Indium Corporation

Fen Chen

Ning-Cheng Lee

Hongwen Zhang

Francis M Mutuku

Jie Geng

Fengying Zhou

Hongtao Xia

Some implementations of the disclosure are directed to a method, comprising: receiving a sheet of graphite comprising a first surface and a second surface opposite the first surface; and perforating the sheet in a first plurality of locations from the first surface through the second surface to form a first plurality of perforations through the sheet and a first plurality of protrusions of the graphite oriented outward from the second surface, the first plurality of protrusions configured to conduct heat away from a plane of the sheet. Further implementations comprise perforating the sheet in a second plurality of locations from the second surface through the first surface to form a second plurality of perforations through the sheet and a second plurality of protrusions of graphite material oriented outward from the first surface, wherein the second plurality of protrusions are configured to conduct heat away from the plane of the sheet.

Method for preparing graphite sheets with piercing treatment to enhance thermal conduction

Implementations of the disclosure are directed to a lead-free mixed solder powder paste suitable for low temperature to middle temperature soldering applications. The lead-free solder paste may consist of: an amount of a first solder alloy powder between 44 wt % and 83 wt %, the first solder alloy powder comprising Sn; an amount of a second solder alloy powder between 5 wt % to 44 wt %, the second alloy powder comprising Sn, where the first solder alloy powder has a liquidus temperature lower than a solidus temperature of the second solder alloy powder; and a remainder of flux. The solder paste may be used for reflow at a peak temperature below the solidus temperature of the higher solidus temperature solder powder but above the melting temperature of the lower solidus temperature one.

Low temperature melting and mid temperature melting lead-free solder paste with mixed solder alloy powders

The disclosure describes techniques for eliminating or reducing non-wet open (NWO) defect formation by using a low activity flux to prevent a solder paste from sticking to ball grid array (BGA) solder balls during reflow soldering. The low activity flux may be configured such that: i) it creates a barrier that prevents the solder paste from sticking to the solder balls of the BGA; and ii) it does not impede the formation of solder joints during reflow. In implementations, a solid coating of the low activity flux may be formed over balls of the BGA, and the BGA may then be bonded to a PCB during reflow. In implementations, the balls of a BGA may be dipped in a low-activity creamy or liquid flux prior to reflow. In some implementations, the flux may applied on a solder paste printed on pads of the PCB, followed by placement of a BGA.

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Suzhou, China

Fen Chen