Quality control area 21 Quality control area 22 Address pattern 30 Exposure condition verification pattern 31 Corner (third corner) 31a Vertex 32 Corner 32a Vertex (third corner) 40 exposure condition verification pattern 41 corner (third corner) 41a vertex 42 corner (third corner) 4 a vertex 50 exposure condition test pattern 51 corner (fourth corner) 51a apex 52 corner (fourth corner) 52a vertices

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takahiro Machida 5-20-1, Josuihonmachi, Kodaira-shi, Tokyo Inside the Semiconductor Division, Hitachi, Ltd. (72) Inventor Akira Maejima 5 Minamimizumoto-cho, Kodaira-shi, Tokyo Hitachi Co., Ltd., Semiconductor Company, Ltd., Semiconductor Company, Ltd. (72) Masamichi Kobayashi, 5-20-01, Mizusuihonmachi, Kodaira-shi, Tokyo, Ltd., Semiconductor Company, Ltd., Hitachi, Ltd. (72) Inventor, Takeshi Kato, Tokyo 5-20-1 Kamimizuhonmachi, Kodaira-shi Incorporated company Hitachi Ltd. Semiconductor Division

Claims (10)

[Claims] 1. A first pattern, which is formed in an exposure region on an exposure master and has light-shielding first corner portions having a desired apex angle facing each other, and translucency having a desired apex angle. And a second pattern in which the second corners of are opposed to each other. 2. A distance A between the vertices of the first corner of the first pattern transferred from the exposure master to an object to be exposed.
Based on the sum (A + B) and the difference (BA) of the space B between the vertices of the second corner of the second pattern,
The exposure condition test pattern according to claim 1, wherein it is discriminated whether the change of the exposure condition is caused by the change of the exposure amount or the change of the focus position. 3. A pair of third corner portions, which are formed in an exposure area on an exposure master and have opposite translucency and light-shielding properties and are convex in the same direction, are formed on the same axis. The characteristic exposure condition test pattern. 4. A pair of fourth corner portions, which are formed in an exposure area on an exposure master and have opposite translucency and light-shielding properties and convex in opposite directions, are formed on the same axis. Exposure condition test pattern. 5. The method according to claim 1, 2, 3 in a part of the exposure area.
Alternatively, an exposure original plate having the exposure condition inspection pattern described in 4. 6. A quality control area comprising a plurality of sections arranged in a grid pattern is provided in the exposure area, and each of the sections is exposed for each type of product pattern formed in the exposure area or for exposure. The exposure original plate according to claim 5, wherein the exposure condition inspection pattern according to claim 1, 2, 3 or 4 is formed by selectively using it for each transition of the process. 7. An address pattern indicating a position of each of the plurality of sections is formed on an outer peripheral portion of the quality control area, and the address pattern is referred to when observing the exposure condition verification pattern, whereby each section The exposure original plate according to claim 5 or 6, wherein it is possible to identify which of the product patterns or the exposure process the exposure condition test pattern formed on corresponds to. 8. The resolution condition of a product pattern comprising at least one of a focus position and an exposure amount of an exposure optical system is tested by using the exposure condition verification pattern according to claim 1, 2, 3 or 4. Exposure method. 9. The value of the sum (A + B) in the exposure condition verification pattern according to claim 1 or 2, or 4.
9. The exposure method according to claim 8, wherein the distance C between the vertices of the fourth corner in the exposure condition test pattern is controlled so as to be equal to or less than a predetermined standard value. 10. The value of the difference (BA) in the exposure condition test pattern according to claim 1 or 2, or the distance D between the vertices of the third corners in the exposure condition test pattern according to claim 3. 9. The exposure method according to claim 8, wherein the exposure is controlled so as to fall within a predetermined maximum and minimum standard value.