Semiconductor chip assembly with copper/aluminum post/base heat spreader

Abstract

A semiconductor chip assembly includes a semiconductor device, a heat spreader, a conductive trace and an adhesive. The semiconductor device is electrically connected to the conductive trace and thermally connected to the heat spreader. The heat spreader includes a post and a base that include a copper surface layer and an aluminum core. The post extends upwardly from the base into an opening in the adhesive, and the base extends laterally from the post. The adhesive extends between the post and the conductive trace and between the base and the conductive trace. The conductive trace provides signal routing between a pad and a terminal.

1 . A semiconductor chip assembly, comprising:
 a semiconductor device;   an adhesive that includes an opening;   a heat spreader that includes a post and a base, wherein the post is adjacent to the base and extends above the base in an upward direction, the base extends below the post in a downward direction opposite the upward direction and extends laterally from the post in lateral directions orthogonal to the upward and downward directions, the post and the base include a copper surface layer and an aluminum core, the copper surface layer conformally coats and extends above the aluminum core, and the aluminum core of the post extends above the copper surface layer of the base; and   a conductive trace that includes a pad and a terminal;   wherein the semiconductor device is above and overlaps the post, is electrically connected to the pad and thereby electrically connected to the terminal, and is thermally connected to the post and thereby thermally connected to the base;   wherein the adhesive is mounted on and extends above the base, extends into a gap between the post and the pad, extends laterally from the post to or beyond the terminal and is sandwiched between the base and the pad;   wherein the pad is mounted on the adhesive and extends above the base; and   wherein the post extends into the opening, and the base extends below the semiconductor device, the adhesive and the pad.   
   
   
       2 . The assembly of  claim 1 , wherein the semiconductor device is an LED package that includes an LED chip. 
   
   
       3 . The assembly of  claim 2 , wherein the LED package is electrically connected to the pad using a first solder joint and is thermally connected to the heat spreader using a second solder joint. 
   
   
       4 . The assembly of  claim 1 , wherein the semiconductor device is a semiconductor chip. 
   
   
       5 . The assembly of  claim 4 , wherein the chip is electrically connected to the pad using a wire bond and is thermally connected to the heat spreader using a die attach. 
   
   
       6 . The assembly of  claim 1 , wherein the adhesive contacts the post in the gap and contacts the base, the pad and the terminal outside the gap. 
   
   
       7 . The assembly of  claim 1 , wherein the adhesive covers and surrounds the post in the lateral directions. 
   
   
       8 . The assembly of  claim 1 , wherein the adhesive conformally coats sidewalls of the post and a top surface of the base outside the post. 
   
   
       9 . The assembly of  claim 1 , wherein the adhesive fills the space between the base and the conductive trace. 
   
   
       10 . The assembly of  claim 1 , wherein the adhesive extends laterally from the post beyond and is overlapped by the terminal. 
   
   
       11 . The assembly of  claim 1 , wherein the adhesive extends to peripheral edges of the assembly. 
   
   
       12 . The assembly of  claim 1 , wherein the post is integral with the base. 
   
   
       13 . The assembly of  claim 1 , wherein the post is coplanar with the adhesive above a bottom surface of the pad. 
   
   
       14 . The assembly of  claim 1 , wherein the post has a cut-off conical shape in which its diameter decreases as it extends upwardly from the base to its flat top. 
   
   
       15 . The assembly of  claim 1 , wherein the base covers the semiconductor device, the post, the adhesive and the conductive trace in the downward direction and extends to peripheral edges of the assembly. 
   
   
       16 . The assembly of  claim 1 , wherein the post and the base include a nickel buffer layer that contacts and is sandwiched between and separates the copper surface layer and the aluminum core. 
   
   
       17 . The assembly of  claim 1 , wherein the heat spreader includes a cap that is above and adjacent to and covers in the upward direction and extends laterally in the lateral directions from the copper surface layer at a top of the post. 
   
   
       18 . The assembly of  claim 17 , wherein the cap is coplanar with the pad and the terminal above the adhesive. 
   
   
       19 . The assembly of  claim 17 , wherein the cap has a rectangular or square shape and the top of the post has a circular shape. 
   
   
       20 . The assembly of  claim 17 , wherein the cap is sized and shaped to accommodate a thermal contact surface of the semiconductor device, and the top of the post is not sized and shaped to accommodate the thermal contact surface of the semiconductor device. 
   
   
       21 . A semiconductor chip assembly, comprising:
 a semiconductor device;   an adhesive that includes an opening;   a heat spreader that includes a post and a base, wherein the post is adjacent to the base and extends above the base in an upward direction, the base extends below the post in a downward direction opposite the upward direction and extends laterally from the post in lateral directions orthogonal to the upward and downward directions, the post and the base include a copper surface layer, a nickel buffer layer and an aluminum core, the copper surface layer conformally coats and extends above the aluminum core and covers the aluminum core in the upward direction, the aluminum core extends below the copper surface layer and covers the copper surface layer in the downward direction, the aluminum core of the post extends above the copper surface layer of the base, the copper surface layer of the post covers and surrounds the aluminum core of the post in the lateral directions, and the nickel buffer layer contacts and is sandwiched between and separates the copper surface layer and the aluminum core; and   a conductive trace that includes a pad, a terminal and a routing line, wherein an electrically conductive path between the pad and the terminal includes the routing line;   wherein the semiconductor device is mounted on the heat spreader, overlaps the post, is electrically connected to the pad and thereby electrically connected to the terminal, and is thermally connected to the post and thereby thermally connected to the base;   wherein the adhesive is mounted on and extends above the base, extends into a gap between the post and the pad, is sandwiched between the base and the conductive trace outside the gap, surrounds the post in the lateral directions and extends to peripheral edges of the assembly;   wherein the conductive trace is mounted on the adhesive and extends above the base, and the pad, the terminal and the routing line contact and overlap the adhesive; and   wherein the post extends into the opening, and the base extends below the semiconductor device, the adhesive and the conductive trace, covers the post, the adhesive and the conductive trace in the downward direction and extends to peripheral edges of the assembly.   
   
   
       22 . The assembly of  claim 21 , wherein the semiconductor device is an LED package that includes an LED chip, is mounted on the pad using a first solder joint and on the heat spreader using a second solder joint, is electrically connected to the pad using the first solder joint and is thermally connected to the heat spreader using the second solder joint. 
   
   
       23 . The assembly of  claim 21 , wherein the adhesive contacts the post in the gap, contacts the base, the pad, the terminal and the routing line outside the gap, contacts the copper surface layer and is spaced from the aluminum core, covers and surrounds the post in the lateral directions, covers the conductive trace in the downward direction, covers the base outside the post in the upward direction and fills the space between the base and the conductive trace. 
   
   
       24 . The assembly of  claim 21 , wherein the post is coplanar with the adhesive above a bottom of the conductive trace and the pad is coplanar with the terminal above the adhesive. 
   
   
       25 . The assembly of  claim 21 , wherein the aluminum core of the base has a thickness that is greater than a thickness of the copper surface layer, and the aluminum core of the post has a height above the aluminum core of the base that is greater than five times the thickness of the copper surface layer. 
   
   
       26 . A semiconductor chip assembly, comprising:
 a semiconductor device;   an adhesive that includes an opening;   a heat spreader that includes a post and a base, wherein the post is adjacent to the base and extends above the base in an upward direction, the base extends below the post in a downward direction opposite the upward direction and extends laterally from the post in lateral directions orthogonal to the upward and downward directions, the post and the base include a copper surface layer and an aluminum core, the copper surface layer conformally coats and extends above the aluminum core, and the aluminum core of the post extends above the copper surface layer of the base;   a substrate that includes a pad and a dielectric layer, wherein an aperture extends through the substrate; and   a terminal;   wherein the semiconductor device is above and overlaps the post, is electrically connected to the pad and thereby electrically connected to the terminal, and is thermally connected to the post and thereby thermally connected to the base;   wherein the adhesive is mounted on and extends above the base, extends into a gap in the aperture between the post and the substrate, extends across the dielectric layer in the gap, extends laterally from the post to or beyond the terminal and is sandwiched between the post and the dielectric layer and between the base and the substrate;   wherein the substrate is mounted on the adhesive and extends above the base; and   wherein the post extends into the opening and the aperture, and the base extends below the semiconductor device, the adhesive and the substrate.   
   
   
       27 . The assembly of  claim 26 , wherein the semiconductor device is an LED package that includes an LED chip, the substrate includes the terminal, the terminal extends above the dielectric layer and the adhesive extends laterally from the post beyond and is overlapped by the terminal. 
   
   
       28 . The assembly of  claim 27 , wherein the LED package is electrically connected to the pad using a first solder joint and is thermally connected to the heat spreader using a second solder joint. 
   
   
       29 . The assembly of  claim 26 , wherein the semiconductor device is a semiconductor chip, the substrate excludes the terminal, the terminal extends below the adhesive and the adhesive extends laterally from the post beyond and overlaps the terminal. 
   
   
       30 . The assembly of  claim 29 , wherein the chip is electrically connected to the pad using a wire bond and is thermally connected to the heat spreader using a die attach. 
   
   
       31 . The assembly of  claim 26 , wherein the adhesive contacts the post and the dielectric layer in the gap and contacts the base and the dielectric layer outside the gap. 
   
   
       32 . The assembly of  claim 26 , wherein the adhesive covers and surrounds the post in the lateral directions. 
   
   
       33 . The assembly of  claim 26 , wherein the adhesive fills the space between the post and the dielectric layer and between the base and the substrate. 
   
   
       34 . The assembly of  claim 26 , wherein the adhesive is contained in the space between the heat spreader and the substrate. 
   
   
       35 . The assembly of  claim 26 , wherein the adhesive extends to peripheral edges of the assembly. 
   
   
       36 . The assembly of  claim 26 , wherein the substrate is spaced from the post and the base and is a laminated structure. 
   
   
       37 . The assembly of  claim 26 , wherein the post is integral with the base. 
   
   
       38 . The assembly of  claim 26 , wherein the post is coplanar with the adhesive above the dielectric layer. 
   
   
       39 . The assembly of  claim 26 , wherein the post has a cut-off conical shape in which its diameter decreases as it extends upwardly from the base to its flat top. 
   
   
       40 . The assembly of  claim 26 , wherein the base covers the semiconductor device, the post, the adhesive and the substrate in the downward direction and extends to peripheral edges of the assembly. 
   
   
       41 . The assembly of  claim 26 , wherein the post and the base include a nickel buffer layer that is sandwiched between and separates the copper surface layer and the aluminum core. 
   
   
       42 . The assembly of  claim 26 , wherein the heat spreader includes a cap that is above and adjacent to and covers in the upward direction and extends laterally in the lateral directions from the copper surface layer at a top of the post. 
   
   
       43 . The assembly of  claim 42 , wherein the cap is coplanar with the pad above the dielectric layer. 
   
   
       44 . The assembly of  claim 42 , wherein the cap has a rectangular or square shape and the top of the post has a circular shape. 
   
   
       45 . The assembly of  claim 42 , wherein the cap is sized and shaped to accommodate a thermal contact surface of the semiconductor device, and the top of the post is not sized and shaped to accommodate the thermal contact surface of the semiconductor device. 
   
   
       46 . A semiconductor chip assembly, comprising:
 a semiconductor device;   an adhesive that includes an opening;   a heat spreader that includes a post and a base, wherein the post is adjacent to the base and extends above the base in an upward direction, the base extends below the post in a downward direction opposite the upward direction and extends laterally from the post in lateral directions orthogonal to the upward and downward directions, the post and the base include a copper surface layer, a nickel buffer layer and an aluminum core, the copper surface layer conformally coats and extends above the aluminum core and covers the aluminum core in the upward direction, the aluminum core extends below the copper surface layer and covers the copper surface layer in the downward direction, the aluminum core of the post extends above the copper surface layer of the base, the copper surface layer of the post covers and surrounds the aluminum core of the post in the lateral directions copper surface layer, and the nickel buffer layer contacts and is sandwiched between and separates the copper surface layer and the aluminum core; and   a substrate that includes a pad, a terminal, a routing line and a dielectric layer, wherein the pad, the terminal and the routing line contact and extend above the dielectric layer, an electrically conductive path between the pad and the terminal includes the routing line, and an aperture extends through the substrate;   wherein the semiconductor device is mounted on the heat spreader, overlaps the post, is electrically connected to the pad and thereby electrically connected to the terminal, and is thermally connected to the post and thereby thermally connected to the base;   wherein the adhesive is mounted on and extends above the base, extends into a gap in the aperture between the post and the substrate, extends across the dielectric layer in the gap, is sandwiched between the post and the dielectric layer in the gap, is sandwiched between the base and the substrate outside the gap, surrounds the post in the lateral directions, is overlapped by the pad, the terminal and the routing line and extends to peripheral edges of the assembly;   wherein the substrate is mounted on the adhesive and extends above the base; and   wherein the post extends into the opening and the aperture and above the dielectric layer, and the base extends below the semiconductor device, the adhesive and the substrate, covers the post, the adhesive and the substrate in the downward direction and extends to peripheral edges of the assembly.   
   
   
       47 . The assembly of  claim 46 , wherein the semiconductor device is an LED package that includes an LED chip, is mounted on the pad using a first solder joint and on the heat spreader using a second solder joint, is electrically connected to the pad using the first solder joint and is thermally connected to the heat spreader using the second solder joint. 
   
   
       48 . The assembly of  claim 46 , wherein the substrate is spaced from the post and the base, and the adhesive contacts the post and the dielectric layer in the gap, contacts the base and the dielectric layer outside the gap, contacts the copper surface layer, is spaced from the aluminum core and fills the gap. 
   
   
       49 . The assembly of  claim 46 , wherein the post is coplanar with the adhesive above the dielectric layer and the pad is coplanar with the terminal above the dielectric layer. 
   
   
       50 . The assembly of  claim 46 , wherein the aluminum core of the base has a thickness that is greater than a thickness of the copper surface layer, and the aluminum core of the post has a height above the aluminum core of the base that is greater than five times the thickness of the copper surface layer.