JPS6380221A - Light irradiating device - Google Patents

Abstract

PURPOSE:To obtain a square beam whose energy density is constant and which has an exact shape, and to improve the productivity by placing the first and the second triangular prisms in an optical system, and dividing an incident light being elliptical or circular, into four. CONSTITUTION:A beam 1b of an elliptical shape is split in the short axis direction by the first triangular prism 16, these split half elliptical beams 1d, 1e are moved each other along the long axis direction and superposed, and thereafter, these superposed half elliptical beams 1d, 1e are further split in the long axis direction by the second triangular prism 17. In such a way, by moving and superposing beams 1f, 1g and 1h, 1i which are split to 1/4 and superposed in the long axis direction, in the short axis direction, a beam 1j of a rectangular shape can be formed. A linear part of the elliptical beam 1b which is generated by the split goes to a rectangular external form line, therefore, a sharp rectangular beam 1j having high accuracy can be formed.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a light irradiation device for obtaining split light.

[Summary of the invention]

The present invention is a light irradiation device for obtaining divided light, and by dividing the light into four using an optical system having two triangular prisms, square light can be obtained. It is something.

[Conventional technology]

For example, when soldering a flat package IC (FPIC) or the like, a laser beam is used as energy to melt the solder. Conventionally, as a method of irradiating this laser beam, for example, as shown in FIG. 13, a circular laser beam (1) emitted from a laser oscillator is
How to move the C-chip along the part to be soldered, as shown in Figure 14, transform the circular laser beam (1) into a rectangular (rectangular) beam (3) using the mask plate (2). There is a method to irradiate it.

[Problem that the invention seeks to solve]

According to the above-mentioned method of moving and irradiating with a circular beam, (1) processing time is long and productivity is low;
) requires a mechanism to move while irradiating; (iii
) There are many parameters for setting conditions (output, moving speed, etc.), (iv) When irradiating two locations at the same time, two optical cores are required to separate the light using the output source. (V) Based on the above, There are disadvantages such as high cost and high costs. Also, according to the method of transforming into a rectangular beam using a mask plate,
(1) Large energy loss (tn mask plate is heated and needs to be cooled) (iii)
It has problems such as the size of the mask plate is required, which is disadvantageous in terms of sweep, and (1) the energy density is not constant.

The present invention provides a light irradiation device that can solve the above problems.

[Means for solving problems]

In the light irradiation device αυ according to the present invention, the first and second triangular prisms αe and aη are arranged in the optical system to divide the elliptical or circular incident light (1) into four parts. Convert into a beam of shape (lj).

[Effect]

According to the present invention, first, the first triangular prism (161) is used to create an elliptical (rectangular beam (1j)), and to create a square beam (1j), it is used to create a circular beam (1j).
1) The beam (lb) of 1) is divided in the minor axis direction, and this divided half becomes an elliptical beam (ld).

(le) along the long axis direction! After moving the elliptical beams (ld) and (le) to the second triangular prism (Iη), the two halves of the elliptical beams (ld) and (le) are further divided in the major axis direction by a second triangular prism (Iη). In this way, it is divided into 1/4 and superimposed in the long axis direction to form nine beams (If), (Ig), (lh), (li
) by moving along the short axis direction and overlapping them, it becomes possible to produce a rectangular beam (1j). That is, the elliptical (or circular) beam (1b) is 90 degrees from the center.
The divided beam (If) is divided into four by a straight line every 0.

By moving (Ig), (lh), and (li) toward the center and overlapping each other, the straight line part of the elliptical beam (1b) created by the division becomes a rectangular rectangular outline, which improves accuracy. It is possible to produce a sharp rectangular beam (1j).

〔Example〕

The present invention will be described in detail with reference to the drawings.

FIG. 1 shows a perspective view of a light irradiation device αV according to the first embodiment. In this light irradiation device αυ, a collimator lens C13 is arranged below the optical core 9α2 guided from a laser oscillator (not shown), and below this, in order, a cylindrical concave lens α, a cylindrical convex lens a, and a first triangular lens are arranged. It is constructed by arranging in a straight line a prism (Le) and a second triangular prism whose edges are arranged in a direction perpendicular to the edges of the first triangular prism (Ie).

Next, the operation of the light irradiation device αυ will be explained with reference to FIGS. 2 to 6. FIG. 2 is a side view of the optical system constituting the apparatus αυ, and FIGS. 3A to 3C are side views of the beam (1) showing the energy density at positions corresponding to the side view of FIG. FIG. 4 is a plan view of the beam (1) at a position corresponding to the side view of FIG. 2; 5 is a front view of the optical system, and FIGS. 6A and 6C are front views of the beam (1) showing the energy density at corresponding positions in the front view of FIG. First, the laser beam (1) emitted from the optical fiber (I21) spreads radially as shown in Fig. 4 AK, and has a steep Gaussian energy distribution as shown in Fig. 3 A and Fig. 6 A. By passing this beam (1) through the collimator lens CI3, it becomes a parallel beam (1) with a circular cross section as shown in FIG.
1a). Next, this parallel beam (la) is made incident on the cylindrical concave lens α4, and as shown in FIG. 4C, the width is expanded in only one direction to form an elliptical beam (1b). By forming the elliptical beam (1b) in this way, this radially expanded elliptical beam (1b) of 11 degrees exhibiting a gentle Gaussian energy distribution as shown in Figures 3B and 6B can be created. , to form a parallel elliptical beam (1c) by making it incident on a cylindrical convex lens O9 arranged on the axis of the elliptical beam (lb). Next, this parallel elliptical beam (1c) is made incident on the first triangular prism haze, and the elliptical beam (lc) is divided into two along the minor axis direction, resulting in a half elliptical beam (1d). , (le) is refracted to the angle to be synthesized. The fourth diagram shows a state in which the halves of the elliptical beams (ld) and (le) thus divided into two are in the process of overlapping each other along the major axis direction. Then, this beam that has been divided into two and is in the process of being combined (
ld), (le) are incident on the second triangular prism αη, and half of the ellipse (ld), (le) is synthesized.
By further dividing the beam into two along the major axis direction, contrary to the first prism (151), a total of four divided beams (i
f), (Ig), (lh), (li), and this second prism (lk) forms the beam (if), (Ig), (lh), (li) with the short axis In other words, as shown in FIG. 4EK, the elliptical beam (1b
) is divided into four, and the four divided beams (lf),
(Ig).

(lh) and (1i) are each moved toward the center until the dividing line forms a rectangular outline. At the laser processing surface αa, a rectangular laser beam (1j) is obtained as shown in FIG. 4PK.

FIG. 3 CIC shows the energy density distribution from the side of this rectangular laser beam (lj), and FIG. 3 CIC shows the energy density distribution from the front. FIG. 7 shows a three-dimensional diagram of this energy density distribution.

As described above, the rectangular laser beam (lj) obtained according to the present invention has a flat upper surface of the energy density distribution, so that the energy density is equal at all positions in the rectangular region. It's showing. Note that the aspect ratio of the rectangular beam (lj) can be changed using a cylindrical lens α4. (It is especially possible to change the curvature of 151.

Next, with reference to FIGS. 8 and 9, an embodiment will be shown in which the present invention is applied to a flat package IC (FPIC) (2υ soldered ffK. A parallel laser beam (1
a) with a cylindrical concave 1 (14) and an elliptical beam (
lb) K deformation, then a parallel elliptical beam (IC) with a cylindrical convex lens aS, and then split into a transmitted beam (lk) and a reflected beam (11) K using a half mirror, and then a reflected beam (lffi). is a total reflection mirror CI! 3
refract 9d3 by. and both beams (lk)
, (lffi) are the first triangular prism aS and the second triangular prism (17a), (17
b), the rectangular beam (lj) is simultaneously irradiated onto the terminals to be soldered on both sides of the flat package IC (211).

The rectangular beam (lj) in the above embodiment has a uniform energy density in any part of the rectangular irradiation surface. On the other hand, as shown in Fig. 10, the elliptical beam (1b) is divided along the short axis to form half beams (ld), (16), which are refracted in the long axis direction and overlapped. From K, a rectangular beam (lj) is obtained which has a Gaussian energy density distribution in the short axis direction, but with equal energy density along the long axis. Depending on the type of laser processing (e.g. annealing),
A rectangular beam having such an energy density distribution can also be used, and FIGS. 11 and 12 show the configuration of a light irradiation device (111) for this purpose. In this device (111, a collimator (not shown) is ), a cylindrical concave lens I, a cylindrical convex lens 19, and a triangular prism α9 are arranged in order at a predetermined interval.First, a circular laser beam (1a) made parallel by a collimator is made incident on the cylindrical concave lens α4 to form an elliptical beam ( lb)
K transforms. K as shown in Figure 3 CIC.

The laser beam (1
Although the energy density in a) has a steep Gaussian distribution, the beam (lb) after passing has a gentle shape as shown in FIG. 12BK. Next, this radially spread elliptical beam (1b) is made into a parallel elliptical beam (IC) by passing through a cylindrical convex lens (151), and then transmitted through a triangular prism (le). An elliptical beam (IC) is divided into two beams (ld), (
le) After K division, combine to create rectangular H-A(lj). Looking at this situation in terms of energy density, as shown in Figure 12C, the elliptical laser beam (1b) is incident on the triangular prism (IIK) and the beam (1b) is split symmetrically, as shown in Figure 12 after passing through the cylinder. Both beams (l
d) Move so that , (le) overlap each other,
As shown in FIG. 12EK, a rectangular laser beam (lj) in which both beams (ld) and (le) overlap is obtained on the processing surface αε.

〔Effect of the invention〕

According to the invention, a square beam with a constant energy density and a precise shape is obtained from a circular or elliptical beam. Furthermore, when applied to a laser processing device for semiconductor devices, for example, since it is thermally stable and has good energy efficiency, processing time can be shortened and productivity can be increased. Furthermore, the mechanism of the irradiation device can be simplified, and the cost of the optical system can be reduced. In addition, improved space efficiency is enabled compared to devices that use conventional mask plates to obtain square beams.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of the embodiment, Fig. 2 is a side view of the optical system, Fig. 3 is a side view of the beam showing energy density, Fig. 4 is a plan view of the beam, and Fig. 5 is a front view of the optical system. Figure 6 is a front view of the beam, Figure 7 is a perspective view of a rectangular beam, Figure 8 is a side view of another embodiment, Figure 9 is a front view of another embodiment,
FIG. 10 is a perspective view of a rectangular beam, FIG. 11 is a front view of another optical system, and FIG. 12 is a front view of a beam of another optical system.
FIG. 13 is a plan view of a conventional example, and FIG. 14 is a perspective view of another conventional example. (1), (la) to (lffi) are laser beams, u is the light irradiation position, (131 is a remeter lens, 0 is a cylindrical concave lens, a9 is a cylindrical convex lens, αG is the first triangular prism, (171, (17a)
, (17b) is the second triangular prism. Implementation Idari 0,68L → S L Figure 1 Photoelectric clothing n Reimu phantom C ri Upper 21 arrows I#JffilS ri. , -44 and surface. (English, ' + Le - Steal U list) ゛Figure 2 Figure 3 Figure 4 Rectangle and... - Melon # - Hole figure Figure 1 Figure 10 and others I11 Implementation row - Fabric surface m Front view of the I row of the I row, the first prize, Fig. 9. ! Figure 13

Claims (1)

[Claims] A light irradiation device characterized in that an optical system having two triangular prisms is arranged to obtain four-split light.