JP3283085B2 - Laser beam control 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 laser beam control method for controlling focusing of a laser beam.

2. Description of the Related Art A laser drawing apparatus for drawing a fine pattern such as an optical integrated circuit pattern and a hologram is required to automatically focus a beam diameter.

[0003]

2. Description of the Related Art Conventionally, in an autofocus of a laser beam drawing apparatus, a laser interferometer using a near-infrared semiconductor laser is disposed above a drawing objective lens, and a distance between the laser and the substrate is set to a predetermined distance. Was adjusted as follows.

In addition, in order to draw a waveguide pattern having a desired line width on a photoresist using a laser beam drawing apparatus, for example, it is necessary to adjust a laser beam to a size as large as the line width. Conventionally, this adjustment has been performed by irradiating a photosensitive laser beam onto the photoresist.

[0005]

Therefore, the above-mentioned autofocus system using the laser interferometer has the feature that the measurement resolution is very high, but the optical system becomes complicated and information is fed back. However, the weight load of the Z stage to be moved increases, and the price becomes expensive. In addition, there is a problem that continuing irradiation with a beam having a very high energy density adversely affects the photoresist.

In the latter method of performing the focusing by irradiating the photoresist with the laser beam, the focusing is performed by applying the He-Cd laser to the photoresist at the position where the patterning is started. There has been a problem that the photosensitivity of the photoresist is increased and becomes larger than a desired line width, and in particular, it becomes impossible to perform patterning such that the lines come close to each other.

[0007] The present invention solves these problems,
Automatic focusing is performed based on the area when the object is irradiated with the laser beam, enabling automatic focusing with a very simple and lightweight optical system, and using a non-photosensitive laser beam. It is intended to make it possible to draw a pattern with a uniform line width by eliminating an undesired pattern width increase due to exposure at the time of auto focus after performing auto-focusing with a photosensitive laser beam. .

[0008]

Means for solving the problem will be described with reference to FIGS. 1, 2, 5 and 10.

Referring to FIGS. 1, 2, 5 and 10,
The detector 14 irradiates the object 8 with a laser beam through the objective lens 12 and detects the reflected laser.

The area measuring unit 21 determines the beam spot areas S 1, S 1 on the object 8 based on a signal from the detector 14.
1 ′ is measured. The Z adjustment processing unit 24 compares the measured beam spot area S1 with the designated area S0, and calculates a movement amount ΔZ in the Z direction corresponding to the error.

The Z-adjustment processing section 27 compares the non-photosensitive measured beam spot area S1 'with the designated area S0' and calculates the Z-direction movement amount ΔZ for the error. is there.

The height table 29 is for setting a movement amount ΔZ calculated by the Z adjustment processing section 27 for a predetermined position of the whole drawing object 8. The position detecting section 31 detects a branch point of the pattern and stores the position (X, Y, Z).

The redrawing processing section 32 performs redrawing from the branch point of the pattern.

[0014]

According to the present invention, as shown in FIG. 1, FIG. 2 and FIG. 5, a laser beam is applied to the object to be drawn 8 by an objective lens 12, a reflected laser is detected by a detector 14, and an area measuring unit is provided. Numeral 21 measures the beam spot area S1 on the object 8 based on the signal from the detector 14, compares the beam spot area S1 measured by the Z adjustment processing unit 24 with the designated area S0, and calculates the error. The movement amount ΔZ in the Z direction corresponding to the minute is calculated, and the distance between the objective lens 12 and the object 8 is moved by the calculated movement amount ΔZ.

At this time, every time the irradiation position of the laser beam is moved by a predetermined distance, the movement amount ΔZ is calculated to move the distance between the objective lens 12 and the object 8 to be drawn.
The object to be drawn 8 is irradiated with a non-photosensitive laser beam through the objective lens 12, and the reflected laser is detected by the detector 14, and the area measuring unit 21 detects the reflected laser based on the signal from the detector 14. The non-photosensitive beam spot area S1 'on the object 8 is measured, and the beam spot area S1' measured by the Z adjustment processing unit 27 is compared with the designated area S0 '. The movement amount ΔZ in the direction is calculated, and the objective lens 12 and the object to be drawn 8 are moved by the calculated movement amount ΔZ.
And try to move the distance.

Further, a height table 29 is provided, and a movement amount ΔZ is calculated and set for each predetermined position of the whole drawing object 8 by the Z adjustment processing section 27, and a photosensitive laser beam is irradiated. When a pattern is drawn on the object 8 by drawing, ΔZ corresponding to the position set in the height table 29 is taken out and the distance between the objective lens 12 and the object 8 is moved.

The object 8 is irradiated with a laser beam by the objective lens 12 and the reflected laser is detected by the detector 1.
4, the area measuring unit 21 measures the beam spot area S1 on the object 8 based on the signal from the detector 14, and the beam spot area S1 measured by the Z adjustment processing 24.
Is compared with the designated area S0 to calculate a movement amount ΔZ in the Z direction corresponding to the error. At the drawing start point, the objective lens 12 and the object 8 are moved by the calculated movement amount ΔZ in the Z direction. , The pattern writing is started, and the Z direction is adjusted so that the beam spot area S1 becomes the designated area S0. When the position detection unit 31 is at the branch point of the pattern, the Z coordinate Zi ( i is a branch point)
When the redrawing processing unit 32 starts redrawing from the branch point of the pattern, the stored Z coordinate Zi is set to start drawing the branch pattern.

Therefore, by performing automatic focusing based on the area when the object 8 is irradiated with the laser light,
Automatic focusing can be performed with a very simple and lightweight optical system. In addition, automatic focusing is performed based on the area when the non-photosensitive laser beam is applied to the object 8 to be drawn, stored in the height table 29, and the photosensitive laser beam is used while referring to the table. By drawing the image by using a very simple and lightweight optical system, it is possible to draw a pattern having a uniform line width without increasing an undesired pattern width due to exposure at the time of automatic focusing.

When the branch pattern is drawn, the position (X, Y, Z) of the branch point is stored, and the stored position (X, Y, Z) is used when redrawing from this branch point. ) Can be set to start drawing quickly.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the configuration and operation of an embodiment of the present invention will be sequentially described in detail with reference to FIGS.

FIG. 1 is a block diagram showing one embodiment of the present invention.
In FIG. 1, an optical head 1 irradiates a finely focused beam spot on a drawing target 8 and exposes a photosensitive material on the drawing target 8 to draw a fine pattern. (B).

The X stage 2 and the Y stage 3 are moving mechanisms for moving the object 8 placed on the substrate 9 in the horizontal X and Y directions. The Z stage 4 is a mechanism for arbitrarily moving (adjusting) the distance (distance in the Z direction) between the object 8 placed on the substrate and the objective lens 12.

The stage controller 5 is a mechanism for controlling the movement of the X stage 2, the Y stage 3, and the Z stage 4. The He-Cd laser 6 generates a photosensitive laser beam for exposing the photoresist as the object to be drawn 8.

The light intensity modulator 7 modulates the light intensity of the laser light emitted from the He-Cd laser 6.
The mirror reflects the laser light.

The computer system 20 performs various controls in accordance with a program. Here, a command is issued to the stage controller 5 to control the movement of the X stage 2, the Y stage 3, and the Z stage 4, and to control the movement of the optical head 1. The Z stage 4 is controlled so that the beam spot area S1 on the object 8 detected by the detector 14 becomes equal to the designated area S0 to perform control such as automatic focusing. This computer system 20
Here, the area measurement unit 21, the light intensity modulation unit 22, the light intensity detection unit 23, the Z adjustment processing unit 24, the area-Z conversion unit 2
5 and a control unit 26.

The area measuring section 21 measures a beam spot area S1 on the object 8 based on a signal from the detector 14, and for example, based on a signal from an image pickup device (CCD or the like). The number of pixels having a value of "1" is measured.

The light intensity modulating section 22 modulates the intensity of the output light from the light intensity modulator 7. Light intensity detector 23
Is for detecting the light intensity of the input light to the light intensity detector 20.

The Z adjustment processing section 24 adjusts (moves and controls) the height (ΔZ) of the Z stage 4. Area-Z
The conversion unit 25 calculates the area of the beam spot on the object 8 measured by the area measurement unit 21 (the number of “1” pixels),
When the error from the designated area S0 is equal to or more than the allowable error, the area-ΔZ conversion is performed to make S1 into S0 (see FIG. 4).

The control section 26 performs various general controls. FIG. 2 shows a detailed configuration diagram of the optical head 1 of FIG. In FIG. 2, an optical head 1 irradiates a finely focused beam spot on a drawing target 8 and exposes a photosensitive material on the drawing target 8 to draw a fine pattern. 12, half mirror 13, detector 14
And so on.

The objective lens 12 is for irradiating the laser beam reflected by the half mirror 13 on the object 8 to be drawn narrowly. Here, the object 8 is irradiated with a beam spot having a predetermined area. It squeezes to irradiate.

The half mirror 13 reflects the laser light to be incident on the objective lens 12 or reflects the laser light reflected by the object 8 and incident from the objective lens 12 to a detector 14.
Or the like.

The detector 14 detects a beam spot area and is, for example, a MOS type solid-state image sensor. This MOS solid-state imaging device is a device in which, for example, 244 × 244 minute elements (photo sensors) are regularly and vertically arranged. These minute elements store charges proportional to the incident light, and sequentially transmit them as composite video signals (analog) from signal lines in synchronization with synchronization pulses (horizontal and vertical directions) generated inside the camera. The composite video signal is converted into a digital signal and input to the computer system 20. Then, the area measuring unit 21 measures the area of the beam spot on the drawing target object 8, that is, counts the number of pixels having a bright “1” value to measure the area.

Next, the operation of the configuration of FIGS. 1 and 2 will be described in detail according to the order shown in the flowchart of FIG.
In FIG. 3, A21 moves the object 8 to the position of the optical head 1 using the X and Y stages. This is shown in FIG.
By using the X stage 2 and the Y stage 3, the object 8 is moved to a position where a pattern is drawn by irradiating a laser beam by the optical head 1 with a laser beam.

In A22, laser irradiation starts. this is,
As described on the left side, the light intensity modulator 22 instructs the light intensity modulator 7 to enter the laser beam from the He-Cd laser 6 into the optical head 1 and draw a beam spot reduced by the objective lens 12. The irradiation of the body 8 is started.

A23 inputs the beam spot area S0. This corresponds to the beam spot area S0 on the object 8 to be drawn.
Enter the reference value for. A24 specifies the moving direction of the Z stage. This specifies the moving direction of the Z stage when the detected area S1 is made equal to the area S0 specified by A23, as shown in FIG. 4 described later. For example, FIG.
In the example, when the position of the Z stage is moved from Z1 to Z0, a movement direction in which the area is changed from S1 to S0 is designated.

A29 detects the beam spot area S1. This is shown in FIG.
It is converged by the objective lens 12 and irradiates the object 8 to be drawn,
The reflected laser light is detected by the detector 14 via the objective lens 12 and the half mirror 13. Based on the detected signal, the area measurement unit 21 measures the number of pixels having the light intensity “1”, and takes into account the magnification of the objective lens 12 and the like, and
The area S1 of the upper beam spot is calculated.

A30 compares S0 and S1. | (S
0−S1) / S0 | ≦ E (tolerance), the area S
Since A1 is equal to S0 within the allowable error range, A31, A3
No. 2 proceeds to A33 without moving the Z stage. On the other hand, in the case of | (S0−S1) / S0 |> E (allowable error), the area S1 is larger than the allowable error of S0, so A31
Proceed to.

A31 substitutes S1 for f (S) to obtain ΔZ
Is calculated. This is obtained by substituting into an equation f (S) for obtaining Z1 from the area S1 in FIG.
The difference ΔZ from the reference area S0 to Z0 is calculated.

A32 moves the Z stage to Z0 and sets S
Set to 0. This moves the Z stage 4 by ΔZ calculated by the Z adjustment processing unit 24 in FIG. A33 is X,
This operation is repeated until the first stage reaches the end position. this is,
Since ΔZ was moved at certain X and Y positions and the Z direction was adjusted so that the area on the drawing target body 8 became S0,
The next X and Y positions are repeated, and the adjustment in the Z direction is performed so that the area on the object 8 becomes S0.

As described above, the laser beam is emitted from the objective lens 12.
Thus, adjustment in the Z direction is performed so as to irradiate the drawing target body 8 with the designated area S0 which is appropriately narrowed, and so-called automatic focusing can be performed. In particular, in the present invention, it is possible to perform the automatic focusing by adjusting the distance between the objective lens 12 and the object 8 so that the area of the object 8 to be irradiated by the laser beam spot is S0. Becomes At this time, since the detected area S1 is made equal to the designated reference area S0, the measurement sensitivity is greatly improved as compared with the case where the diameter of the beam spot is detected, and the accuracy and the accuracy are automatically increased. Can focus.

(1) An example of the allowable error E and ΔZ will be described. When the magnification of the objective lens 12 is set to 40 times, when the drawing power is 5 μW, when the beam spot area S0 is set to 100 pixels, the measured beam spot area S1 is: When E = 5%, when S1 = 105, ΔZ = 0. 14 μm ・ S1 = 95, ΔZ = 0.10 μm ・ E = 3% ・ S1 = 103, ΔZ = 0.06 μm ・ S1 = 97, ΔZ = 0.09 μm Here, the minimum resolution of the Z stage 4 is 0.1 μm.
Assuming that m, when E = 5%, ΔZ ≧ 0.1 μm, and the beam spot area can be controlled to S0. On the other hand, when E = 3%, ΔZ <0.1 μm, and it becomes impossible to control the beam spot area to S0. Since E and ΔZ have such a relationship, it is necessary to set E to a certain threshold or more.

(2) Advantages of control by area For example, if the beam diameter is 1 μm and the change in beam diameter is Δrμm, the change in beam area is π (1 + Δr) ² = π (1 + 2Δr + Δr ² ) ≒ π (1+
2Δr) to 2πΔr (Δr ² is about 0.1 μm, and is set to 0 (zero)). Therefore, when the beam diameter is controlled by measuring the area, the sensitivity is improved by 2π ≒ 6.28 times as compared with the case where the beam diameter is directly measured and controlled. Further, when measurement is performed using the area, the detector 14
There is also an advantage that the beam diameter can be detected with high accuracy and high sensitivity even when the number of pixels is small and rough.

FIG. 4 is an explanatory diagram of the area-Z conversion according to the present invention. In FIG. 4, Z = f (S) is Z (distance between the objective lens 12 and the object 8 in the Z direction) by substituting the area (number of pixels) S on the object 8. Calculate
This is a relational expression obtained by measurement in advance.

The beam waist is a state in which the laser beam is narrowed to the minimum by the objective lens 12. The position in the Z direction at the area of the beam waist is Z = 0, and the area of the beam spot at the time of defocus and Z
Is measured (calculated) in advance and determined as shown in the figure.

Thus, as described above, for example, when the beam spot area on the drawing target body 8 is S1, Z1 is obtained, and the difference ΔZ = | Z1 from Z0 when the designated reference area S0 is obtained. −Z0 | can be calculated. And ΔZ
When the Z stage 4 is moved by (= | Z1−Z0 |), the area of the beam spot becomes S0, and automatic focusing in the Z direction can be quickly performed by a single operation. At this time, as described above, since the area S1 is obtained and used for automatic focusing, the detection sensitivity can be greatly improved as compared with the case where the conventional beam spot diameter is detected.
Automatic focusing can be performed accurately and quickly.

Next, the configuration and operation of another embodiment of the present invention will be sequentially described in detail with reference to FIGS. FIG.
Shows a configuration diagram of another embodiment of the present invention. This is because, in addition to the He-Cd laser 6 that emits a photosensitive laser beam, the He-Nd that emits a non-photosensitive laser beam for automatic focusing is used.
an e-laser 61 is newly provided, and a Z adjustment processing unit 27 for previously measuring a distance ΔZ between the non-drawing object 8 and the objective lens 12 using the non-photosensitive laser light in advance, an area-Z conversion unit 28, and This is a configuration when a height table 29 is provided. Here, 2, 3, 4, 5, 6, 7, 21, 22,
23 and 30 are the same as those of the same numbers in FIG. The optical head 1 has the same configuration as that shown in FIG. 1B, and the detector 14 has a non-photosensitive He-Ne
The only difference is that the area of the laser light emitted from the laser 61 on the object 8 to be drawn is detected as a signal.

In FIG. 5, the He—Ne laser 61 is
A non-photosensitive laser beam is emitted to the photoresist, which is the object to be drawn 8, and is for automatically adjusting the distance Z between the objective lens 12 and the object to be drawn 8.

The computer system 20 performs various controls in accordance with a program. Here, the computer system 20 instructs the stage controller 5 to control the movement of the X stage 2, the Y stage 3, and the Z stage 4 and to control the movement of the optical head 1. The area S1 'of the non-photosensitive beam spot on the drawing target 8 detected by the detector 14 becomes the designated area S0' (the non-photosensitive beam spot area S0 'corresponding to the photosensitive beam spot area S0). The Z stage 4 is controlled so as to be equal to each other, and controls such as automatic focusing are performed. The computer system 20 includes an area measurement unit 21, a light intensity modulation unit 22, a light intensity detection unit 23, a Z adjustment processing unit 27, an area-Z conversion unit 28, a height table 29, a control unit 26, and the like. Is what is done.

The area measuring section 21 measures the beam spot area S1 'on the object 8 based on the signal from the detector 14, and also measures the signal from an image pickup device (CCD or the like). At this time, the number of pixels having a value of "1" is measured.

The light intensity modulator 22 modulates the intensity of the output light from the light intensity modulator 7. Light intensity detector 23
Is for detecting the light intensity of the input light to the light intensity detector 30.

The Z-adjustment processing section 27 adjusts (moves and controls) the height (ΔZ) of the Z-stage 4. Here, the object 8 to be drawn is a beam spot of a non-photosensitive laser beam.
The upper area S1 'is measured, and the measured area S0'
Z so as to be equal to (non-photosensitive beam spot area S0 'corresponding to photosensitive beam spot area S0).
The stage 4 is controlled to perform control such as automatic focusing (to be described later with reference to FIGS. 6 and 7).

The area-Z converter 28 calculates the area (number of pixels of “1”) S1 ′ of the non-photosensitive beam spot on the object 8 measured by the area measuring section 21 and the specified area S
When the error from 0 ′ is equal to or larger than the allowable error,
The conversion of the area−ΔZ is performed to make it 0 ′ (see FIG. 8).

The control unit 26 performs various general controls. Next, according to the order shown in the flowchart of FIG.
The overall operation of the configuration in FIG. 5 will be described.

In FIG. 6, B1 moves the object 8 to the position of the optical head 1 using the X and Y stages. In this case, the object 8 is moved to a position where a pattern is drawn by irradiating a laser beam with the optical head 1 using the X stage 2 and the Y stage 3 in FIG.

In B2, the beam spot area S0 is input. In this case, a reference value of the photosensitive beam spot area S0 on the object 8 is input here. B3 specifies the moving direction of the Z stage. This is because, as shown in FIG. 8, which will be described later, the Z stage when the detected area S1 'is equal to the area S0 designated by B2 (the area S0' of the non-photosensitive beam spot corresponding to the area S0). Specify the moving direction of. For example, in the example of FIG. 8, when the position of the Z stage is moved from Z1 to Z0, a movement direction in which the area is changed from S1 to S0 is designated.

In step B4, irradiation with the He-Ne laser 61 is started. This is a non-photosensitive He-
The irradiation of the Ne laser 61 is started. B5 moves the Z stage to Z0 and sets the beam spot area to S0 '. This is to irradiate a non-photosensitive laser beam on the photoresist as the object to be drawn 8 in B4, measure the area S1 ′ at that time, and make the area S1 ′ equal to the designated area S0 ′. Then, the Z stage 4 is moved by ΔZ so as to be Z0 on the curve in FIG. 8 (see FIG. 8).

B6 turns off the He-Ne laser 61. This means that the He-Ne laser irradiation is started in B4 and the automatic adjustment of the distance Z between the object 8 and the objective lens 12 is ended in B5, or ΔZ at each X and Y position is stored in the height table 29. (Setting) has been completed.
-Turn off the Ne laser 61.

At B7, irradiation of the He-Cd laser 6 is started. This is He-Cd that emits a photosensitive laser beam.
The irradiation of the laser 6 is started. B8 starts drawing.
This is a state in which automatic focusing is performed in advance using a non-photosensitive laser beam in B5, or the Z stage 4 is controlled automatically while referring to the value of ΔZ set in the height table 29. Then, a desired pattern is drawn on the object 8 using the photosensitive beam spot.

As described above, the beam spot S0 'specified in advance on the object 8 using the non-photosensitive laser beam
(S0 for photosensitive laser light) is set in the height table 29 to obtain ΔZ, and then automatic focusing is performed with reference to the height table 29 using photosensitive laser light. A desired pattern is always drawn on the drawing object 8 in a state of the beam spot S0. This solves the problem that the starting point, which occurs when performing auto-focusing using a photosensitive laser beam at the start of drawing, is undesirably large, and the adjacent patterns come into contact with each other. (See FIG. 9).

Next, the automatic focusing will be described in detail according to the sequence shown in the flowchart of FIG. In FIG. 7, B11 denotes the object 8 to be drawn using the X and Y stages.
Is moved to the position of the optical head 1.

In B12, the beam spot area S0 is input. B13 specifies the moving direction of the Z stage. B
14 starts irradiation of the He-Ne laser 61. That is, the He-Ne laser 61 starts irradiating the non-photosensitive laser beam.

At B15, the movement of the X and Y stages is started. B16 sets the position of the X and Y stages and the increment of the Z stage in the height table 29.

Step B17 is repeated until the X, Y stage position reaches the end position. These B15, B16, B17
Is a certain X, Y as described in B5 of FIG.
The area S1 'when the non-photosensitive laser beam is irradiated to the object to be drawn 8 at the position and reflected is measured, and the measured area S1' is designated as an area S0 '(the area S0 of the photosensitive laser beam designated as B12). Is calculated using FIG. 8, and the Z stage 4 is moved by ΔZ necessary to make the area equal to the area S0 ′ of the non-photosensitive laser beam corresponding to the above (see FIG. 8). As a result, the area becomes equal to the area S0 'when the object 8 is irradiated with the non-photosensitive laser beam. ΔZ at this time is set and stored in the height table 29 in association with X and Y. Then, this operation is repeated every time the X and Y positions move by a predetermined distance, and the operation is performed on the entire surface of the object 8 to be drawn.

B18 turns off the He-Ne laser 61.
This is because the He-Ne laser 61 is turned off because ΔZ is set and stored in the height table 29 in association with X and Y on the entire surface of the object 8 to be rendered by the non-photosensitive laser beam.

In step B19, irradiation of the He-Cd laser 6 is started. B20 starts drawing. B21 receives the X and Y coordinates from the stage controller 5.

B22 is compared with the height table 29.
These B21 and B22 are used by the stage controller 5 of FIG.
7 receives the X and Y coordinates, the height table 2
The X and Y coordinates set to 9 are compared. If they match, in step B23, the controller extracts the Z from the height table 29, passes it to the stage controller 5, moves the Z stage by the Z, performs automatic focusing, and proceeds to B24. On the other hand, if they do not match, the process proceeds to B24.

In B24, B21 and subsequent steps are repeated until the X and Y stage positions reach the end position. It ends when it reaches the end position. As described above, ΔZ is calculated over the entire surface of the drawing target body 8 using the non-photosensitive laser beam, set in the height table 29 in association with X and Y, and stored. When actually drawing a pattern on the drawing object 8 using a laser beam having different properties, ΔZ corresponding to the X and Y coordinates is taken out by referring to the height table 29 and the movement of the Z stage is controlled, and It is possible to control the spot so as to have the designated area S0.
In particular, there is no need to measure the area S1 at the pattern drawing start position and move the area S0 by ΔZ so as to become the area S0, thereby preventing the pattern from becoming thick at the start point and coming into contact with an adjacent pattern adjacent thereto. it can.

FIG. 8 is a diagram for explaining another operation of the present invention.
FIG. 8A is an explanatory diagram of the area-Z conversion. (A-1) of FIG. 8 shows a case of a He-Ne laser. This uses a He-Ne laser 61 for irradiating a non-photosensitive laser beam, and adjusts the distance in the Z direction between the object 8 and the objective lens 12 under the configuration of FIG. FIG. 9 illustrates a state when automatic focusing is performed. Here, the area S0 ′ is an area for a non-photosensitive laser beam corresponding to the area S0 (area S0 for a photosensitive beam) designated by B2 in FIG. 6 (B12 in FIG. 7). .
The area S1 ′ is an area measured when a non-photosensitive laser beam is applied to the object 8 to be drawn. Therefore, in this case, the Z stage 4 may be moved by ΔZ to change the area S1 ′ to the area S0 ′.

FIG. 8A-2 shows the case of a He-Cd laser. This shows a state in which a desired pattern is drawn on the object to be drawn 8 using the He-Cd laser 6 for irradiating a photosensitive laser beam under the configuration of FIG. Here, the area S0 is B2 in FIG.
Area designated by B12). At S0, the distance from the position of the beam waist (the position when the laser beam is most narrowed down by the objective lens 12 is set to 0) is Z0.

Therefore, when the beam spot area S0 is designated, the area S0 measured by the non-photosensitive beam sport is used.
When it is 1 ′, Z is set by ΔZ so that the area becomes S0 ′.
The movement of the stage 4 is stored in the height table 29, and when the photosensitive laser beam is applied to the object 8 to be drawn, the Z stage is moved by ΔZ to cover the area S0 with the beam spot. Irradiate the drawing body 8,
It is possible to draw.

FIG. 8B shows an example of a height table.
As shown, the height table 29 is a table for measuring and setting a Z increment (ΔZ) with a non-photosensitive beam spot in association with the X position and the Y position. Here, the X position and the Y position are set from the position A (X0, Y0) to the position B (X1, Y
When moving linearly in 1), let the distance between them be ΔL,
Assuming that the moving speed of the stage is V, the control interval Δt is Δt = ΔL / V where ΔL = {(X0−X1) ² + (Y0−Y1) ² }.
^1/2 . Therefore, ΔZ at that time is set and stored in the height table 29 in association with the X position and the Y position at that time for each Δt. Then, when actually writing a pattern using a photosensitive laser beam, ΔZ at this time is taken out from the height table 29 to control the movement of the Z stage 4 and always draw a pattern with a beam spot having an area S0. It is possible to do.

FIG. 9 shows an example of a pattern by a drawing method. Here, the right direction indicates the relative traveling direction of the optical head 1 with respect to the object 8 to be drawn. FIG. 9A shows an example in which drawing is started after focusing at the drawing start point. In this case, the beam pattern expands as shown in the drawing by performing automatic focusing at the drawing start point.
After the focusing is completed, it is drawn in the right direction with the same line width.

FIG. 9B shows an example in which automatic focusing is performed using a non-photosensitive beam spot, ΔZ at that time is set in the height table 29, and drawing is performed using this. . This is the case of the other embodiment of the present invention described with reference to FIGS. 6 to 8, and it is possible to always draw a pattern with the same line width from the start point.

FIG. 9 (c) shows a state in which a pattern is approached at the drawing start point when a close pattern is drawn by the drawing method of FIG. 9 (a). (D) of FIG.
FIG. 7B shows a state in which a pattern is drawn with the same line width without contacting at the drawing start point when drawing a close pattern by the drawing method of FIG. As described above, according to the other embodiment of the present invention described with reference to FIGS. 6 to 8, it is possible to draw a pattern with the same line width from the drawing start point, and it is possible to particularly prevent the adjacent pattern from coming into contact.

Next, the configuration and operation of another embodiment of the present invention will be described in detail with reference to FIGS. FIG.
Shows a configuration diagram of another embodiment of the present invention. This is a configuration in which a position detection unit 31 and a re-drawing processing unit 32 are newly provided when drawing a branch pattern using the He-Cd laser 6 that emits a photosensitive laser beam. Here, 1, 2, 3, 4, 5, 6, 7, 20, 21, 22,
23, 24, and 25 are the same as those in FIG.

In FIG. 10, a position detecting section 31 detects a branch point of the pattern and stores the position (X, Y, Z). For example, a position of the beam spot at the branch point of the bent pattern 1 described later is detected. The position (X, Y, Z) when ΔZ is adjusted so that the area S1 becomes equal to the designated area S0 is stored. The position (X, Y, Z) of this branch point is stored, and the position (X, Y, Z) is immediately set when pattern drawing is started from the branch point.
And drawing can be started without performing focusing (see FIGS. 11 and 12).

The re-drawing processing unit 32 performs re-drawing from the branch point of the pattern. The re-drawing processing unit 32 sets the position (X, Y, Z) stored at the later-described branch point of the bent pattern 1 for re-drawing. (FIGS. 11 and 12)
reference).

Next, the operation of the configuration of FIG. 10 will be described in detail according to the order shown in the flowchart of FIG. FIG.
, C1 turns on the laser. This is shown in FIG.
By using the X stage 2 and the Y stage 3, the object 8 is moved to a position where a pattern is drawn by irradiating a laser beam with the optical head 1.

C2 is adjusted so as to have a predetermined area at the drawing start point. This is because, for example, the area S1 at the position of the drawing start point a of the bent pattern 1 in FIG. 12A is set to the predetermined area S0 so that the area S1 of the beam spot on the object 8 becomes equal to the predetermined area S0. Z to be equal to
Adjust stage 4.

C3 performs pattern drawing and adjustment of a predetermined area. This is a → b → c → as described on the right.
The pattern is drawn along the bent pattern 1 of d, and the beam spot area S1 is adjusted to be equal to the predetermined area S0.

It is determined whether C4 is a branch point. This is C3
When the pattern is drawn and the predetermined area is adjusted, it is determined whether the pattern is a branch point. For example, it is determined whether it is the branch point b in FIG. In the case of YES, Zb (the value of Z at point b) is stored here as the value in the Z direction at that time. NO
In the case of, the process proceeds to C6.

At C6, it is determined whether the drawing is completed. This is done by, for example, starting to draw the bent pattern 1 in FIG. 12A, drawing a → b → c → d, and determining whether drawing is completed to d. If YES, proceed to C7. If NO, the process returns to C3.

C7 turns off the laser. this is,
Since the drawing is completed with YES in C6, the He-Cd
The irradiation of the laser 6 is turned off. C8 moves the head to the drawing start point and the Zb position. This is, for example, FIG.
As shown in FIG. 2 (B), after drawing up to point d, He-
The irradiation of the Cd laser 6 is turned off and the optical head is moved to the drawing start point of the branch point b and moved to the stored Zb position.

C9 turns on the laser. Thus, for example, the laser is turned on at the point b in FIG. C10 performs pattern drawing and adjustment of a predetermined area. This is, as described on the right, b → e →
The pattern is drawn along the bent pattern 2 of f, and the beam spot area S1 is adjusted to be equal to the predetermined area S0.

Step C11 decides whether or not the drawing is completed. this is,
For example, drawing of the bent pattern 2 in FIG. 12C is started, drawing is performed in the order of b → e → f, and it is determined whether the drawing is completed up to f. If YES, the process ends. In the case of NO,
Return to C10 and repeat C10 until f is reached.

As described above, for example, the bent pattern having the branch point shown in FIG. 12 is drawn as a → b → c → d and the predetermined area is adjusted, and the position Zi in the Z direction at the branch point is stored. The position Zi stored at the start of drawing the next bent pattern from the branch point is set, and pattern drawing is started immediately. Thereby, when drawing a pattern having a branch point, for example, a Y branch pattern,
It is not necessary to perform focusing at a branch point, and it is possible to draw quickly.

FIG. 12 is a diagram for explaining another operation of the present invention. This is an explanatory diagram when adjusting the Z direction when drawing a branch pattern and storing Zi at a branch point.
FIG. 12A shows a bent pattern 1 (laser O).
N). Here, the bent pattern 1 includes a pattern 1-1, a pattern 1-2, and a pattern 1 as shown in the figure.
-3, and is a pattern to be drawn such as drawing start point a → b → c → d. At the time of drawing, drawing is performed while adjusting the position Zi in the Z direction such that the area S1 of the beam spot at the drawing start point a becomes equal to the predetermined area S0. Then, the position Zb of the branch point, here, the point b in the Z direction
Is stored.

FIG. 12B shows the movement of the optical head (laser OFF). This is because, after the drawing of the bent pattern 1 in the order of a → b → c → d in FIG.
The laser is turned off to move to the branch point b, and is adjusted to the stored position Zb in the Z direction. This allows
It is not necessary to adjust the area S1 of the beam spot at the point b to be equal to the predetermined area S0, and it is possible to immediately start redrawing.

FIG. 12C shows the bent pattern 2
(Laser ON). This is because the optical head is moved to the branch point b in FIG.
Is drawn in the order of b → e → f. At this time, the bent pattern 2 is composed of a pattern 2-1 and a pattern 2-2, and is drawn in a drawing start point b → e → f.

FIG. 12D shows an example of a branch interference pattern. Regarding this branch interference pattern, the branch point b ′,
The positions Zb ′ and Zb ″ (or only the position Zb ′) in the Z direction at b ″ (or only the branch point b ′) are stored, and the position in the Z direction when redrawing is started from the branch point By setting Zb ′ and Zb ″ (or position Zb ′), focusing at the branch point becomes unnecessary,
It is possible to start drawing at high speed.

[0091]

As described above, according to the present invention,
Automatic focusing is performed based on the area when the object to be drawn 8 is irradiated with the laser light, and the image is automatically focused based on the area when the non-photosensitive laser light is applied to the object 8 to be drawn. Since the pattern is drawn by using a photosensitive laser beam after the alignment, the pattern can be drawn with a very simple and lightweight optical system, and an undesired pattern width due to exposure at the time of auto focus , And a pattern having a uniform line width can be drawn. In addition, the position (X, Y, Z) of the branch point is stored when drawing the branch pattern, and the position (X, Y, Z) stored when redrawing from the branch point is set. By starting the drawing, the drawing can be started quickly without the need for focusing at the branch point. Accordingly, (1) it is possible to control the laser beam diameter having a sufficient function by using a very simple configuration without applying a heavy load to the Z stage.

(2) By setting and storing in advance in the height table 29 the ΔZ when focusing is performed using a non-photosensitive laser beam, the laser beam is used for patterning the photosensitive laser beam. Since focusing is not required and the line width does not increase at the position where the drawing starts, it is possible to easily draw a pattern such as a directional coupler in which lines are close to each other.

(3) When redrawing from a branch point of a pattern having a Y-branch, focusing can be made unnecessary and rapid drawing can be performed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of one embodiment of the present invention.

FIG. 2 is a configuration diagram of an optical head of the present invention.

FIG. 3 is a flowchart illustrating the operation of the present invention.

FIG. 4 is an explanatory diagram of area-Z conversion according to the present invention.

FIG. 5 is a configuration diagram of another embodiment of the present invention.

FIG. 6 is a flowchart (part 1) for explaining another operation of the present invention.

FIG. 7 is a flowchart (part 2) for explaining another operation of the present invention.

FIG. 8 is another operation explanatory diagram of the present invention.

FIG. 9 is a pattern example according to a drawing method.

FIG. 10 is a configuration diagram of another embodiment of the present invention.

FIG. 11 is a flowchart illustrating another operation of the present invention.

FIG. 12 is a diagram illustrating another operation of the present invention.

[Explanation of symbols]

 1: Optical head 2: X stage 3: Y stage 4: Z stage 5: Stage controller 6: He-Cd laser 61: He-Ne laser 7: Light intensity modulator 20: Computer system 21: Area measuring unit 22: Light Intensity modulation unit 23: Light intensity detection unit 24, 27: Z adjustment processing unit 25, 28: Area-Z conversion unit 26: Control unit 29: Height table 30: Light intensity detector 31: Position detection unit 32: Redraw Processing unit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-118712 (JP, A) JP-A-2-94118 (JP, A) JP-A-2-3033693 (JP, A) JP-A-2- 168295 (JP, A) Hira 2-117719 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03F ^7/ 20-7/24 G03F 9/00-9/02 H01L 21/027

Claims (2)

(57) [Claims] In a laser beam control method for controlling focusing of a laser beam, an object to be drawn (8) is irradiated with a non-photosensitive laser beam through an objective lens (12), and the reflected laser is irradiated.
A detector (14) in which a large number of microelements are arranged vertically and horizontally on a part to be radiated, and respective signals from each microelement of the detector (14)
Of which the laser beam is illuminated or more than a predetermined brightness
The object to be drawn (8) is counted by counting the total number of signals having the same value.
The area measuring unit (21) for measuring the non-photosensitive beam spot area S1 'above compares the measured beam spot area S1' with the designated area S0 'and corresponds to the error. A Z-adjustment processing unit (27) for calculating a movement amount △ Z in the Z-direction. At the laser drawing start position and the like, the objective lens (12) and the object to be drawn (8) are moved by the calculated movement amount △ Z. A laser beam control method, wherein the laser beam is moved by a distance. 2. A laser beam control method for controlling the focusing of the laser beam, the laser beam of non-photosensitive via the objective lens (12) is irradiated onto the drawing object (8), laser GaTeru which has been reflected
A detector (14) in which a large number of microelements are arranged vertically and horizontally on a part to be radiated, and respective signals from each microelement of the detector (14)
Of which the laser beam is illuminated or more than a predetermined brightness
The object to be drawn (8) is counted by counting the total number of signals having the same value.
The area measuring unit (21) for measuring the non-photosensitive beam spot area S1 'above compares the measured beam spot area S1' with the designated area S0 'and corresponds to the error. A Z adjustment processing unit (27) for calculating a movement amount 移動 Z in the Z direction; and the Z adjustment processing unit (27) calculating the movement amount △ Z for a predetermined position of the whole object to be drawn (8). And a height table (29) to be set. When a pattern is drawn on the object (8) by irradiating a photosensitive laser beam, a position corresponding to the position set on the height table (29) is provided. Take out the Z and remove the objective lens (1
2) A laser beam control method characterized in that the distance between the object and the object to be drawn (8) is adjusted.