Electric heating – Metal heating – By arc
Patent
1995-08-28
1998-10-13
Evans, Geoffrey S.
Electric heating
Metal heating
By arc
21912168, 21912173, B23K 2600
Patent
active
058214976
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a laser marking system and a method of laser marking, and, in particular, to a laser marking system and a laser marking method suitable for marking identification numbers, letters, and the like on workpieces in semiconductor fabrication processes.
2. Description of the Related Art
Generally, when product numbers, other identification numbers, and letters are marked on workpieces by a laser marking apparatus, each of the workpieces is placed just below a laser emitting opening. After the workpiece has been marked, it is unloaded. For the apparatuses of this type, various technologies that identify workpiece types and align marking positions have been proposed so as to improve marking contents and alignment. In addition, to effectively mark workpieces, a high speed marking technology that quickly changes marking objects has been proposed (as Japanese Patent Laid-Open Publication No. 2-187288).
Although these technologies improve marking appearance, speed, and alignment accuracy, technologies that allow total operating efficiency with respect to workpiece conveying apparatus, operating type, or operation time to be improved as marking systems have not been yet disclosed. Thus, with these conventional technologies, a large number of workpieces cannot be effectively conveyed and quickly marked.
Generally, workpieces are marked by an ink jet system. In the ink jet system, a relative position between a workpiece and an ink jet nozzle is changed by a conveying apparatus. Thus, an interlocking operation between the conveying apparatus and the ink jet system is required (as disclosed in Japanese Patent Laid-Open Publication No. 57-14981).
Recently, as the size of workpieces such as semiconductor devices is decreasing, small marking numbers and letters and high marking accuracy are being required. Thus, laser marking systems are now being studied, instead of the ink jet systems. In a conventional laser marking apparatus, laser light generated by a laser oscillator is raster scanned by a deflector onto a mask surface. The workpiece surface is marked with the laser light that is transmitted by the mask. In reality, an entire mark to be marked is divided into several mark blocks. These mark blocks are sequentially displayed on a liquid crystal mask. By raster scanning laser light onto the liquid crystal mask, the transmitted light is radiated to the workpiece surface by the deflector. By repeating this operation sequence, the entire pattern is marked. This method is disclosed in Japanese Patent Laid-Open Publication No. 2-187287.
However, this laser marking apparatus requires that the deflectors raster scan the laser beam in the X and Y directions onto a pattern displayed on a mask. When the laser light that has been transmitted by the mask is deflected in the X and Y directions along the workpiece conveying line, another deflector, that deflects the divided pattern blocks along the workpiece plane, is required so as to combine these pattern blocks. Thus, the X and Y deflecting and scanning drive systems are required both in the laser beam incident optical path and in the mask transmitting optical path. Thus, in this related art reference, the scale of the apparatus is large, and the number of items to be controlled is large.
In addition, according to the laser marking apparatus having a liquid crystal mask, different patterns are displayed on the mask, one after the other. The positional accuracy of the marking depends on the dot pitch. In other words, a mark displayed on the mask depends on whether each dot thereof transmits the laser beam. Thus, a positional accuracy higher than the dot pitch cannot be obtained. Since a gap between dots is not marked, the resultant mark becomes unclear.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a laser marking system and a method of laser marking for maximizing the efficiency of the entire operating timing of the marking operation against the workpiece loading/un
REFERENCES:
patent: 4638144 (1987-01-01), Latta, Jr.
patent: 4818835 (1989-04-01), Kuwabara et al.
patent: 5132510 (1992-07-01), Klingel et al.
patent: 5192848 (1993-03-01), Miyakawa et al.
patent: 5260542 (1993-11-01), Ishiguro et al.
patent: 5260728 (1993-11-01), Yoshioka et al.
patent: 5309273 (1994-05-01), Mori et al.
patent: 5608563 (1997-03-01), Matsumara et al.
Matsumura Yukinori
Mori Akira
Tsuda Yukihiro
Yamazaki Taku
Evans Geoffrey S.
Kabushiki Kaisha Seisakusho
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