JPS63303746A - Optical marking device - Google Patents

Abstract

PURPOSE:To reduce risks to an operator caused by scattering of laser beam significantly and prevent a mask from being thermally deformed by inserting it in an optical resonator. CONSTITUTION:A laser device 1 is composed of two optical resonators 1a, 1b and a laser medium 1c, and a mask 2 with a marking pattern formed previously is inserted between a total reflector 1a and the laser medium 1c. Consequently, when laser beam is oscillated, it has a beam cross-section gain distribution corresponding to the mask pattern. Therefore, the cross-section intensity distribution of a laser flux 6 emitted from an output mirror 1b revisualizes a mask pattern. In this way, not only the pattern portion of the mask is not subjected to strong laser beam projection, but also no laser beams are scattered by the pattern occurs. An optical system for image projection 3 is capable of any one of functions such as reduction, no magnification and enlargement of light flux cross-section profile.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an optical marking device.

[Conventional technology]

Optical marking devices are used to mark significant symbols such as letters, numbers, and symbols.
This is used to apply a predetermined pattern (hereinafter referred to as a predetermined pattern) to a target article.By irradiating a powerful laser beam, the surface layer of the target article or the target article itself (in the case of a defect) is burnt out, thereby creating a predetermined pattern. Stamp the pattern onto the target item. In this case, there are two methods: a drawing method in which the object is moved so as to draw a predetermined pattern while irradiating the laser beam, and a projection method in which the laser beam having a beam cross section of a predetermined pattern is simply irradiated.

Target articles include, for example, completed semiconductor chips, semiconductor chips in the process of being manufactured, resist films formed on semiconductor substrates, and other small articles such as dental implants. Optical marking devices are particularly useful when marking minute predetermined patterns.

To explain the structure of a projection type optical marking device, conventionally, this type of device (for example, a CO8 laser marker) irradiates a mask (2) with laser light from a laser device (1), as shown in Fig. 3. Then, the mask pattern of the mask (2) created by this transmitted light is projected (imaged) and printed onto a target article, such as an IC chip (4), using a projection optical system (3).

The projection optical system (3) enlarges, reduces, or otherwise modifies the same cross-sectional shape as the mask pattern to produce a light beam having a cross-sectional shape of a predetermined pattern, and also bends the light beam to bring it to a desired irradiation position. It's a thing, but it's not required.

[The problem that the invention attempts to solve]

Therefore, the part of the laser beam that does not pass through the mask (2) is absorbed by the mask (2) itself or scattered around the mask (2), causing damage to the mask (2) due to temperature rise and safety for workers. The disadvantage was that it had an unfavorable effect on the surface.

It is an object of the present invention to solve these drawbacks and provide a marking device having a configuration in which unnecessary absorption or scattering of laser light does not occur on the mask.

[Means for solving problems]

The technical point of the present invention is to oscillate a laser beam having the same or modified shape as the mask pattern by inserting a mask into the optical resonator of a laser device that is a marking light source.

[Example 1] (]) FIG. 1 shows the basic configuration of an embodiment of the present invention.

This device is roughly divided into (1) laser device, mask (2),
(3) Consists of an image projection optical system.

(2) Although the laser device in this embodiment is assumed to be a C08 laser and a YAG laser, other types of lasers such as an excimer laser may also be used.

(3) The laser device (1) consists of two optical resonators (1
a), (1b) and the laser medium (1
c).

(4) In this embodiment, a mask (2) is inserted between the total reflection mirror (la) of the optical resonators (1a) and (1b) and the laser medium (1c). A marking pattern is previously formed on the mask (2).

(5) Therefore, when the laser beam oscillates, it has a beam cross-sectional gain distribution that corresponds to the mask pattern, so the cross-sectional intensity distribution of the laser beam (6) emitted from the output a (1b) corresponds to the mask pattern. Will be reproducing it.

(6) With this configuration, the patterned portion of the mask is not irradiated with strong laser light, and the laser light is not scattered by the pattern, making it possible to perform stable and safe marking exposure over a long period of time.

(7) The image forming projection optical system (3) in FIG. 1 may be used to reduce, equal magnify, or enlarge the cross-sectional shape of the light beam, and may be omitted depending on the case.

[Example 2] A second example is shown in FIG. 2. In this example, a beam expander (7) is inserted between the laser medium (IC) and the mask (2) in the first example. , the expanded laser beam passes through a mask (2) and is reflected by a total reflection mirror (1a). This has the advantage that a reduction image projection optical system can be omitted when marking is performed by reducing the mask pattern.

(Effects of the Invention) As described above, according to the present invention, by inserting a mask into a laser device, a laser beam having a beam cross-sectional shape corresponding to the mask pattern is emitted. absorb and suffer thermal deformation or damage,
■The drawback of increased danger to surrounding workers due to scattering of laser light by the mask is significantly reduced. Furthermore, since the second embodiment shown in FIG. 2 does not require an image projection optical system, the laser energy per shot can be increased without worrying about damage to the optical system due to laser light, and the throughput ( It also has the advantage of improving productivity.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram illustrating the configuration of a first embodiment of the apparatus according to the present invention. FIG. 2 is a conceptual diagram illustrating the configuration of the same Example 2. FIG. 3 is a conceptual diagram illustrating the configuration of a conventional marking device. (Explanation of symbols of main parts) lc... Laser medium 2... Mask 3... Imaging projection optical system 4... Target article to be marked 5...・・・
・Transportation platform 6 for symmetrical items... Laser light

Claims (1)

[Claims] An optical marking device comprising a laser device and a mask and outputting a laser beam having a cross-sectional shape that is the same as or modified from a mask pattern, characterized in that the mask is disposed within an optical resonator of the laser device. optical marking device.