Method of forming a thin wafer stack for a wafer level package
AssigneeSamsung Electronics Co., Ltd.
InventorsHyeon Hwang, Ki-Kwon Jeong
Life of this patent
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Abstract
A method of forming a stack of thin wafers provides a wafer level stack to greatly reduce process time compared to a method where individually separated chips are stacked after a wafer is sawed. A rigid planar wafer support member stabilizes and planarizes each wafer while it is thin or its thickness is reduced and during subsequent wafer processing. Thinned wafers are stacked and the external support members are removed by applying heat or ultraviolet (UV) light to an expandable adhesive layer between the support members and the thin wafers. The stacked wafers then can be further processed and packaged without thin-wafer warping, cracking or breaking. A wafer level package made in accordance with the invented method also is disclosed.
Claims23
A method of forming a stack of wafers, comprising:
- providing a first wafer to produce a first bump that extends at least partway through the first wafer and protrudes from a front surface thereof;
- affixing a support member to the front surface of the first wafer after providing the first wafer;
- reducing a thickness of the first wafer to form a first thinned wafer, wherein a lower end of the first bump protrudes from a rear surface of the first thinned wafer;
- providing a second wafer to produce a second bump that protrudes from a front surface thereof;
- joining the first thinned wafer and the second wafer so that the protruded lower end of the first bump is electrically connected to the protruding second bump;
- and
- completely removing the support member from the first thinned wafer.
A method of forming a stack of wafers, the method comprising:
- providing a first wafer to produce a first bump that extends at least partway therethrough and protrudes from a back surface thereof;
- providing a second wafer to produce a second bump that extends at least partway therethrough and protrudes from a front surface thereof;
- affixing a first support member to the front surface of the second wafer after providing the second wafer;
- reducing the second wafer in thickness to form a second thinned wafer so that a lower end of the second bump protrudes also from a rear surface of the second thinned wafer;
- attaching a second support member to the rear surface of the second thinned wafer;
- completely removing the first support member from the second thinned wafer to expose an upper protruded end of the second bump;
- joining the first wafer and the second thinned wafer so that the first bump is electrically connected to the upper end of the second bump;
- and
- completely removing the second support member from the second thinned wafer to expose the lower end of the second bump.
A method of forming a stack of wafers, the method comprising:
- providing a first wafer to produce a first bump that extends at least partway through the first wafer and protrudes from a front surface thereof;
- affixing a first support member to the front surface of the first wafer after providing the first wafer;
- reducing the first wafer in thickness to form a first thinned wafer so that a lower end of the first bump protrudes from a rear surface of the first thinned wafer;
- providing a second wafer to produce a second bump that extends at least partway through the second wafer and protrudes from a front surface thereof;
- affixing a second support member to the front surface of the second wafer after providing the second wafer;
- reducing the second wafer in thickness to form a second thinned wafer so that a lower end of the second bump protrudes from a rear surface of the second thinned wafer;
- attaching a third support member to the rear surface of the second thinned wafer;
- completely removing the second support member from the second thinned wafer to expose an upper end of the second bump;
- joining the first thinned wafer and the second thinned wafer so that the first bump is electrically connected to the upper end of the second bump;
- and
- completely removing the first support member from the first thinned wafer to expose an upper end of the first bump and completely removing the third support member from the second thinned wafer to expose the lower end of the second bump.
A method of forming a stack of wafers, the method comprising:
- preparing a first wafer to produce a first bump extending at least partway through the first wafer and protruding from a rear surface thereof;
- after preparing the first wafer, affixing a first support member to a front surface of the first wafer;
- preparing a second wafer to produce a second bump extending at least partway through the second wafer and protruding from a front surface thereof;
- after preparing the second wafer, affixing a second support member to a rear surface of the second wafer;
- joining the first wafer and the second wafer so that a lower end of the first bump is electrically connected to an upper end of the second bump;
- and
- completely removing the first and second support members from the first and second wafers.
Dependencies are inferred from the claim text.