US 11,810,821 B2
Semiconductor chip and method for manufacturing the same
Masatake Nagaya, Kariya (JP); Kazukuni Hara, Kariya (JP); Daisuke Kawaguchi, Hamamatsu (JP); Toshiki Yui, Hamamatsu (JP); Chiaki Sasaoka, Nagoya (JP); Jun Kojima, Nagoya (JP); and Shoichi Onda, Nagoya (JP)
Assigned to DENSO CORPORATION, Kariya (JP); HAMAMATSU PHOTONICS K.K., Hamamatsu (JP); and National University Corporation Tokai National Higher Education and Research System, Nagoya (JP)
Filed by DENSO CORPORATION, Kariya (JP); HAMAMATSU PHOTONICS K.K., Hamamatsu (JP); and National University Corporation Tokai National Higher Education and Research System, Nagoya (JP)
Filed on Apr. 13, 2021, as Appl. No. 17/229,137.
Claims priority of application No. 2020-073157 (JP), filed on Apr. 15, 2020.
Prior Publication US 2021/0327757 A1, Oct. 21, 2021
Int. Cl. H01L 21/78 (2006.01); H01L 29/20 (2006.01); H01L 21/268 (2006.01); H01L 21/02 (2006.01); H01L 29/06 (2006.01)
CPC H01L 21/78 (2013.01) [H01L 21/0254 (2013.01); H01L 21/02389 (2013.01); H01L 21/268 (2013.01); H01L 29/0657 (2013.01); H01L 29/2003 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A method for manufacturing a semiconductor chip on which a semiconductor element is formed, the method comprising:
preparing a gallium nitride wafer which is made of gallium nitride and has a first surface and a second surface;
forming an epitaxial film on the first surface of the gallium nitride wafer to define a surface of the epitaxial film as a third surface of a processed wafer having a plurality of chip formation regions on the third surface, and to define a surface of a gallium nitride wafer side of the processed wafer as a fourth surface of the processed wafer;
forming an element component of the semiconductor element on the third surface in each of the plurality of chip formation regions;
arranging a holding member, via a gate electrode, on the third surface of the processed wafer;
forming a division structure for dividing the chip formation regions;
after forming the division structure, irradiating an inside of the processed wafer with a laser beam from the fourth surface of the processed wafer, and forming a wafer transformation layer by separating a nitrogen atom from a gallium atom and discharging the nitrogen atom from the division structure along a surface direction of the processed wafer;
after the irradiating of the inside of the processed wafer, dividing the processed wafer at the wafer transformation layer as a boundary to divide the processed wafer into a chip formation wafer on the third surface of the processed wafer and a recycle wafer on the fourth surface of the processed wafer;
forming an element component of the semiconductor element on a fifth surface of the chip formation wafer from which the recycle wafer is divided; and
after the forming of the element component on the fifth surface, retrieving the semiconductor chip from the chip formation wafer, wherein:
the forming of the division structure includes:
irradiating the laser beam from the fourth surface of the processed wafer to form a chip transformation layer in an outer periphery of each chip formation region by separating the nitrogen atom from the gallium atom; and
before retrieving the semiconductor chip, expanding the holding member along the surface direction of the chip formation wafer to divide the chip formation regions at the chip transformation layer as a boundary, and
the division structure is formed from an inside of the gallium nitride wafer to penetrate the epitaxial film and reach the third surface of the processed wafer.