Abstract: A semiconductor wafer into which devices such as an integrated circuit is to be formed is gettered by regions in the wafer activated by a laser beam. The laser beam is directed onto the surface of the wafer opposite to that where the devices are to be formed. The power input to the laser is controlled such that the surface temperature of the region of the semiconductor wafer where the laser beam is applied first reaches the melting point of the material, such as silicon, and the melting commences. Then the temperature in the melt rises above the melting temperature, but stays below the boiling temperature of the material of the wafer. A superheated melt is formed. The result is that the solid-liquid interface moves deep into the material. The position of the melt is directly under the laser beam. The solidified material is positioned behind the beam as the beam scans the wafer. A depression is formed under the beam while the material rises behind the laser beam.

Abstract: Methods of making semiconductor devices using the technique of impact sound stressing are disclosed. Impact sound stressing (ISS) is a mechanical acoustical technique to damage, in a known and controlled manner, semiconductor wafers. Wafers are subjected to ISS on the backsides before semiconductor processing steps. The application of ISS before the first high temperature application will control the generation and subsequent direction of flow (gradient) of vacancies (interstitials) generated through all device high temperature processing steps including ion implantation. ISS redirects the flow of vacancies/interstitials into the backside away from the device area of the wafer. Thus, the device area is swept clean in a gettering action of vacancy/interstitials and their complexes which are detrimental to device performance. The technique of impact sound stressing finds application in improving the performance of all semiconductor devices, specifically dynamic memories, bipolars, solar cells and power devices.