JP3525177B2 - Material processing method using X-ray - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention irradiates an X-ray through a X-ray mask on a material that can be processed at a depth corresponding to the amount of X-ray irradiation, thereby processing each part of the material at a variable depth. The present invention relates to a method of processing a material using X-rays.

[0002]

2. Description of the Related Art As the integration of electronics and mechanical parts such as information and communication equipment and micromachines progresses, not only electronic parts but also mechanical parts are required to be minute and highly precise. Conventionally, a method called LIGA is known as a method suitable for such highly accurate processing. LIGA (Lithographie Galvanoformung Abformun
g) is a method proposed in Germany, whose name derives from the German acronyms for lithography, electroplating and molding.

In this LIGA, first, as shown in FIG. 6A, a resist material 2 made of PMMA (polymethylmethacrylate) or the like is formed on a substrate 1 made of metal or the like, and an X-ray transmission layer is then formed. X-ray absorbing layer 3 having a desired shape on 3a
The resist material 2 is irradiated with X-rays from a synchrotron light source (not shown) or the like through the X-ray mask 3 on which b is formed.

As shown in FIG. 7A with the thickness of the X-ray mask 3, the X-ray absorbing layer 3 is provided on the back surface side of the X-ray transmitting layer 3a.
X-rays are absorbed and not transmitted in the region where b is formed, but X-rays are transmitted in the region where the X-ray absorption layer 3b is not formed. As a result, in the exposed region of the resist material 2 which is irradiated with X-rays. The molecular chain is cut and the molecular weight is reduced.

Therefore, when the resist material 2 is developed with a predetermined developing solution after the exposure is completed, the resist material 2 is removed in the exposed area to form the concave portion 2a. The depth of the concave portion 2a, that is, the processing depth is determined by the cumulative dose of X-rays.
Specifically, in the case of the resist material 2 made of PMMA, as shown in (b) in FIG. 7, when the required processing depth is relatively small, the processing depth is approximately proportional to the cumulative irradiation dose, As the required processing depth increases, the rate of increase in the processing depth corresponding to the cumulative irradiation dose decreases.

Returning to FIG. 6, when the X-ray mask 3 shown in FIG. 6A is used to irradiate a sufficient amount of X-rays to remove the entire resist material 2 in the thickness direction, As shown in b), the resist material 2 is formed in the region where the X-ray absorbing layer 3b is formed.
The cumulative dose of X-rays to the X-ray becomes approximately 0%, while the cumulative dose of X-rays in the region where the X-ray absorbing layer 3b is not formed is approximately 1%.
It becomes 00%.

As a result, as shown in FIG. 6 (c), X
The resist material 2 remains almost entirely in the region where the X-ray absorbing layer 3b is formed, while the resist material 2 is removed almost entirely in the region where the X-ray absorbing layer 3b is not formed. The cumulative dose of X-rays is a value calculated on the assumption that the dose required to completely remove the resist material 2 in the thickness direction is 100%.

After partially removing the resist material 2 as described above, although not shown, the gap between the remaining resist material 2 is filled with a metal such as Ni by an electroplating method, and then the resist material 2 is removed. As a result, a metal structure having a predetermined uneven shape can be obtained.

By using this metal structure as a mold, a micropart made of plastic or ceramic can be produced,
The metal structure itself can be used as a micro component. According to the above-mentioned LIGA, the aspect ratio (height dimension / width dimension) of the residual resist material 2 in FIG. 6C, that is, the aspect ratio of the final product may be set to several tens to 100 or more. it can.

[0010]

However, in the above method, the remaining resist material 2 in FIG. 6 (c), that is, the restriction that only uniform processing is possible in the height direction (processing depth direction) of the final product. There is. That is, the horizontal cross-sectional area of the residual resist material 2 (cross-sectional area parallel to the surface of the substrate 1) is constant regardless of the height position of the resist material 2, but this is the X-ray integration in FIG. The dose distribution is about 0% at the position where the X-ray absorption layer 3b exists, and about 100 at the position where it does not exist.
This is because there is no intermediate value.

Therefore, as shown in FIG. 8A, for example,
If the X-ray mask 3 having the circular X-ray absorption layer 3b is moved relative to the resist material 2 and the resist material 2 is irradiated with X-rays through the X-ray mask 3, the same effect can be obtained. As shown in (c) in the figure, for example, the resist material 2 after development can have a truncated cone shape.

This is because, for example, as shown by an arrow C in FIG. 8A, the relative movement path of one corner point 3c of the X-ray mask 3 is absorbed by the X-ray mask 3 in the horizontal plane. By continuously moving at a constant angular velocity so as to draw a circle having a radius smaller than the radius of the layer 3b, as shown in (b) of FIG. This is because an area in which the cumulative X-ray irradiation dose continuously changes is provided between the area and the area irradiated with X-rays.

However, the X-ray mask 3 as shown in FIG.
In the processing method of exposing while moving the, it is relatively easy to process a simple three-dimensional shape such as a truncated cone, but it is not possible to process a three-dimensional shape including an asymmetrical three-dimensional shape or an arbitrary curved surface shape. There was a constraint that it was difficult.

[0014]

In order to solve the above-mentioned problems, the present invention is a method of processing a material using X-rays capable of easily processing a three-dimensional shape including left-right asymmetry and an arbitrary curved surface shape.
The purpose is to provide the law . Therefore, in the method of processing a material using X-rays according to claim 1 of the present invention, the X-ray is processed while the material that can be processed at a depth corresponding to the dose of X-rays and the X-ray mask are relatively moved. X through the mask on the above material
In the method of processing each part of the material with variable depth by irradiating with a ray, the length of the X-ray mask in the relative movement direction corresponds to the thickness of the cross-sectional shape of the processed material in the predetermined direction. An X-ray mask having an X-ray absorption layer having the above-described shape is arranged at a predetermined distance from the surface of the material, and the X-ray mask is relatively moved in a direction orthogonal to a cross section of the material in a predetermined direction. While passing through the X-ray mask, X
The material is characterized in that the material is processed by irradiating a line.

According to a second aspect of the present invention, there is provided a method of processing a material using X-rays according to the first aspect, wherein the X-ray mask is relatively moved.
Using one or a plurality of X-ray masks each having an X-ray absorption layer whose length in the moving direction corresponds to the thickness of the cross-sectional shape of the material after processing in a plurality of directions, and is orthogonal to the individual cross-sections of the material. The X-ray mask is characterized in that the material is irradiated with X-rays through the X-ray mask while relatively moving the corresponding X-ray masks in respective directions.

Here, one or a plurality of X-ray masks are used because the same X-ray mask can be used for a plurality of directions when the materials have the same cross-sectional shapes in a plurality of directions. When the cross-sectional shapes in different directions are different from each other, it is meant that X-ray masks having different shapes of X-ray absorbing layers can be used in each direction.

A method of processing a material using X-rays according to a third aspect is the method according to the first or second aspect, wherein after the material is previously processed, a desired position of the processed material and a desired position of the X-ray mask. And the X-ray mask and the material are moved relative to each other, and the X-ray mask and the X-ray mask are moved relative to each other.
It is characterized in that the material is processed by irradiating the material with X-rays through a line mask.

[0018]

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1A, a processing device using X-rays includes an X-ray mask 3 fixedly arranged at a predetermined position and a resist material 2 (material) such as PMMA with a substrate 1 made of metal or the like. And a drive unit (not shown) that reciprocates the table 4 with respect to the X-ray mask 3 at a constant speed in the Y-axis direction. Each of these elements is a vacuum or He or the like. It is placed in an exposure chamber (not shown) filled with gas (about 1 atm).

The processing apparatus has an X-ray irradiation unit (not shown) including a synchrotron radiation device and the like outside the exposure chamber, and X-rays are incident on the inside of the exposure chamber from the X-ray irradiation unit to generate X-rays. The resist material 2 is irradiated through the mask 3. In the figure, X0, Y0, and Z0 respectively indicate the sizes of the resist material 2 in the X-axis, Y-axis, and Z-axis directions, and as is clear from (a) in FIG.
The size of the line mask 3 in the X-axis and Y-axis directions is the resist material 2
Are set to be equal to the sizes X0 and Y0 in the X-axis and Y-axis directions, respectively.

The X-rays from the X-ray irradiator are X-ray masks 3.
Is irradiated only in the area where the X-ray mask is arranged, and when the resist material 2 is out of the area where it overlaps with the X-ray mask 3 as the table 4 moves, X-rays are present on the resist material 2 in the area where it does not overlap with the X-ray mask 3. The line is not illuminated.

For example, when it is desired to process the resist material 2 into a shape as shown in FIG. 1C, as shown in FIG. 1A, the X-ray mask 3 has a cross section of the resist material 2 after the processing. An X-ray absorption layer 3b (shown with hatching for convenience) having a shape substantially the same as the shape is formed in advance.

As shown in FIG. 3, in the present embodiment,
While reciprocating the table 4 in the Y-axis direction at a constant speed (see the arrow M), the X-ray mask 3 is used to move the X-ray on the resist material 2.
Expose the line.

In this case, the table 4 has an I position in which the front end position 2a of the resist material 2 in the Y-axis direction is located in front of the rear end position 3d in the Y-axis direction of the X-ray mask 3 and the Y position of the resist material 2. The rear end position 2b in the axial direction is moved to the II position passing through the front end position 3c in the Y-axis direction of the X-ray mask 3. That is, the entire region of the resist material 2 passes under the X-ray mask 3 during one forward movement (movement to the right in FIG. 3) or backward movement (movement to the left in FIG. 3) of the table 4. Set the movement range.

As described above, when the resist material 2 is irradiated with X-rays while moving the table 4 in the Y-axis direction at a constant speed, the cumulative X-ray irradiation dose in each part of the resist material 2 in the X-axis direction is shown in FIG. The distribution is as shown by the curve f'in the middle (b).

That is, in FIG. 2A, the curved shape formed by the contour of the X-ray absorbing layer 3b in the X-ray mask 3 (the contour of the portion not in contact with the rear end 3d) is represented by a predetermined function f. Then, the curve f ′ in FIG.
The polarity (+) is inverted to (-), and the function after inversion is further translated from the (-) side to the (+) side.

More specifically, in FIG. 2 (a), the function f at each point where the X coordinate is X1, X2 and X3.
The values (Y coordinates) of Y are Y1, Y2, and Y3, respectively. Considering the position where the X coordinate on the resist material 2 is X1,
The length of the X-ray mask 3 as a whole in the Y-axis direction is Y0, whereas the length of the X-ray absorbing layer 3b is Y1, and the moving speed of the table 4 is constant. The probability that X-rays are shielded during the period is Y1 / Y0, and conversely the X coordinate is X1.
The probability that the X-ray will be irradiated to the position (the actual X-ray irradiation time to the position where the X coordinate is X1 / total irradiation time) is (Y0-Y1).
/ Y0 = α1.

Similarly, the probability that X-rays will be irradiated to the position of X2 on the resist material 2 is (Y0-Y2) / Y0 = α.
It becomes 2. Further, at the position where the X coordinate is X3, Y3 = Y0, and the X-ray is always shielded, so that the probability of being irradiated with the X-ray is 0.

Therefore, as described above, the curve f'indicating the change in the X-ray integrated dose in the X-axis direction is obtained by vertically inverting the function f. When the X-coordinates on the resist material 2 are the same, the X-ray integrated irradiation dose is constant regardless of the Y-coordinate, that is, the position of the resist material 2 in the Y-axis direction. This is because, in FIG. 3, the entire region of the resist material 2 in the Y-axis direction passes below the entire region of the X-ray mask 3 in the Y-axis direction during one forward or backward movement of the table 4.

As a result, after exposure while moving the table 4, the resist was developed by using an appropriate developing solution such as a mixed aqueous solution of 2- (2-butoxyethoxy) ethanol, morpholine and 2-aminoethanol. The material 2 is processed into a shape as shown in FIG. That is, the cross-sectional shape of the resist material 2 on the XZ plane is constant regardless of the Y coordinate and becomes as shown in FIG. 2B, and the X-ray absorption in the XY plane of the X-ray mask 3 of FIG. Layer 3b
Is mapped onto the XZ plane of the resist material 2.

However, the size Y0 of the X-ray mask 3 in the Y-axis direction
And the size Z0 of the resist material 2 in the Z-axis direction are different from each other, the cross-sectional shape of the resist material 2 in the XZ plane is a state in which the shape of the X-ray absorbing layer 3b is enlarged or reduced by Z0 / Y0 times in the vertical direction (X-axis). The direction is the same size).

Conversely, when the X-ray mask 3 is created,
Based on the Z-axis size Z0 (thickness) of the resist material 2 and the Y-axis size Y0 of the X-ray mask 3, the cross-sectional shape of the processed resist material 2 is enlarged or reduced Y0 / Z0 times in the vertical direction. The shape (the same size in the X-axis direction) needs to be the shape of the X-ray absorption layer 3b.

In the present specification, the shape obtained by enlarging or reducing the cross-sectional shape of the processed resist material 2 in the vertical direction (equal magnification in the X-axis direction) is the shape of the X-ray absorbing layer 3b as described above. Including such cases, the cross-sectional shape of the processed resist material 2 and the shape of the X-ray absorbing layer 3b are expressed as being substantially equal.

As shown in FIG. 7B, when PMMA is used as the resist material 2, the processing depth is several hundreds.
In the range of about μm or less, the cumulative dose of X-rays and the processing depth are substantially proportional to each other.
If the thickness Z0 is less than about several 100 μm, the shape of the X-ray absorbing layer 3b of the X-ray mask 3 need only be substantially equal to the cross-sectional shape of the processed resist material 2 as described above.

On the other hand, when the thickness Z0 of the resist material 2 exceeds several hundreds of μm, as is apparent from FIG. 7B, the cumulative X-ray dose and the working depth are not proportional. It is necessary to make the shape of the X-ray absorbing layer 3b different from the cross-sectional shape of the resist material 2 after processing according to the processing depth. Specifically, in FIG. 2A, the shape of the curve f may be shifted downward in a region having a large working depth, that is, a region having a small Y coordinate.

As described above, in the present embodiment, the shape of the X-ray absorbing layer 3b in the X-ray mask 3 can be substantially transferred to the cross-sectional shape of the processed resist material 2, so that the cross-sectional shape of the resist material 2 can be changed to the left and right. An asymmetrical shape or an arbitrary curved shape can be easily performed.

Next, another embodiment of the present invention will be described. In the above-described embodiment, the X-ray mask 3 is exposed and developed while moving the resist material 2 in only one direction at a constant speed, but one or a plurality of resist materials 2 may be moved while moving in a plurality of directions. By exposing using the X-ray mask 3, the resist material 2 can be processed into a more complicated three-dimensional shape.

For example, when the X-ray mask 3 having the X-ray absorbing layer 3b having the shape as shown in FIG. 4A is exposed while being relatively moved in one direction of the resist material 2 as in the above, and developed, As a result of the shape of the X-ray absorbing layer 3b being transferred to the resist material 2, the resist material 2 is processed into a shape as shown in FIG.

Then, the resist material 2 shown in FIG.
The resist material 2 is rotated by 0 °, and the same X-ray mask 3 as described above is again moved in the same direction as the rotated resist material 2 in the same direction as described above.
It is processed into a shape as shown in.

In this case, the resist material 2 at the far right end of the substantially square pyramid-shaped resist materials 2 arranged in the vertical and horizontal directions on the substrate 1 is the vertical surface parallel to the X axis including the vertex 2c and the above. The cross-sectional shape of each cross section cut along a vertical plane parallel to the Y axis including the apex 2c is substantially the same as the shape of the X-ray absorption layer 3b.

In the above embodiment, the same X-ray mask 3 is exposed and developed while being moved relative to the resist material 2 in two directions orthogonal to each other.
Alternatively, two X-ray masks 3 having different shapes of the X-ray absorbing layer 3b may be used to perform exposure in two directions orthogonal to each other. In that case, a cross section of the resist material 2 after processing in two directions. The shapes will be different from each other.

FIG. 5 shows still another embodiment. As shown in (a) in the figure, predetermined processing is performed on the resist material 2 in advance (here, a plurality of holes 2d penetrating in the thickness direction of the resist material 2 are formed at predetermined intervals W in the vertical and horizontal directions).
Then, the X-ray mask 3 having the X-ray absorption layer 3b having the shape shown in FIG.

The distance W between the repetitive patterns in the X-ray absorbing layer 3b is the distance W between the holes 2d in the resist material 2.
And the center line L1 of the repeating pattern of the X-ray absorbing layer 3b and the center connecting line L1 of the centers of the adjacent holes 2d are opposed to each other.
Position and. Then, the connecting line L1 and the center line L
When the resist material 2 is exposed through the X-ray mask 3 while the X-ray mask 3 is moved in the direction of the center line L2 while the value 2 and 3 are matched, the resist material 2 has the shape shown in FIG. Become.

After that, the resist material 2 shown in FIG.
After rotating by 0 °, the connecting line at the center of the hole 2d adjacent to the center line L2 of the repetitive pattern of the X-ray absorbing layer 3b (however, is orthogonal to the connecting line L1 in FIG. 5A). (D) in FIG. 5, and the X-ray mask 3 is exposed to light through the X-ray mask 3 while being moved in the direction of the center line L2, the shape becomes as shown in FIG. That is, a nozzle shape is formed in which the hole 2d is opened in the tip end surface 2e of the protrusion that gradually narrows upward.

The materials processed by the processing techniques according to the embodiments shown in FIGS. 1 to 5 are used in the fields of information communication and electronics, such as printer nozzles and semiconductor inspection probe tips. In the optical field, Fresnel lenses, microlens arrays,
In the medical and biometric fields such as diffraction gratings, spectral gratings, filters, antireflection plates, etc., it can be used for a wide range of applications such as biomedical electrode needles, biofluid collection needles, drug injection needles, and the like.

[0046]

According to the method of processing a material using X-rays of the first aspect of the present invention, the length of the X-ray mask in the direction of relative movement is set.
An X-ray mask having an X-ray absorption layer having a shape corresponding to the thickness of the cross-sectional shape of the processed material in a predetermined direction is arranged at a predetermined distance from the surface of the material. The material is processed by irradiating the material with X-rays through the X-ray mask while relatively moving the material in a direction orthogonal to a cross section of the material in a predetermined direction. When irradiating the material with X-rays while moving the mask in the direction orthogonal to the cross section, the larger the proportion of the X-ray absorption amount in the moving direction of the X-ray mask, the smaller the amount of X-ray irradiation to the material. As a result, the working depth of the material is reduced.

Therefore, the cross-sectional shape of the predetermined cross section after processing is substantially similar to the shape of the X-ray absorbing layer in the X-ray mask. As described above, according to the present invention, the desired cross-sectional shape can be processed simply by determining the shape of the X-ray absorption layer in the X-ray mask in accordance with the cross-sectional shape of the processed material. A three-dimensional shape including a curved cross-sectional shape can be easily processed.

According to a second aspect of the present invention, there is provided a method for processing a material using X-rays, wherein the first method is applied to a plurality of directions of the material. When the X-ray mask is processed by irradiating X-rays while moving the X-ray mask in one direction as described in claim 1, the cross-sectional shape of the material after processing becomes constant in the moving direction of the X-ray mask. By performing such processing in multiple directions of the material, it becomes possible to create a more complicated three-dimensional structure.

A method for processing a material using X-rays according to a third aspect is the method according to the first or second aspect, wherein after the material has been processed in advance, a desired position of the processed material and a desired position of the X-ray mask. And the X-ray mask and the material are moved relative to each other, and the X-ray mask and the X-ray mask are moved relative to each other.
Since the material is processed by irradiating the material with X-rays through a line mask, the material can be processed into a more complicated three-dimensional shape.

[0050]

[0051]

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a relationship between a processing apparatus using X-rays, an integrated X-ray irradiation dose, and a shape of a resist material after processing according to an embodiment of the present invention.

FIG. 2 is an explanatory view showing the relationship between the shape of an X-ray mask and the sectional shape of a resist material after processing in the above processing apparatus.

FIG. 3 is an explanatory view showing a manner in which a resist material is moved relative to an X-ray mask of the processing apparatus.

FIG. 4 is an explanatory diagram showing a state in which an X-ray mask is exposed and processed while being sequentially moved in two directions according to another embodiment of the present invention.

FIG. 5 is an explanatory view showing a state in which an X-ray mask is exposed and processed while being sequentially moved in two directions according to still another embodiment of the present invention.

FIG. 6 is an explanatory diagram showing a relationship between a conventional processing apparatus using X-rays, an integrated X-ray irradiation dose, and a shape of a resist material after processing.

FIG. 7 is an explanatory diagram showing the relationship between the cumulative X-ray irradiation dose and the processing depth of a resist material.

FIG. 8 is an explanatory view showing the relationship between another conventional processing apparatus using X-rays, the cumulative X-ray irradiation dose, and the shape of the resist material after processing.

[Explanation of symbols]

2 Resist material (material) 3 X-ray mask 3b X-ray absorption layer

Claims (3)

(57) [Claims] 1. An X-ray is irradiated onto the material through the X-ray mask while relatively moving a material that can be processed at a depth corresponding to the X-ray irradiation dose and the X-ray mask,
A method of processing each part of a material with a variable depth, wherein the length of the X-ray mask in the direction of relative movement corresponds to the thickness of the cross-sectional shape of the material after processing in a predetermined direction. The X-ray mask having the above is arranged at a predetermined distance from the surface of the material, and the X-ray mask is moved through the X-ray mask while relatively moving the X-ray mask in the direction orthogonal to the cross section of the material in the predetermined direction. A method of processing a material using X-rays, characterized in that the material is processed by irradiating the material with X-rays. 2. One or a plurality of X-ray absorbing layers each having an X-ray absorption layer whose length in the direction of relative movement of the X-ray mask corresponds to the thickness of the cross-sectional shape of the processed material in a plurality of directions. The material is irradiated with X-rays through the X-ray mask while relatively moving the corresponding X-ray masks in a direction orthogonal to the individual cross sections of the material using the X-ray mask. 1. A method of processing a material using X-rays according to 1. 3. After the material has been processed in advance, the desired position of the processed material and the desired position of the X-ray mask are positioned so as to face each other, and then the X-ray mask and the material are relatively moved. The method for processing a material using X-rays according to claim 1 or 2, wherein the material is processed by irradiating the material with X-rays through the X-ray mask .