Tool Tips—August 2018

I want to make an opening in the solder mask right above a trace that is acting like a guard ring. Do I really need to go and buy the Allegro Productivity Toolbox add-on for using the Cross-Copy tool for a basic operation like that??

/F

A land grid array (LGA) package including a substrate having a plurality of lands formed on a first surface of the substrate, a semiconductor chip mounted on a second surface of the substrate, a connection portion connecting the semiconductor chip and the substrate, and a support layer formed on part of a surface of a first land.

A method for producing a solder joint between at least one base part (2) and at least one first component (3) includes the following steps: providing the base part (2); partially blasting a surface of the base part (2) using a SACO blasting agent, the blasting material (50) of which has a silicate coating (52), in such a way that a SACO-blasted region (20) and a non-blasted positioning region (40) are present; and soldering the at least first component (3) onto the non-blasted positioning region (40), wherein the SACO-blasted region (20) acts as a solder resist.

A solder joint manufactured of an alloy essentially composed of 0.01-7.6 wt % Cu, 0.001-6 wt % Ni, and the remaining of Sn. Each of Cu and Ni has a maximum concentration range. The lower limit of the range of Ni is 0.01 wt % and preferably 0.03 wt %. The upper limit of the range of Ni is 0.3 wt % and preferably 0.1 wt %. The lower limit of the range of Cu is 0.1 wt % and preferably 0.2 wt %. The upper limit of the range of Cu is 7 wt % and preferably 0.92 wt %. The invention includes the solder joint essentially having these compositions.

In a reflow process, a plurality of solder bumps between a first workpiece and a second workpiece is melted. During a solidification stage of the plurality of solder bumps, the plurality of solder bumps is cooled at a first cooling rate. After the solidification stage is finished, the plurality of solder bumps is cooled at a second cooling rate lower than the first cooling rate.

A solder bump structure for a ball grid array (BGA) includes at least one under bump metal (UBM) layer and a solder bump formed over the at least one UBM layer. The solder bump has a bump width and a bump height and the ratio of the bump height over the bump width is less than 1.

A method of retaining a solder mass within a solder-bearing component is provided and includes the steps of: (a) forming a plurality of fingers in the solder-bearing component at one edge thereof, with each finger being defined by a pair of slots formed in the solder-bearing component; and (b) interleaving a solder mass between the fingers such that the solder mass is securely held by the fingers. The solder-bearing component includes any number of different types of components where a solder mass is held thereby, e.g., leads, terminals, connectors, electromagnetic shields, etc.

Transient liquid phase sintering compositions comprising one or more high melting point metals and one or more low melting temperature alloys are known in the art as useful compositions for creating electrically and/or thermally conductive pathways in electronic applications. The present invention provides transient liquid phase sintering compositions that employ non-eutectic low melting temperature alloys for improved sintering and metal matrix properties.

A solder paste comprises an amount of a first solder alloy powder between about 60 wt % to about 92 wt %; an amount of a second solder alloy powder greater than 0 wt % and less than about 12 wt %; and a flux; wherein the first solder alloy powder comprises a first solder alloy that has a solidus temperature above about 260° C.; and wherein the second solder alloy powder comprises a second solder alloy that has a solidus temperature that is less than about 250° C.

Provided herein is a resin fluxed solder paste that exhibits a desirable solder bump reinforcement effect without requiring an underfill process. The disclosure also provides a mount structure. The resin fluxed solder paste includes a non-resinic powder containing a solder powder and an inorganic powder; and a flux containing a first epoxy resin, a curing agent, and an organic acid. The non-resinic powder accounts for 30 to 90 wt % of the total, and the surface of the inorganic powder is covered with an organic resin.

If you design wire bond packages, you’re familiar with the need for the bond fingers and rings on the package substrate layers to be exposed through the solder mask layer. If they aren’t, it becomes… rather difficult… to bon...(read more)

Hi All,

I've just about to finish my first PCB layout, and I want to understand some 2 issues better:

1. Soldermask layer: when exactly do we want to define for some SMT pad (say at Pad Designer tool), to have soldermask top and when we want to define solermask bottom? 

if it's a TH pad, I guess we always want to define both layers soldermask (top, bottom), because the pads are crossing all the layers. However, if it's a SMT pad, which SM we want?

2. Pastemask layer: is this layer necessary for the gerber files generation, when we have SMT components in our circuit?

And again, when we define for a TH/SMT pads pastemask top, and when Pastemask bottom?

Thanks!

Presentation by David Vaughan of Taiyo America

Presentation by Jasbir Bath of Christopher Associates.