Abstract: Implementations of the disclosure are directed to a thermal via filling solder paste that exhibits little to no volume loss during reflow. The solder paste may include a solder powder such as tin-silver-copper alloy, a high melting temperature powder (e.g., a copper powder) having a higher melting temperature than the solder powder, and flux. The high melting temperature powder may be configured to have a melting temperature significantly higher than the solder powder. During reflow, the solder powder may melt and wet to the high melting temperature powder, forming intermetallic compounds that keep the via holes filled during and after reflow soldering.

Abstract: A SnAgCuSb-based Pb-free solder alloy is disclosed. The disclosed solder alloy is particularly suitable for, but not limited to, producing solder joints, in the form of solder preforms, solder balls, solder powder, or solder paste (a mixture of solder powder and flux), for harsh environment electronics.

Abstract: Some implementations of the disclosure are directed to low melting temperature (e.g., liquidus temperature below 210° C.) SnBi or Snln solder alloys. A SnBi solder alloy may consist of 2 to 60 wt % Bi; optionally, one or more of: up to 16 wt % In, up to 4.5 wt % Ag, up to 2 wt % Cu, up to 12 wt % Sb, up to 2.5 wt % Zn, up to 1.5 wt % Ni, up to 1.5 wt % Co, up to 1.5 wt % Ge, up to 1.5 wt % P, and up to 1.5 wt % Mn; and a remainder of Sn. A Snln solder alloy may consist of: 8 to 20 wt % In; optionally, one or more of: up to 12 wt % Bi, up to 4 wt % Ag, up to 5 wt % Sb, up to 3 wt % Cu, up to 2.5 wt % Zn, up to 1.5 wt % Ni, up to 1.5 wt % Co, up to 1.5 wt % Ge, up to 1.5 wt % P, and up to 1.5 wt % Mn; and a remainder of Sn.

Abstract: Implementations of the disclosure describe techniques for eliminating or reducing hot tearing in via-in-pad plated over (VIPPO) solder joints by incorporating an adhesive into a printed circuit board assembly (PCBA). In an embodiment, the adhesive is an adhesive containing fluxing agent that prevents tearing by reducing a differential in thermal expansion caused by a coefficient of thermal expansion (CTE) mismatch between a plated metal of the VIPPO pads and the PCB substrate.

Abstract: A lead-free solder preform includes a core layer and adhesion layer coated over surfaces of the core layer, where the preform delivers the combined merits from constituent solder alloys of the core and adhesion layers to provide both high temperature performance and improved wetting in high-temperature solder applications such as die attach. The core layer may be formed of a Bi Alloy having a solidus temperature above 260° C., and the adhesion layer may be formed of Sn, a Sn alloy, a Bi alloy, In, or an In alloy having a solidus temperature below 245° C. The solder preform may be formed using techniques such as: (1) electroplating a core ribbon with an adhesion material, (2) cladding an adhesion material foil onto a core ribbon, and/or (3) dipping a core ribbon in a molten adhesion alloy bath to allow thin layers of adhesion material to adhere to a core ribbon.

Abstract: 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.

Abstract: A braided solder wire rope includes a first alloy including Bi—Ag, Bi—Cu, Bi—Ag—Cu, or Bi—Sb; and the second alloy including Sn, In Sn—Ag, Sn—Cu, Sn—Ag—Cu, Sn—Zn, Bi—Sn, Sn—In, Sn—Sb or Bi—In, such that the second alloy controls an interface reaction chemistry with various metallization surface finish materials without interfering with a high temperature performance of the first alloy. The first alloy may have a solidus temperature around 258° C. and at least the first alloy of the first wire and the second alloy of the second wire may be braided together.

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

Abstract: Materials having increased mobility after heating are disclosed. In one particular exemplary embodiment, the materials may be realized as a material which has reduced apparent molecular weight and/or viscosity and thus increased mobility after a heating process, and which consequently allows material residue to be more easily removed during subsequent cleaning processes. Such a material may be useful in any industrial process which requires heating the material followed by removing material residue.

Abstract: A braided solder wire rope includes a first alloy including Bi—Ag, Bi—Cu, Bi—Ag—Cu, or Bi—Sb; and the second alloy including Sn, In Sn—Ag, Sn—Cu, Sn—Ag—Cu, Sn—Zn, Bi—Sn, Sn—In, Sn—Sb or Bi—In, such that the second alloy controls an interface reaction chemistry with various metallization surface finish materials without interfering with a high temperature performance of the first alloy. The first alloy may have a solidus temperature around 258° C. and at least the first alloy of the first wire and the second alloy of the second wire may be braided together.

Abstract: A sintering paste includes solvent and nanomicrocrystallite (NMC) particles. Each NMC particle is a single crystallite having at least one dimension in the range of 1 nm to 100 nm and at least one dimension in the range of 0.1 ?m to 1000 ?m. The sintering paste may be used in a pressureless sintering process to form a low porosity joint having high bond strength, high electrical and thermal conductivity, and high thermal stability.

Abstract: A lead-free solder alloy having a low melting temperature and low yield strength is disclosed. The solder alloy includes 5.0-20.0 wt. % of indium (In), 1.0-5.0 wt. % of silver (Ag), 0.25-2.0 wt. % of copper (Cu), 0.1-0.5 wt. % of zinc (Zn), and a remainder of tin (Sn). In implementations, a sulfur compound may be included in a concentration of 100 ppm to 500 ppm in the alloy to prevent oxidation of zinc and indium on the surface of the alloy. The solder alloy is particularly useful for but not limited to solder on pad applications in first level interconnect semiconductor device packaging.

Abstract: A sintering paste includes solvent and nanomicrocrystallite (NMC) particles. Each NMC particle is a single crystallite having at least one dimension in the range of 1 nm to 100 nm and at least one dimension in the range of 0.1 ?m to 1000 ?m. The sintering paste may be used in a pressureless sintering process to form a low porosity joint having high bond strength, high electrical and thermal conductivity, and high thermal stability.

Abstract: A lead-free solder wire includes a core wire with a first alloy and a shell coating layer with a second alloy. The first alloy may be composed of Bi—Ag, Bi—Cu, Bi—Ag—Cu, or Bi—Sb; and the second alloy may be composed of Sn, In Sn—Ag, Sn—Cu, Sn—Ag—Cu, Sn—Zn, Bi—Sn, Sn—In, Sn—Sb or Bi—In, such that the shell coating layer is applied to a surface of the core wire. In another implementation, the lead free solder wire may include a first wire with a first alloy and a second wire with a second alloy. The first alloy may be composed of Bi—Ag, Bi—Cu, Bi—Ag—Cu, or Bi—Sb; and the second alloy may be composed of Sn, Sn—Ag, Sn—Cu, Sn—Ag—Cu, Sn—Zn, Bi—Sn, Sn—In, Sn—Sb or Bi—In, such that the first alloy of the first wire and the second alloy of the second wire are braided together.

Abstract: A lead—free solder wire includes a core wire with a first alloy and a shell coating layer with a second alloy. The first alloy may be composed of Bi—Ag, Bi—Cu, Bi—Ag—Cu, or Bi—Sb; and the second alloy may be composed of Sn, In Sn—Ag, Sn—Cu, Sn—Ag—Cu, Sn—Zn, Bi—Sn, Sn—In, Sn—Sb or Bi—In, such that the shell coating layer is applied to a surface of the core wire. In another implementation, the lead free solder wire may include a first wire with a first alloy and a second wire with a second alloy. The first alloy may be composed of Bi—Ag, Bi—Cu, Bi—Ag—Cu, or Bi—Sb; and the second alloy may be composed of Sn, Sn—Ag, Sn—Cu, Sn—Ag—Cu, Sn—Zn, Bi—Sn, Sn—In, Sn—Sb or Bi—In, such that the first alloy of the first wire and the second alloy of the second wire are braided together.

Abstract: Methods and compositions are described for controlling bond line thickness of a joint formed during sintering. Spacer particles of a predetermined particle type and size are added in a predetermined concentration to a sintering paste to form a sintering paste mixture prior to sintering to achieve a targeted bond line thickness during sintering. The sintering paste mixture can be sintered under pressure and pressure-less process conditions. Under pressured sintering, the amount of pressure applied during sintering may be adjusted depending on the composition and concentration of the spacer particles to adjust bond line thickness.

Abstract: A lead-free solder alloy having a low melting temperature and low yield strength is disclosed. The solder alloy includes 5.0-20.0 wt. % of indium (In), 1.0-5.0 wt. % of silver (Ag), 0.25-2.0 wt. % of copper (Cu), 0.1-0.5 wt. % of zinc (Zn), and a remainder of tin (Sn). In implementations, a sulfur compound may be included in a concentration of 100 ppm to 500 ppm in the alloy to prevent oxidation of zinc and indium on the surface of the alloy. The solder alloy is particularly useful for but not limited to solder on pad applications in first level interconnect semiconductor device packaging.

Abstract: A solder paste consists of an amount of a first solder alloy powder between 44 wt % to less than 60 wt %; an amount of a second solder alloy powder between greater than 0 wt % and 48 wt %; and a flux; wherein the first solder alloy powder comprises a first solder alloy that has a solidus temperature above 260° C.; and wherein the second solder alloy powder comprises a second solder alloy that has a solidus temperature that is less than 250° C. In another implementation, the solder paste consists of an amount of a first solder alloy powder between 44 wt % and 87 wt %; an amount of a second solder alloy powder between 13 wt % and 48 wt %; and flux.

Abstract: A SnAgCuSb-based Pb-free solder alloy is disclosed. The disclosed solder alloy is particularly suitable for, but not limited to, producing solder joints, in the form of solder preforms, solder balls, solder powder, or solder paste (a mixture of solder powder and flux), for harsh environment electronics. An additive selected from 0.1-2.5 wt. % of Bi and/or 0.1-4.5 wt. % of In may be included in the solder alloy.

Abstract: Lead-free solder alloys and solder joints thereof with improved drop impact resistance are disclosed. In one particular exemplary embodiment, the lead-free solder alloys preferably contain 0.0-4.0 wt. % of Ag, 0.01-1.5 wt. % of Cu, at least one of the following additives: Mn in an amount of 0.001-1.0 wt. %, Ce in an amount of 0.001-0.8 wt. %, Y in an amount of 0.001-1.0 wt. %, Ti in an amount of 0.001-0.8 wt. %, and Bi in an amount of 0.01-1.0 wt. %, and the remainder of Sn.