| United States Patent | 6,433,303 |
| Liu , et al. | August 13, 2002 |
A method and apparatus for forming an array of microcavities in the surface of a metal film uses an excimer laser or an ultrashort laser which to produce a beam of laser light pulses. An optical mask divides the beam into multiple beams and a lens system focuses the multiple beams onto the metal film. The device operates by generating multiple beams of laser pulses of a first diameter and then magnifying the pulses by a magnification factor less than 1 to produce multiple beams of pulses having a second diameter, less than the first diameter, which are applied to the metal film. The magnification factor and the intensity of the laser is such that the fluence of the laser on the optical mask is not sufficient to cause ablation while the fluence on the metal film is sufficient to cause ablation. A diffractive optical element may be used in the device in place of the optical mask. The apparatus includes a quarter wave plate that converts the beam of laser light pulses into a beam of circularly polarized pulses. The apparatus also includes a device that homogenizes the intensity of the laser light pulses before they are applied to the optical mask.
| Inventors: | Liu; Xinbing (Acton, MA); Takeda; Mamoru (Kyoto, JP); Ogawa; Hisahito (Nara, JP) |
| Assignee: | Matsushita Electric Industrial Co., Ltd. (Osaka, JP) |
| Appl. No.: | 541640 |
| Filed: | March 31, 2000 |
| 4322600 | Mar., 1982 | Crahay. | |
| 4734558 | Mar., 1988 | Nakano et al. | |
| 4937424 | Jun., 1990 | Yasui et al. | |
| 5168454 | Dec., 1992 | LaPlante et al. | |
| 5296673 | Mar., 1994 | Smith. | |
| 5367143 | Nov., 1994 | White, Jr. | |
| 5376771 | Dec., 1994 | Roy. | |
| 5414239 | May., 1995 | Terabayashi et al. | |
| 5596594 | Jan., 1997 | Egawa. | |
| 5676866 | Oct., 1997 | In den Baumen et al. | |
| 5792411 | Aug., 1998 | Morris et al. | |
| 5948289 | Sep., 1999 | Noda et al. | |
| 5955839 | Sep., 1999 | Jaffe et al. | |
| 6038075 | Mar., 2000 | Jamazaki et al. | |
| 6040552 | Mar., 2000 | Jain et al. | |
| 6058132 | May., 2000 | Iso et al. | |
| 6087625 | Jul., 2000 | Iso. | |
| 6120976 | Sep., 2000 | Treadwell et al. | |
| 6172329 | Jan., 2001 | Shoemaker et al. | |
| 6184490 | Feb., 2001 | Schweizer. | |
| 6208458 | Mar., 2001 | Galvanauskas et al. | |
| 6211485 | Apr., 2001 | Burgess. | |
| 6215099 | Apr., 2001 | Livshits. | |
| Foreign Patent Documents | |||
| 19744368 | May., 1999 | DE. | |