| 摘要 |
A wafer structure with conductive bumps and fabrication method thereof are disclosed herein. Conductive bumps are later converted into conductive balls. A central area and a marginal area are defined on the wafer. To achieve heights among conductive balls formed on the wafer structure, the sizes (can be but not limited to one) of under bump metallurgy (UBM) layer blocks in the central area are smaller than that in the marginal area. The fabrication procedure for forming under bump metallurgy layer blocks of different size includes depositing a photoresist layer on the metallurgy layer and pattern the photoresist with a photomask of smaller opening area for the central area than for the marginal area, and removing the photoresist layer and the portion of metallurgy layer under the photoresist layer.
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