Mitigating semiconductor package warpage using improved stiffener ring
A semiconductor package includes a substrate, a die mounted on the substrate, and a stiffener ring mounted on the substrate and surrounding at least a portion of the die. The stiffener ring includes at least a first portion and a second portion circumferentially disposed along a perimeter of the stiffener ring. The first portion is characterized by a first effective stiffness, and the second portion is characterized by a second effective stiffness different from the first effective stiffness.
1 . A semiconductor package comprising:
a substrate;
a die mounted on the substrate; and
a stiffener ring mounted on the substrate and surrounding at least a portion of the die, the stiffener ring comprising at least a first portion and a second portion circumferentially disposed along a perimeter of the stiffener ring, wherein the first portion is characterized by a first effective stiffness, and the second portion is characterized by a second effective stiffness different from the first effective stiffness, wherein a difference between the first effective stiffness and the second effective stiffness is established by a varying thickness profile between the first portion and the second portion, and wherein the first portion is characterized by a first thickness, and the second portion is characterized by a second thickness different from the first thickness, and wherein a transition between the first thickness and the second thickness is a stepped transition or a tapered transition.
2 . The semiconductor package of claim 1 , wherein the stiffener ring is configured, by the first effective stiffness and the second effective stiffness, to reduce warpage of the semiconductor package across a temperature range.
3 . The semiconductor package of claim 2 , wherein the temperature range is between an ambient temperature and a reflow temperature.
4 . The semiconductor package of claim 1 , wherein the difference between the first effective stiffness and the second effective stiffness is further established by
a varying material composition between the first portion and the second portion.
5 . The semiconductor package of claim 4 , wherein the first portion comprises a first material, and the second portion comprises a second material different from the first material.
6 . The semiconductor package of claim 5 , wherein at least one of the first material or the second material comprises a non-metal material.
7 . The semiconductor package of claim 5 , wherein at least one of the first material or the second material comprises at least one of carbon fiber or carbon nanotubes.
8 . The semiconductor package of claim 5 , wherein the first portion comprises a first laminated structure including a first plurality of layers, and the second portion comprises a second laminated structure including a second plurality of layers.
9 . The semiconductor package of claim 8 , wherein the first laminated structure of the first portion and the second laminated structure of the second portion differ in at least one of (i) a number of layers, (ii) layer thicknesses, or (iii) layer material compositions.
10 . The semiconductor package of claim 1 , wherein the first portion comprises a first thickness profile that varies within the first portion.
11 . The semiconductor package of claim 10 , wherein the second portion comprises a second thickness profile that varies within the second portion, the second thickness profile being different from the first thickness profile.
12 . The semiconductor package of claim 1 , wherein the stiffener ring further comprises a third portion circumferentially disposed along the perimeter of the stiffener ring, wherein the third portion is characterized by a third effective stiffness different from the first effective stiffness and the second effective stiffness.
13 . The semiconductor package of claim 1 , wherein the first effective stiffness is selected based on a first warpage characteristic associated with a first region of the semiconductor package, and wherein the second effective stiffness is selected based on a second warpage characteristic associated with a second region of the semiconductor package different from the first region.
14 . A stiffener ring comprising:
a perimeter defining an opening;
a first portion circumferentially disposed along a first segment of the perimeter, wherein the first portion is characterized by a first effective stiffness; and
a second portion circumferentially disposed along a second segment of the perimeter, wherein the second portion is characterized by a second effective stiffness different from the first effective stiffness, wherein a difference between the first effective stiffness and the second effective stiffness is established by a varying thickness profile between the first portion and the second portion, and wherein the first portion is characterized by a first thickness, and the second portion is characterized by a second thickness different from the first thickness, and wherein a transition between the first thickness and the second thickness is a stepped transition or a tapered transition.
15 . The stiffener ring of claim 14 , wherein a difference between the first effective stiffness and the second effective stiffness is established by at least one of:
a varying thickness profile between the first portion and the second portion; or
a varying material composition between the first portion and the second portion.
16 . A method comprising:
mounting a die on a substrate; and
mounting a stiffener ring on the substrate such that the stiffener ring surrounds at least a portion of the die, the stiffener ring comprising at least a first portion and a second portion circumferentially disposed along a perimeter of the stiffener ring, wherein the first portion is characterized by a first effective stiffness, and the second portion is characterized by a second effective stiffness different from the first effective stiffness, wherein a difference between the first effective stiffness and the second effective stiffness is established by a varying thickness profile between the first portion and the second portion, and wherein the first portion is characterized by a first thickness, and the second portion is characterized by a second thickness different from the first thickness, and wherein a transition between the first thickness and the second thickness is a stepped transition or a tapered transition.
17 . The method of claim 16 , wherein a difference between the first effective stiffness and the second effective stiffness is established by at least one of:
a varying thickness profile between the first portion and the second portion; or
a varying material composition between the first portion and the second portion.