The Particle And Defect Control For 300mm Furnace Process

The oxidation, diffusion, deposition, annealing and alloys in the integrated are all involved furnace process. The particle and defect in the furnace process can cause yield loss and scrap products with potential risks, the worst case may even cause the machine to stop line and add additional maintenance cost. Base on the furnace process technology, we give the solutions for the particle and defect problems. We focus on three problems are boat and dummy distortion particle in high-temp oxidation tool, Si3N4 tool condense defect and LPCVD bump defect.In this paper,we use America KLA-Tencor company’ Surf-scan SP2 inspection system to monitor particle in high temperature oxidation tool, found that after oxidation process often have nearly a hundred more than lum particles on 300mm wafers. This type particle is caused by boat and dummy distortion. We add rotation 45 degree step in dummy re-cycle flow and modify boat un-load temperature from 750 to 700 degree in the recipe to improve boat and dummy distortion probability. These new methods make the number of particles on 300mm wafer under the single-digit levels. We also design a measurement tool to measure boat distortion accurately.In this paper another study is a defect case in Si3N4 tool. There are hundreds of crystallized defect and size is less than 0.2um on 300mm wafers with KLA machine analyze. For this type defect, we shorten the NH3 pure time to 5mins, modify the boat unload temperature from 400 to 650 degree in the recipe, finally we modify cooling water start condition to keep manifold temperature stable. These methods make the number of defects by the hundreds of to almost nothing.Finally, the paper studier the LPCVD bump defect, the defect count is more than three hundreds with KLA machine analyze. After FIB, we found the defect is abnormal growth in the poly silicon deposition process. We add cycle-purge between process to clean furnace ambience, shorten PM thickness to 3um; we shorten dummy use count to one from five, optimize dummy recycle flow and add clean wafer back step to reduce defect happening ratio. These methods make the number of particles under the single-digit levels.Using many analysis methods and combining the quality control techniques to find out the root cause of the defect coming source, establishing the defect occurred mode. Discovering the most optimized defect solution plan by designed many experiment, solving furnace process defect problem is our final purpose. We hope the solved defect problem can decrease the production cost, enhance the production efficiency and yield.