Semiconductor package and method of fabricating the same
A semiconductor package includes a first semiconductor chip mounted on a substrate, a first conductive post disposed on the substrate and spaced apart from the first semiconductor chip, a second semiconductor chip disposed on the first semiconductor chip and the first conductive post, and a mold layer on the substrate that covers the first and second semiconductor chips and the first conductive post. The second semiconductor chip is supported on the first semiconductor chip by a first dummy solder terminal provided between the first and second semiconductor chips, and is coupled to the first conductive post by a first signal solder terminal provided between the first conductive post and the second semiconductor chip. The first dummy solder terminal is in direct contact with a top surface of the first semiconductor chip, and is electrically disconnected from the second semiconductor chip.
1 . A method of fabricating a semiconductor package, comprising:
providing a substrate;
forming a conductive post on the substrate;
mounting a first semiconductor chip on the substrate spaced apart from the conductive post;
mounting a second semiconductor chip on the conductive post and the first semiconductor chip; and
forming a mold layer on the substrate to cover the conductive post, the first semiconductor chip, and the second semiconductor chip,
wherein the mounting the second semiconductor chip comprises
attaching a first solder terminal to a dummy pad of the second semiconductor chip and a second solder terminal to a signal pad of the second semiconductor chip,
aligning the second semiconductor chip on the first semiconductor chip to place the second solder terminal attached to the signal pad on the conductive post and to place the first solder terminal attached to the dummy pad on the first semiconductor chip, and
performing a reflow process on the first and second solder terminals to form a signal solder terminal connecting the signal pad to the conductive post and a dummy solder terminal connecting the dummy pad to a top surface of the first semiconductor chip,
wherein a bottom surface of the second semiconductor chip is substantially parallel to a top surface of the substrate after the reflow process,
wherein the top surface of the first semiconductor chip and a top surface of the conductive post are located at different levels from the substrate, and
wherein a height difference between the top surface of the first semiconductor chip and the top surface of the conductive post from the substrate is smaller than a first height of the dummy solder terminal and a second height of the signal solder terminal.
2 . The method of claim 1 , wherein the height difference between the top surface of the first semiconductor chip and the top surface of the conductive post from the substrate is 0.1 times to 0.5 times the first height of the dummy solder terminal and the second height of the signal solder terminal.
3 . The method of claim 1 , wherein the dummy pad is electrically disconnected from an integrated circuit of the second semiconductor chip, and
the signal pad is electrically connected to the integrated circuit of the second semiconductor chip.
4 . The method of claim 1 , wherein the second semiconductor chip is inclined at an angle with respect to the top surface of the substrate after the aligning the second semiconductor chip on the first semiconductor chip, and
the first and second solder terminals are melted during the reflow process to level the second semiconductor chip to be substantially parallel to the top surface of the substrate.
5 . The method of claim 1 , wherein the forming the conductive post comprises:
forming a sacrificial layer on the substrate;
forming a penetration hole to penetrate the sacrificial layer and expose the substrate;
filling the penetration hole with a conductive material; and
removing the sacrificial layer.
6 . The method of claim 1 , wherein the dummy solder terminal is in direct contact with the top surface of the first semiconductor chip, and is electrically disconnected from the second semiconductor chip.
7 . The method of claim 1 wherein the first semiconductor chip has a first active surface facing the substrate,
the second semiconductor chip has a second active surface facing the substrate, and
the second semiconductor chip and the first semiconductor chip are shifted from each other, and a part of the second active surface of the second semiconductor chip is not overlapped with the first semiconductor chip.
8 . The method of claim 1 wherein the mold layer fills a space between the substrate and the second semiconductor chip, and surrounds the conductive post between the substrate and the second semiconductor chip.
9 . A method of fabricating a semiconductor package, comprising:
providing a substrate;
forming a conductive post on the substrate;
mounting a first semiconductor chip on the substrate spaced apart from the conductive post, a top surface of the first semiconductor chip and a top surface of the conductive post are located at different levels from the substrate;
attaching solder terminals to a bottom surface of a second semiconductor chip, the solder terminals have a same volume;
aligning the second semiconductor chip on the first semiconductor chip to place the solder terminals on the conductive post and on the first semiconductor chip, the second semiconductor chip is inclined with respect to the first semiconductor chip;
performing a reflow process on the solder terminals to form a signal solder terminal connecting to the conductive post and a dummy solder terminal connecting to the top surface of the first semiconductor chip, a first height of the dummy solder terminal and a second height of the signal solder terminal are different from each other after the reflow process; and
forming a mold layer on the substrate to cover the conductive post, the first semiconductor chip, and the second semiconductor chip.
10 . The method of claim 9 , wherein a bottom surface of the second semiconductor chip is substantially parallel to a top surface of the substrate after the reflow process.
11 . The method of claim 9 , wherein the solder terminals include a first solder terminal to a dummy pad of the second semiconductor chip and a second solder terminal to a signal pad of the second semiconductor chip, and
wherein after aligning the second semiconductor chip on the first semiconductor chip, the second solder terminal is placed on the conductive post and the first solder terminal is placed on the first semiconductor chip.
12 . The method of claim 11 , wherein a height difference between the top surface of the first semiconductor chip and the top surface of the conductive post from the substrate is smaller than the first height of the dummy solder terminal and the second height of the signal solder terminal.
13 . The method of claim 12 , wherein the height difference between the top surface of the first semiconductor chip and the top surface of the conductive post from the substrate is 0.1 times to 0.5 times the first height of the dummy solder terminal and the second height of the signal solder terminal.
14 . The method of claim 11 , wherein the dummy pad is electrically disconnected from an integrated circuit of the second semiconductor chip, and
the signal pad is electrically connected to the integrated circuit of the second semiconductor chip.
15 . The method of claim 9 , wherein the second semiconductor chip is inclined at an angle with respect to the top surface of the substrate after the aligning the second semiconductor chip on the first semiconductor chip, and
the solder terminals are melted during the reflow process to level the second semiconductor chip to be substantially parallel to the top surface of the substrate.
16 . The method of claim 9 , wherein the forming the conductive post comprises:
forming a sacrificial layer on the substrate;
forming a penetration hole to penetrate the sacrificial layer and expose the substrate;
filling the penetration hole with a conductive material; and
removing the sacrificial layer.
17 . The method of claim 9 , wherein the dummy solder terminal is in direct contact with the top surface of the first semiconductor chip, and is electrically disconnected from the second semiconductor chip.
18 . A method of fabricating a semiconductor package, comprising:
providing a substrate;
forming a conductive post on the substrate;
mounting a first semiconductor chip on the substrate spaced apart from the conductive post;
mounting a second semiconductor chip on the conductive post and the first semiconductor chip; and
forming a mold layer on the substrate to cover the conductive post, the first semiconductor chip, and the second semiconductor chip,
wherein the mounting the second semiconductor chip comprises
attaching a first solder terminal to a dummy pad of the second semiconductor chip and a second solder terminal to a signal pad of the second semiconductor chip,
aligning the second semiconductor chip on the first semiconductor chip to place the second solder terminal attached to the signal pad on the conductive post and to place the first solder terminal attached to the dummy pad on the first semiconductor chip, and
performing a reflow process on the first and second solder terminals to form a signal solder terminal connecting the signal pad to the conductive post and a dummy solder terminal connecting the dummy pad to a top surface of the first semiconductor chip,
wherein a bottom surface of the second semiconductor chip is substantially parallel to a top surface of the substrate after the reflow process,
wherein the first and second solder terminals have a same volume, and
wherein a first height of the dummy solder terminal and a second height of the signal solder terminal are different from each other after the reflow process.