JPH0428710Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a laser processing device that can perform fine processing using a laser beam while observing the processing location of a workpiece with a microscope.

[Prior Art] The laser processing apparatus of the above type is used for photomask repair (mask repair) in the semiconductor manufacturing process;
It was developed for microfabrication purposes such as resistance value adjustment (resistance trimming), in which a part of the resistor in a hybrid IC or resistance module is cut to adjust the resistance value to a set value. Figure 4 shows a conventional example. This is what is shown.

In FIG. 4, reference numeral 1 denotes a microscope section, and this microscope section 1 constitutes a so-called infinite barrel type microscope, and the objective lens 1b attached to the lower end of the barrel 1a is located above the objective lens 1b in the figure. A lens 1c that converts light from a focal point outside the objective lens 1b into parallel light, and a lens 1d that converts the parallel light into convergent light again are provided. Further, this microscope section 1 is provided with a half mirror 1e above the lens 1d so as to form an angle of approximately 45 degrees with the optical axis of these lenses, and furthermore, a half mirror 1e is provided at the right eyepiece section of the half mirror 1e in the figure. 1g is provided.

Further, the upper end of the lens barrel 1a is open, and a beam section shaper 2 is coupled to this open upper end. This beam section shaper 2
The main body 2a has a substantially same cylindrical shape as the lens barrel 1a and is placed on the upper end of the lens barrel 1a, and the main body 2a is arranged perpendicularly to the central axis of the main body 2a within the main body 2a. The light shielding plate 2b has an opening 2c in its center. Although not shown, the opening 2c is configured so that its opening shape can be changed arbitrarily.

Furthermore, an optical coupler 3 is coupled to the upper end of the beam section shaper 2. This optical coupler 3
A main body part 3a having a substantially same cylindrical shape as the main body part 2a of the beam cross-section shaper 2, and a main body part 3a.
A half mirror 3b located inside and arranged at an angle of 45° with the central axis of the main body portion 3a, a collimator portion 3c provided on the left side of the half mirror 3b in the figure, and the half mirror 3b. It is composed of a correction plate 3d provided above in the figure,
guiding the laser beam _r1 emitted from the laser device 4a of the laser oscillation section 4 coupled to the upper end of the main body section 3a in the figure and the light emitted from the light source 5 to the collimator section 3c through the optical fiber 5a; The reference light _r2 , which has been made into a parallel light by the above, is combined and guided onto a common optical path r. Note that the light source 5
contains a halogen lamp and a filter that converts the white light emitted by the halogen lamp into a distinguishable monochromatic light.

When laser processing is performed using an apparatus having such a configuration, first, the objective lens 1 of the microscope section 1 is
The workpiece 6 is placed near the eyepiece part 1g.
The machining location 6a of the workpiece 6 is magnified and observed through the lens, and then a spot of the reference light _r2 is formed on the machining location 6a, and the shape of the spot is observed through the microscope. By variously changing the shape of the opening 2c of the beam cross-section shaper 2, the spot shape of the reference beam is made into the shape to be processed. Thereafter, a laser beam _r1 is emitted from the laser device of the laser oscillator 4. As a result, the emitted laser beam _r1 is focused by the objective lens 1b onto the processing location 6a into a spot having approximately the same shape as the spot of the reference light, and desired processing is performed.

[Problem to be solved by the invention] By the way, in a laser processing apparatus such as the conventional example described above, if a commercially available almost standardized microscope can be used as the microscope section 1, this microscope section 1 can be newly designed. There is no need to create
The design and production of the entire device becomes extremely easy, and costs can be significantly reduced.

However _, in general commercially available microscopes, as shown by the dotted line _R3 in FIG. The lens barrel 1a is configured to focus from the upper end of the lens barrel 1a to a point P ₂ located downward in the figure, and when observed with the eyepiece 1g, the object located at this position P ₁ is in focus. It's becoming like that. Therefore, if such a commercially available microscope is used as it is as the microscope section 1 shown in FIG. 4, the opening 2c of the beam section shaper 2
The light r ₄ (indicated by the solid line in the figure) that has passed through is
The light is focused by the objective lens 1b, but the focusing point is located at a point _P3 different from the point _P1 .

That is, the position P ₁ that is in focus when observing with the eyepiece 1g and the point P ₃ on which the reference light r ₂ or laser light r ₁ is focused are shifted from each other. As a result, a problem arises in that accurate laser processing becomes difficult. An object of the present invention is to provide a laser processing device that eliminates the above-mentioned drawbacks.

[Means for Solving the Problems] In short, the laser processing device according to the present invention has a structure in which there is a
The light that has passed through the aperture of the beam cross-section shaper is once focused near a focal point of the objective lens located on the opposite side of the workpiece, and finally reaches the processing location of the workpiece through the objective lens. A focusing lens system is provided, so that even when the commercially available microscope is used, the reference beam and laser beam are focused on the processed area that is in focus when observed with the microscope. Specifically, a reference beam and a processing laser beam that share a common optical path are guided into the optical path of an objective lens system of a microscope that magnifies and observes the processing area of the workpiece. The spot shape of the reference light at the processing location is observed using the microscope before processing with the laser light, and the spot shape is set in the common optical path of the reference light and the laser light. By using a beam cross-section shaper that shapes the cross-sectional shape of these lights into the shape of the aperture using a light shielding means having an aperture, the spot shape of the reference light is made into the shape to be processed. In the laser processing apparatus, the shape to be processed by the laser beam at the processing location is the shape to be processed, wherein an opening of the beam section shaper is located between the objective lens system of the microscope and the beam section shaper. The light that has passed through is once focused in the vicinity of a focal point of the objective lens system located on the opposite side of the workpiece, and is finally focused on the processing location of the workpiece through the objective lens. It has a configuration characterized by providing a lens system.

[Function] In the above configuration, between the objective lens of the microscope and the beam cross-section shaper, the light that has passed through the opening of the beam cross-section shaper is directed to the opposite side of the objective lens from the workpiece. By providing a focusing lens system that once focuses near a focal point and finally focuses it on the processing location of the workpiece through the objective lens, it is possible to use a commercially available microscope as described above as the microscope. Even when used, the reference light and the laser light will be focused on the processing location that will be in focus when observed with the microscope.

[Example] FIG. 1 shows an example of a laser processing apparatus according to this invention.

This laser processing apparatus uses the above-mentioned commercially available microscope as the microscope section 1 in the conventional apparatus shown in FIG. 7. The configuration other than the condenser lens system 7 is the same as that shown in FIG. 4, so the same parts as in FIG. 4 are given the same reference numerals and redundant explanation will be omitted.

Now, in this embodiment, the condenser lens system 7
is composed of a cylindrical main body 7a and two plano-convex lenses 7b and 7c supported within the cylindrical main body 7a.

FIG. 2 is a partially enlarged sectional view showing the vicinity of the condensing lens system 7, in which the two plano-convex lenses 7b and 7c have a common optical axis and their flat parts face each other. As shown, the support member 7
d and 7e. in this case,
The focal lengths of these plano-convex lenses 7b and 7d are both 15 mm, and the distance L ₁ between their respective principal points O _b and O _c is 6 mm. The distance L ₂ between the principal point O _b of the plano-convex lens 7 b and the light shielding plate 2 b of the beam section shaper 2, and the principal point O _c of the plano-convex lens 7 c and the light convergence point P ₂ of the microscope section 1.
The distance L 3 and the distance L ₃ are both 30 mm. Note that in the above configuration, other lens systems including the objective lens 1b and the half mirror 1
Main optical systems such as e and 3b are coated with anti-chromatic aberration coating to prevent errors due to chromatic aberration.

According to the above configuration, the beam section shaper 2
The light r ₄ that has passed through the aperture 2c is once focused on the point P ₂ and then finally focused on the point P ₁ , that is, the processing location 6a of the workpiece 6, through the objective lens 1b. be done. As a result, the reference light and the laser beam are focused on the processing area 6a that is in focus when observed with the eyepiece 1g, and therefore the spot shape of the reference light is adjusted to the desired processing shape. By irradiating the spot with a laser beam, it is possible to accurately perform desired laser processing in a spot shape that is approximately the same as the spot shape of the reference beam.

According to this embodiment, the microscope section 1 includes:
Since a commercially available almost standardized microscope is used, there is no need to newly design and manufacture the microscope section 1, which makes the design and manufacture of the entire device extremely easy, and has the advantage of significantly reducing costs. has.

In the above embodiment, an example was shown in which a so-called infinite tube type microscope was used as the microscope section 1, but as shown in FIG. 3, a commercially available so-called finite tube type microscope may also be used. Of course.
In this case, the other configurations are exactly the same as in the previous embodiment, and even with this configuration, the same advantages as in the previous embodiment are obtained.

[Effects of the invention] As described in detail above, the present invention provides a system between the objective lens system of the microscope and the beam section shaper, in which the light that has passed through the aperture of the beam section shaper is transferred to the beam section of the objective lens. This system is equipped with a focusing lens system that once focuses near a focal point located on the opposite side of the workpiece, and finally focuses it on the processing location of the workpiece through the objective lens system. Even when a commercially available microscope is used, the reference beam and laser beam are focused on the processing location that is in focus when observed with the microscope, making accurate laser processing possible. This has the effect of making it easier to design and manufacture a laser processing device, as well as significantly reducing costs.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the laser processing apparatus according to the invention, FIG. 2 is a partially enlarged sectional view showing the vicinity of the condenser lens system 7 in FIG. 1, and FIG. The figure shows another embodiment of the present invention;
FIG. 4 is a diagram showing a conventional example. 1... Microscope section, 1b... Objective lens, 2...
Beam cross section shaper, 3... Optical coupler for guiding the reference light and laser light to a common optical path, 4... Laser oscillation unit that emits processing laser light, 5... Light source that generates reference light, 6... Workpiece, 6a... Processing location, 7... Focusing lens system.

Claims (1)

[Scope of Claim for Utility Model Registration] A reference beam and a processing laser beam having a common optical path are guided into the optical path of an objective lens system of a microscope for magnifying and observing a processing location of a workpiece, and the processing location is guided to the processing location. Before performing processing using the laser beam, the spot shape of the reference beam at the processing location is observed using the microscope, and an aperture is provided in the common optical path of the reference beam and the laser beam. The spot shape of the reference beam is shaped into the shape to be machined by a beam cross-section shaper that shapes the cross-sectional shape of these lights into the shape of the aperture using the light shielding means, which has a light shielding means. In the laser processing apparatus, the shape to be machined by the laser beam is set to the shape to be machined, and the light passing through the opening of the beam cross-section shaper is placed between the objective lens system of the microscope and the beam cross-section shaper. , a focusing lens system is provided, which is configured to once focus near a focal point of the objective lens system located on the opposite side of the workpiece, and finally focus it on a processing location of the workpiece through the objective lens system. A laser processing device characterized by: