Stretchable electronic system based on controlled buckled flexible printed circuit board (pcb)

Patent metadata

Field	Value
Publication number	US-2018192520-A1
Application number	US-201615394501-A
Country	US
Kind code	A1
Filing date	Dec 29, 2016
Priority date	Dec 29, 2016
Publication date	Jul 5, 2018
Grant date	—

Abstract

A microelectronic device system and a method of forming a microelectronic device are described. The microelectronic device includes a flex printed circuit board (PCB) having two or more electrical sub-systems that are electrically coupled by a plurality of conductive traces, where the flex PCB may be a buckled flex PCB. The microelectronic device includes a plurality of anchoring sites formed on a backside surface of the flex PCB. The microelectronic device encapsulates an elastomer over the flex PCB, the electrical sub-systems, and the conductive traces. The microelectronic device may stretch in a unidirectional and bidirectional axis. The microelectronic device may have electronic components attached to the electrical sub-systems. The microelectronic device may have stretchable segments where each of the stretchable segments is formed between a pair of anchoring sites. The microelectronic device may have three-dimensional (3D) conductive traces, where the 3D conductive traces are 3D meandering traces.

First claim

1 . A microelectronic device, comprising:
a flex printed circuit board (PCB) having two or more electrical sub-systems that are electrically coupled by a plurality of conductive traces;
a plurality of anchoring sites formed on a backside surface of the flex PCB; and
an elastomer encapsulating the flex PCB, the two or more electrical sub-systems, and the plurality of conductive traces.

2 . The microelectronic device of claim 1 , wherein the flex PCB is a buckled flex PCB.

3 . The microelectronic device of claim 1 , wherein the flex PCB includes a plurality of stretchable segments.

4 . The microelectronic device of claim 3 , wherein each stretchable segment is formed between a pair of anchoring sites.

5 . The microelectronic device of claim 3 , wherein the electrical sub-systems are positioned above the rigid pads.

6 . The microelectronic device of claim 1 , wherein each of the electrical sub-systems includes a first plurality of conductive traces at one end and a second plurality of conductive traces at another end.

7 . The microelectronic device of claim 1 , wherein each of the electrical sub-systems includes at least one of a package substrate, a printed circuit board, and one or more electrical components.

8 . The microelectronic device of claim 7 , wherein the one or more electrical components includes a semiconductor die.

9 . The microelectronic device of claim 8 , wherein the semiconductor die is at least one of a flip-chip and a wire-bonded die.

10 . The microelectronic device of claim 1 , wherein the plurality of conductive traces include at least one of two-dimensional (2D) conductive traces and three-dimensional (3D) conductive traces, and wherein the plurality of conductive traces are formed with a plurality of shapes or a plurality of sizes.

11 . The microelectronic device of claim I 0 , wherein the 3D conductive traces are 3D meandering traces.

12 . The microelectronic device of claim 1 , further comprising a hard overmold layer formed over each of the electrical sub-systems.

13 . The microelectronic device of claim 1 , wherein the flex PCB is stretched in at least one of a unidirectional axis and a bidirectional axis, and wherein the buckled flex PCB includes one or more fully anchored segments and one or more partially anchored segments.

14 . A microelectronic device, comprising:
a first flex PCB having a first plurality of electrical sub-systems that are electrically coupled by a first plurality of conductive traces; a second flex PCB having a second plurality of electrical sub-systems that are electrically coupled by a second plurality of conductive traces, wherein the first flex PCB is connected to the second flex PCB with the first and second plurality of conductive traces; a plurality of anchoring sites formed on a backside surface of the first and second flex PCBs; and an elastomer encapsulating the first and second plurality of electrical sub-systems, the first and second plurality of conductive traces, and the first and second flex PCBs that are connected to each other.

15 . The microelectronic device of claim 14 , wherein the first and second flex PCBs are connected to form a 3D stacked flex PCB, wherein the 3D stacked flex PCB includes a plurality of stretchable segments, and wherein each stretchable segment is formed between a pair of anchoring sites.

16 . The microelectronic device of claim 14 , further comprising:
a plurality of rigid pads formed on the backside surface of the flex PCB, wherein the first
and second plurality of electrical sub-systems are positioned above the plurality of rigid pads; and
a hard overmold layer formed over each of the electrical sub-systems.

17 . A method of forming a microelectronic device, comprising:
attaching a flex printed circuit board (PCB) over a rigid support, wherein the flex PCB includes two or more electrical sub-systems that are electrically coupled by a plurality of conductive traces; depositing an adhesive layer over a backside surface of the flex PCB to form a plurality of anchoring sites;
bonding a frontside surface of an elastomer to the backside surface of the flex PCB;
releasing, at a pre-strain position, the elastomer to form one or more stretchable segments on
the flex PCB; and
forming an encapsulation layer over the flex PCB, the elastomer, the two or more electrical sub-systems, and the plurality of conductive traces.

18 . The method of claim 17 , further comprising assembling one or more electronic components on each of the electrical sub-systems of the flex PCB.

19 . The method of claim 17 , further comprising stretching the elastomer to the pre-strain position and activating the frontside surface of the pre-strained elastomer, prior to bonding the frontside surface of the elastomer to the backside surface of the flex PCB.

20 . The method of claim 17 , wherein the flex PCB is a buckled flex PCB.

21 . The method of claim 17 , wherein each stretchable segment is formed between a pair of anchoring sites.

22 . The method of claim 17 , further comprising forming two or more rigid pads over the backside surface of the flex PCB with the deposited adhesive layer.

23 . The method of claim 17 , wherein the plurality of conductive traces include at least one of two-dimensional (2D) conductive traces and three-dimensional (3D) conductive traces, and wherein the 3D conductive traces are 3D meandering traces.

24 . The method of claim 17 , wherein the plurality of conductive traces are formed with a plurality of shapes or a plurality of sizes.

25 . The method of claim 17 , wherein the flex PCB is stretched in at least one of a unidirectional axis and a bidirectional axis.

Assignees

• Intel Corp

Inventors

• Choong Chwee Lin
• Mar Kheng Tat

Classifications

• H10W90/401

  characterised by multiple insulating or insulated package substrates, interposers or RDLs · CPC title

• H10W70/65

  Shapes or dispositions of interconnections · CPC title

• H10W74/114

  by a substrate and the encapsulations · CPC title

• H10W74/01

  Manufacture or treatment · CPC title

• H10W70/688

  Flexible insulating substrates · CPC title