JP3370317B2 - Drawing method of pattern plate having alignment pattern and pattern plate drawn by the method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a pattern plate having an alignment pattern (mark) for alignment, and more particularly to a reticle mask and a shadow for projecting a pattern onto a wafer or a master mask substrate. The present invention relates to a method of drawing a large-sized pattern plate used for a mask or the like and a pattern plate drawn by the method.

[0002]

2. Description of the Related Art In recent years, ICs and LSIs have become more highly integrated, and 4 Mbit DRAMs have already entered the mass production stage and are shifting to 16 Mbits and 64 Mbits. Along with this, the dimensions of the circuit elements on the wafer are required to be further miniaturized, and miniaturization is also required for the pattern formation by the lithographic technique for producing the circuit elements on the wafer. .

There are usually the following three methods for forming a pattern on a wafer. The first method is a method using an EB (electron beam) apparatus or an FIB (focused ion beam) apparatus, in which the electron beam or ion beam is controlled to directly form a pattern on the wafer. In this case, since the drawing position is controlled according to the pattern on the wafer, the patterning accuracy depends only on the position detection ability and the drawing position control ability. And there are still some problems in the position detection ability and the position control ability. This method
Since the pattern is created one by one, it takes a lot of time for drawing, so it is not suitable for mass production. The second method is
It is a method of transferring this to a wafer substrate using a mask that has a pattern of the same size as the pattern of each chip formed on the wafer called a mask pattern, and it is mass-produced because it is a batch exposure. But 1:
Since the first transfer is performed, the alignment accuracy with the pattern on the wafer is synergistic with the pattern alignment accuracy. Then, the influence of the distortion of the master mask directly affects the accuracy. The third method is a method in which a mask having a pattern 5 times to 10 times larger than the pattern of a wafer or a master mask called a reticle mask is used, and this is subjected to reduction projection exposure onto a wafer substrate. This method is excellent in accuracy because it reduces the alignment (overlap) accuracy error between the pattern on the wafer and the pattern of the reticle mask due to the reduced projection, and because it is batch exposure, it is productive. Is said to be advantageous over the EB and FIB methods.

However, as described above, due to the demand for higher integration of IC and LSI elements, further miniaturization of the pattern on the wafer has come to be required.
Further accuracy is required for the overlay accuracy (positional accuracy) of the pattern on the wafer and the created pattern.

Under these circumstances, even in the reduction projection exposure method which is the third pattern forming method which is advantageous in terms of the overlay accuracy with the pattern on the wafer, the overlay accuracy at the current level (0.04 to 0.02 μm) is obtained. ) Better accuracy is required. In the case of a DRAM, the overlay accuracy at the 16 Mbit level is required to be 0.02 to 0.01 μm or less. With this method, 1
Usually, 10 or more reticle masks are required to create one LSI, and the overlay accuracy between the patterns reduced and projected by each reticle mask is 0.0.
It is required to be 2 to 0.01 μm or less.

Further, in the field of color televisions and displays, the size has been increasing more and more in recent years, and the shadow masks and liquid crystal panels used for them have also been required to be large. Pattern masks for shadow masks and liquid crystal panels are required to be smaller and finer (finer), and when an optical exposure machine is used, a desired pattern can be obtained by combining the patterns corresponding to the apertures. The number of aperture exposures increases, and along with that, the total exposure time increases, which may extend to day and night. Furthermore, when an electron beam exposure apparatus is used, a raster machine that draws a pattern by combining raster scanning and blanking takes an enormous amount of time because of area dependence, and a vector that vector scans a shaped beam is used. Even when a machine is used, since the scanning is performed corresponding to the aperture as in the case of the light exposure machine, the time for the exposure drawing becomes long.

[0007]

By the way, when a reticle pattern is drawn by using an electron beam exposure apparatus, a raster machine is usually used. However, the drawing method is performed with a mask substrate fixed on a stage. Under the position control system using a laser interferometer, etc., the substrate is irradiated and exposed with an electron beam while the stage is moved, and a predetermined pattern is exposed and drawn. Is controlled to be turned on and off in a predetermined address unit and is irradiated. However, with the miniaturization of patterns,
In order to manufacture a fine pattern with high accuracy, it is necessary to reduce the address size, which is a unit of drawing, and the drawing time increases accordingly.

Further, the vector type electron beam exposure apparatus is a drawing method in which a predetermined aperture image is irradiated and a pattern is produced by combining these, but in order to produce a fine pattern with high accuracy, the diameter of the aperture is used. Must be small, and as the size of the device becomes finer, the drawing time increases dramatically.

As described above, when the drawing time becomes longer with the miniaturization of the pattern, the temperature fluctuation of the substrate to be drawn often occurs even in an apparatus that is precisely managed and controlled, such as an electron beam exposure apparatus. There is a problem that the drawing accuracy is lowered due to electrical fluctuations, mechanical fluctuations, fluctuations in the position control system, and the like. In particular, in the case of a pattern plate having an alignment pattern such as a reticle mask, the position of the main pattern is controlled by the alignment pattern on the premise of an accurate positional relationship between the alignment pattern and the main pattern (device pattern). Therefore, it is necessary that the positional relationship between the alignment pattern and the main pattern is accurately drawn, but this positional relationship is also affected by the above items (1) to (3). Similarly, in the case of a shadow mask and a pattern plate for a liquid crystal panel, the above-mentioned effects (1) to (3) are also affected.

In most cases, the above-mentioned fluctuations (1) to (1) are caused in one direction only, and is due to the difference between the temperature of the substrate itself and the ambient temperature of the stage used, and is electrically dependent. Is caused by a cassette or the like for fixing the substrate to be exposed, and the cassette is gradually displaced during the X, Y movement of the stage. It is considered that is due to atmospheric pressure and temperature fluctuations of the environment of the interferometer. In general, most of and are affected by the drawing size of the substrate and are almost proportional to the size of this pattern, and most of are
Although it is said that it is affected by the drawing time, in any case, there is a positional deviation (error) that is proportional to the drawing size and occurs according to the pattern size, and a positional deviation that occurs proportionally to the drawing time. Be divided. In particular, the deviation due to is a problem, and when the deviation is large, the relative position between the alignment pattern and the main pattern becomes defective. It should be noted that the positional deviation that occurs depending on the pattern size is relatively small.

The present invention has been made in view of such circumstances, and an object thereof is to provide a drawing method capable of accurately drawing the positional relationship between an alignment pattern and a main pattern in a pattern plate having an alignment pattern. That is.

[0012]

A method of drawing a pattern plate having an alignment pattern of the present invention which achieves the above-mentioned object is a method of forming a pattern plate having a main pattern such as a reticle pattern and a shadow mask pattern and an alignment pattern for alignment. In the drawing method, at least draw the alignment pattern before drawing this pattern, and
This method is characterized in that after the main pattern is drawn, the alignment patterns are overlapped and drawn again to correct the relative positional deviation between the alignment pattern and the main pattern, which fluctuates during the main pattern drawing.

In this case, the alignment pattern drawn before the main pattern drawing and the alignment pattern drawn after the main pattern drawing can be shifted by a predetermined distance, and the alignment pattern of the same shape can be drawn during the main pattern drawing. It is also possible to draw by overlapping.

Further, the drawing can be performed by either an electron beam exposure apparatus or an optical exposure apparatus. The pattern plate to be drawn is a reticle pattern master plate, a shadow mask pattern master plate, or the like.

The present invention includes a pattern plate having an alignment pattern drawn by the above drawing method.

[0016]

According to the present invention, at least the alignment pattern is drawn before the main pattern is drawn, and after the main pattern is drawn, the alignment pattern is created by overlapping and drawing the alignment patterns of the same shape again. In comparison with the case where the alignment pattern is created by drawing once before or after the main pattern is drawn, the relative positional deviation between the alignment pattern and the main pattern, which varies depending on the time of the drawing system during the main pattern drawing, is almost It is possible to perform complete correction, and reduce the decrease in drawing position accuracy that varies depending on the size of the pattern.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A description will be given below, with reference to the drawings, of an example in which the drawing method of a pattern plate having an alignment pattern of the present invention is applied to a reticle mask.

As shown in the plan view of FIG. 1, a main pattern B forming a device pattern and alignment patterns A1, A2, A3 passing through the center of the main pattern B in the X direction and the center of the Y direction are arranged around the main pattern B. When manufacturing a pattern plate, a position control system such as a laser interferometer and an X, Y stage drive system are used, and exposure drawing is performed by an electron beam exposure apparatus or an optical exposure apparatus in the following order by an electron beam drawing apparatus or the like. To do. That is, firstly, the alignment pattern A1,
Draw A2 and A3, then draw this pattern B,
Subsequently, the alignment patterns A1, A2,
A3 is drawn on top of the first drawing.

In this way, the alignment patterns A1,
By exposing and drawing A2 and A3 before and after the main pattern B is drawn, the alignment patterns A1, A2, and A are drawn.
The accuracy of the positional relationship between 3 and the main pattern B is improved. In particular, the relative positional deviation between the alignment pattern and the main pattern, which is caused by the above-mentioned fluctuations during the main pattern writing, is almost completely corrected, and the decrease in the drawing position accuracy caused by the above is reduced.

The principle of correcting the relative positional deviation between the alignment pattern and the main pattern by exposing and drawing the alignment patterns A1, A2 and A3 before and after the main pattern B is drawn as described above will be described below. 2, with reference to FIG. Here, for the sake of simplicity, the positional deviation only in the X direction will be described.
The same applies to the Y direction.

As shown in FIG. 2, the design dimension of the main pattern B is L and the actual drawing dimension is L + s. If this deviation s is the sum of the deviation σ that is substantially proportional to the pattern size and the deviation Σ that is substantially proportional to the drawing time, the alignment pattern A1 ′ drawn at the first time and the center of the main pattern B drawn next are The positional deviation Δ1 of Δ1≈ (L + s) / 2−L / 2 = s / 2 = (σ + Σ) /
It becomes 2.

By the way, as shown in FIG. 3, when the line width in one drawing of the alignment pattern is W1, the line 1 drawn in the first time and the line 2 drawn in the second time are drawn.
The difference between and is σ / 2 + Σ. Therefore, the line width W of the entire alignment pattern drawn at the first and second times is W1 + σ / 2 + Σ. Therefore,
The positional deviation Δ2 between the center of the line 1 drawn for the first time and the line center of the entire alignment pattern A1 is Δ2≈ (W1 + σ / 2 + Σ) / 2−W1 / 2 = σ / 4 +
It becomes Σ / 2.

As described above, the center of the alignment pattern A1 and the main pattern B created by drawing twice
The positional deviation Δ from the center is Δ≈Δ1-Δ2 = (σ + Σ) / 2- (σ / 4 + Σ / 2)
= Σ / 4 That is, comparing the method according to the present invention with the conventional method in which the alignment pattern is not overlaid and drawn only once before or after the main pattern B, in the case of the present invention,
The center of the alignment pattern A1 is only deviated from the center of the main pattern B by Δ≈σ / 4, and the positional deviation Σ depending on the drawing time does not intervene, whereas in the conventional case, Δ1≈ (σ + Σ). A shift of / 2, a shift proportional to the pattern size is almost twice as large as that of the present invention, and a position shift depending on the writing time is equivalent to half of the whole writing time. That is, according to the present invention, the relative positional deviation Σ / 2 between the alignment pattern and the main pattern, which is caused by the fluctuation during writing of the main pattern, is almost completely corrected, and the positional accuracy of the drawing is decreased σ / 2. Is reduced to almost half.

The first drawing position and the second drawing position of the alignment pattern are set in advance as shown in FIG.
Even if the design is shifted by a certain distance M and drawn,
In exactly the same manner, the relative positional deviation Σ / 2 between the alignment pattern and the main pattern, which is caused by the variation during writing of the main pattern, is almost completely corrected, and the decrease in the drawing position accuracy σ / 2 caused by the It can be reduced to half.

As described above, the pattern plane drawing method of the present invention uses the intermediate position of the alignment pattern, which is created by overlapping and drawing the main pattern before and after the drawing, as the center position of the alignment pattern, and the drawing deviation amount of the main pattern. The deviation amount of the alignment pattern is adjusted in accordance with the above, and the deviation from the design value of the positional relationship with the center of the main pattern is corrected. The alignment mark drawing method of the present invention is
As is clear from the principle, this pattern is particularly suitable for a reticle mask for a highly integrated semiconductor device, a pattern for a large-scale, high-density shadow mask, and the like, which has a large size, a complicated pattern, and requires drawing time.

By the way, in the rare cases where the changing directions of 1 to 3 are not constant directions, the exposure drawing of the alignment pattern is not limited to before and after the main pattern, and may be inserted several times during the drawing of the main pattern. You can deal with it to some extent.

The above is the method of correcting the alignment pattern by overlapping and drawing the alignment pattern before and after the main pattern is drawn according to the drawing deviation amount of the main pattern. The main pattern B and the alignment patterns A1 and A as shown in FIG.
2 and A3 are drawn, and after that, the actual positional deviation between the main pattern B and the alignment patterns A1, A2, and A3 is measured without touching the main pattern B having the deviation in drawing, and the alignment patterns A1, A2, and A3 are measured. Can be corrected to correct the deviation from the design value of the positional relationship with the center of the main pattern.

This example will be described in detail below.
FIG. 5 shows the actual pattern B and the alignment patterns A1, A2, A3 after actual drawing and development. Further, in FIG. 5, the coordinates where this pattern is to be positioned are indicated by a chain line with reference to the alignment patterns A1, A2 and A3. The order of drawing is that the alignment pattern A after the main pattern B is drawn.
1, A2, A3 may be drawn or vice versa,
In addition, drawing may be performed in other order and is not particularly limited. After drawing and developing, the actual positional deviation of the main pattern B in the X direction is measured by a coordinate position measuring device or the like. As shown in the figure, for example, ΔW ₁ is above the reference position on the upper side and ΔW is above the reference position on the lower side. _If it is displaced by ₂ , the alignment pattern A1 in the X direction is relatively displaced from the actual main pattern B by (ΔW ₁ + ΔW ₂ ) / 2 = ΔW. Therefore, it is necessary to move the alignment pattern A1 upward by ΔW.

As described above, in order to move the alignment pattern A1 in the predetermined direction, the portion orthogonal to the moving direction of the alignment pattern A1 is thickened to the moving side by twice the moving amount Δw, or conversely, the moving side. On the opposite side of
It is sufficient to make it twice as thin as w. That is, in the case of thickening, as shown in FIG. 6A, the + X side of the alignment pattern A1 is expanded by adding 2ΔW.
By doing so, the center of the alignment pattern A1 moves by ΔW from the position before the correction to the + X side, and the purpose can be achieved. Also, in the case of thinning, FIG.
As shown in (b), -X of the alignment pattern A1
Narrow the side by 2ΔW. By doing this, the center of the alignment pattern A1 is still + X from the position before correction.
It will move ΔW to the side.

The alignment patterns A2 and A3 are similarly corrected.

Further, the alignment patterns A1, A
When the main pattern B is rotated with respect to 2, A3 or has an angular deviation, the positions of the other alignment patterns A3 or A2, A1 are set in the same manner as described above with reference to the alignment pattern A2 or A3. To move. This will be briefly described with reference to FIG. 7. For example, when the main pattern B has a clockwise angular deviation as shown with reference to the pattern A2, the upper pattern A3 is relative to the main pattern B. Since it is shifted to the left side, the amount of the shift is measured, and the alignment pattern A3 is moved to the right side corresponding distance by the method shown in FIG. Along with this, the X-axis slightly rotates in the direction connecting the alignment pattern A2 and the newly set alignment pattern A3.
The alignment pattern A1 serving as the position reference in the X direction is also moved upward by a distance determined by this rotation angle. Since an actual reticle mask is a composite of parallel displacement and rotational displacement, the alignment pattern accuracy can be improved by combining the above-described position displacement and angle displacement correction methods.

In the above method, a part of the light-shielding film of the alignment pattern once formed may be shaved (see FIG. 6).
(B)), to add a part of it (Fig. 6 (a)),
Various methods are used. For example, a light shielding film may be partially added to the pattern portion as shown in FIG. 6A by using a focused ion beam pattern white defect repairing device and a laser pattern white defect repairing device which are conventionally used. Part of the pattern portion may be deleted as shown in FIG. 6B by using a focused ion beam pattern black defect repair device and a laser pattern black defect repair device. Further, using a spot exposure device, a direct drawing device, etc., a resist is partially made into a plate, and a pattern material is vapor-deposited on an additional portion through the formed opening, or conversely etched to form a pattern. You may make it remove a part. Other,
Various film forming methods and film peeling methods can be used.

In the above, when the distortion of the main pattern B is small, the deviation ΔW ₁ or ΔW ₂ on either side may be used as the relative position deviation ΔW.

In this way, the actual pattern B and the alignment patterns A1, A2, A3 are drawn, and the actual pattern B and the alignment patterns A1, A2, A3 are not touched and the actual pattern B and the alignment patterns A1, A2, A3 are not touched. By measuring the positional deviation and correcting the alignment patterns A1, A2, A3 to correct the deviation from the design value of the positional relationship with the center of the main pattern, the main pattern drawing similar to the method of FIG. It is possible to almost completely correct the relative positional deviation between the alignment pattern and the main pattern. Furthermore, this correction method is also an advantageous method in that it enables a reticle mask or the like that has been conventionally unusable due to poor positional accuracy of the alignment pattern.

In the above description of FIGS. 1 to 7, the reticle mask for semiconductor exposure having the alignment pattern on the periphery has been described. However, the drawing method and the correction method of the present invention use the alignment for alignment. It can also be applied to drawing a shadow mask pattern plate having a pattern, an electrode pattern plate for a liquid crystal panel, and the like.

[0036]

As described above, according to the method of drawing a pattern plate having an alignment pattern of the present invention and the pattern plate drawn by the method, at least the alignment pattern is drawn before the main pattern is drawn, and Since the alignment pattern is created by drawing the alignment patterns of the same shape again after the main pattern is drawn, compared with the conventional case where the alignment pattern is created by drawing once before or after the main pattern is drawn, The relative positional deviation between the alignment pattern and the main pattern, which fluctuates depending on the drawing system time during the main pattern drawing, is almost completely corrected, and the decrease in the drawing position accuracy, which fluctuates depending on the pattern size, is reduced. can do.

Therefore, (1) it is possible to manufacture the alignment pattern and the main pattern with high positional accuracy, and it is possible to cope with miniaturization of a reticle or the like. (2) It is possible to provide a drawing method that manages the positional accuracy of the alignment pattern and the main pattern, which can cope with changes in the temperature of the substrate, electric changes, mechanical changes, changes in the position control system, and the like during drawing. (3) Even for a large-sized pattern such as a shadow mask original plate, a drawing method can be provided in which the drawing time and the positional accuracy between the alignment pattern and the main pattern due to the size are managed.

[Brief description of drawings]

FIG. 1 is a plan view for explaining the order of drawing a reticle mask according to an embodiment of the present invention.

FIG. 2 is an overall plan view of a reticle mask for explaining the principle of correcting the relative position deviation between the alignment pattern and the main pattern of the present invention.

FIG. 3 is a view similar to FIG. 2 showing an alignment pattern portion.

FIG. 4 is a view similar to FIG. 2 showing an alignment pattern portion of another example.

FIG. 5 is a plan view showing a positional relationship between a main pattern which is actually drawn and developed and an alignment pattern.

FIG. 6 is a plan view of an alignment pattern portion for explaining a method of moving an alignment pattern.

FIG. 7 is a plan view for explaining a correction method when the main pattern is misaligned with respect to the alignment pattern.

[Explanation of symbols]

A1, A2, A3 ... Alignment pattern B ... Book pattern A1 '... Alignment pattern drawn the first time 1 ... Line of the alignment pattern drawn the first time 2 ... Line of the alignment pattern drawn the second time

─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-63-288018 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03F 1/08 H01J 9/14 H01L 21 / 027

Claims (8)

(57) [Claims] 1. A method of drawing a pattern plate having a main pattern such as a reticle pattern and a shadow mask pattern and an alignment pattern for alignment, wherein at least the alignment pattern is drawn before the main pattern is drawn and after the main pattern is drawn. , This pattern is being drawn by drawing the alignment pattern again.
Between the alignment pattern that fluctuates over time and this pattern
A drawing method of a pattern plate having an alignment pattern, which is characterized by correcting a positional deviation . 2. A pattern plate having an alignment pattern according to claim 1, wherein an alignment pattern drawn before the main pattern is drawn and an alignment pattern drawn after the main pattern are drawn by a predetermined distance from each other. Method. 3. The method of drawing a pattern plate having an alignment pattern according to claim 1, wherein alignment patterns of the same shape are drawn in an overlapping manner during the drawing of this pattern. 4. The method of drawing a pattern plate having an alignment pattern according to claim 1, wherein the drawing is performed by an electron beam exposure apparatus. 5. The method for drawing a pattern plate having an alignment pattern according to claim 1, wherein the patterning is carried out by an optical exposure device. 6. The pattern plate to be drawn is a reticle pattern original plate, according to any one of claims 1 to 5.
A method of drawing a pattern plate having the alignment pattern according to the item. 7. The method of drawing a pattern plate having an alignment pattern according to claim 1, wherein the pattern plate to be drawn is a shadow mask pattern original plate. 8. A pattern plate having an alignment pattern drawn by the drawing method according to claim 1. Description: