Method for manufacturing a GaN based LED of a back hole structure

A method for manufacturing a gallium nitride based lighting emitting diode of a back hole structure comprising steps of:

• Step 1:
• epitaxially growing an N type gallium nitride (GaN) layer, a multi-quantum wells emitting active region and a P type gallium nitride layer in turn on an insulation substrate made of sapphire or other materials by a metal organic chemical vapor deposition (MOCVD) method;
• Step 2:
• etching a designed chip pattern into the N type GaN layer by photoetching, and forming a P type ohmic contact electrode and an N type ohmic contact electrode on the P type GaN layer and N type GaN layer, respectively;
• Step 3:
• thinning the sapphire substrate from its back side by a milling method or an ion thinning technique;
• Step 4:
• scribing the chip to divide the dies on the epitaxial chip into individual die;
• Step 5:
• forming a SiO2 insulation isolation layer on both sides of the silicon chip by a thermal oxidation method, forming a metal electrode on a face side by evaporation or sputtering, and forming a back hole pattern on a back side by photoetching, then corroding the SiO2;
• Step 6:
• etching or corroding the silicon chip on the back side by ICP dry etching or KOH as anisotropic corrosion solution of silicon, until the SiO2 insulation isolation layer on the face side being exposed;
• continuing the corrosion by HF as corrosion solution of silicon oxide, until the metal electrode being exposed, thus forming a back hole;
• Step 7:
• plating copper with high heat conductivity in the back hole until the surface thereof and the surface of the back side of the silicon chip are in a plane;
• Step 8:
• forming an electrode connected to the N electrode of the die by photoetching on the face side of the silicon chip;
• Step 9:
• forming a bump pattern for plating on the face side of the silicon chip by thick resist photoetching, selectively plating metal bumps respectively connected to the P type ohmic contact electrode and the N type ohmic contact electrode of the die;
• Step 10:
• forming a layer of alloy with low melting point on the back side of the silicon chip, thus forming a base;
• Step 11:
• directly attaching the base to a heat sink of a housing by heating the alloy on the back side of the base;
• Step 12:
• bonding the die with the face side of the base through the metal bumps by a flip-chip bonder, leading an N electrode of the LED from the metal electrode formed on the face surface of the silicon chip, and leading a P electrode of the LED from the back side of the heat sink of the housing.