Although the practice of soldering has been around for thousands of years, current soldering processes are often state-of-the-art and require the best materials for consistent, reliable, and void-free solder joints.

Solder Features & Benefits

Soldering is a process that creates electrical, mechanical, or thermal bonds using heat, filler material, and flux. The heat reflows the filler material and the flux cleans the oxides off the surfaces that will be joined together. Once the heat is removed, the solder solidifies to create a bond. Although this sounds simple, there are many things to consider when choosing the right materials for your process.

Considerations for choosing your solder alloy:

  • What is the operating temperature of your end product?
  • What temperature constraints do you have in your process (components, substrates, etc.)?
  • What are your substrate metallizations?
    • Au, Ag, or Ni plating
    • HASL
    • ENIG
    • Immersion Sn or Immersion Ag
    • OSP
    • Molded interconnect device materials (MID)
  • What solder form does your current process support (solder paste, solder preforms, solder wire, etc.)?
  • What is your reflow process?
    • Standard reflow oven
    • Laser
    • Induction
    • Hand held soldering iron
    • Convection oven
  • Do you have any environmental concerns?
    • Pb-free
    • REACH
    • RoHS

Considerations for removing oxides:

Once you have chosen the right solder, you need to consider what method you will use to remove the oxides to encourage the solder to wet to the surface.

These considerations include:

  • What process environment will you use?
    • Nitrogen or some other reducing environment
    • Flux-free process
    • Air reflow
  • How strong are the oxides you need to remove?
  • What other environmental factors should you consider?
    • Are you using a water-wash or no-clean process?
    • Do you have to be concerned with the halide-content of your soldering materials?
SnPb Bar Solder

Bar Solder

Indium Corporation manufactures high quality, very low oxide content, extruded bar solder for wave, fountain, and dip soldering applications. We use only "conflict-free" grade A tin, per ASTM B32.

Our bar solder alloy composition and purity meets, or exceeds, the requirements of ASTM B32, IPC J-STD-006, and JIS Z 3282, as well as all other similar industry and customer specifications.

Bar Solder Chips are also available and are commonly used to fill smaller solder pots or to quicken the melting of solder in a new solder pot. The greater surface area of the chips allows for better heat transfer between the solder pot and the metal.

Products for Laser and Optical Packaging

Gold Solders

Indium Corporation is a leading joining and bonding materials innovator for medical, aerospace, optoelectronics, and automotive applications. When even 10 ppm of contamination can cause process and application failures – quality counts. Indium Corporation casts our alloys, which enables us to closely control the process from start to finish and ensure purity.



During the soldering process, the copper does not melt, ensuring that the bondline is maintained across the entire solder joint. This results in:

  • Improved mechanical and thermal reliability
  • Uniform bondline thickness
  • Low-voiding performance
MC Ingots

Solder Alloys

Since our founding in 1934, Indium Corporation has been the world’s leader in specialty solders and alloy development. Our R&D staff, including several Ph.D. metallurgists, work with our core set of metals to develop alloys that will address the latest soldering and sealing challenges.

Our alloy selection is based on decades of listening to our customers and finding solutions that enable cutting-edge technologies. Melting temperature ranges from 7-1,064°C.

There are six main alloy families:

Solder Paste

Solder Paste

Indium Corporation’s high quality solder pastes are uniquely formulated for superior performance to satisfy a variety of assembly requirements. Powders are available in hundreds of alloys and sizes from Type 3-7, including Type 5MC, Type 6SG, and Type 7SG. Solder pastes can be made from these powders using a wide variety of flux vehicles to achieve the best results for your applications. Specialized pastes are available for printing, dipping, dispensing, and pin transfer assembly.

Solder Preforms

Solder Preforms

Solder Preforms are used in a variety of applications that require precise amounts of solder.

Solder Preforms come in standard shapes such as squares, rectangles, washers and discs. Typical sizes range from .010" (.254mm) up to 2" (50.8mm). Smaller and larger sizes, as well as custom shapes, are also available. Dimensions can be held to tight tolerances to assure volume accuracy.

Selecting Alloys

A wide assortment of alloys is available in liquidus temperatures that range from 47°C to 1063°C. Alloys can be indium-contained, gold-contained, lead-free, fusible or standard tin-lead, as well as many others.

  1. Alloy selection should be based on strength and other required physical properties, as well as the preferred soldering temperature and the operating temperature of the device being soldered. A general rule is to select an alloy that melts at least 50°C higher than the operational temperature of the part being soldered.
  2. Next, consider the materials being soldered and what solder is most compatible with them. For example, tin-based solders will scavenge the gold from gold-plated parts, forming brittle intermetallics, so indium-based solders are generally recommended in these cases.
  3. Metals and alloys have different characteristics that can affect the ease with which they can be made into different shapes and thicknesses. It is important to consider the shape of the final preform in the alloy selection process.
  4. The operating environment of the completed assembly is also an important consideration for alloy selection. Will it operate in very high or very low temperatures, or be subjected to vibration? If so, you need to select an alloy that will stand up to these conditions.

Our Application Engineers will work with you to determine the best alloy for your application.

Ribbon and Foil

Solder Ribbon

High quality Solder Ribbon and Foil manufactured by Indium Corporation is available in many standard alloys and sizes. Material can also be custom made to your unique material and dimensional requirements.

Solder Ribbon is supplied in continuous lengths and is packaged on spools. Solder Foil is supplied in sheet form.

Ribbon Dimensions

Whether you are looking for large quantities of Solder Ribbon in specific widths and thicknesses for automatic die bonding, or a few feet to do testing, Indium Corporation can accommodate your needs.

Our capabilities allow us to manufacture widths as small as .020" (.5mm) and up to 3" (76mm). Thicknesses range from .001" (.025mm) up to as thick as your application requires. All dimensions are dependent on the properties of the metals involved.

We can work with you on your specific dimensional requirements.

Solder Spheres

Specialty Solder Spheres

Indium Corporation is a supplier of specialty solder and brazing spheres in small to mid-size volumes. We offer a wide variety of alloys and sizes from around 0.004” (100 microns) to 0.078” (1.98mm), depending on the alloy. Melting points range from below 90°C to over 700°C.

We supply many of the leading suppliers of medical, transportation and automotive, military and aerospace, high-end mobile devices, and computing equipment. Our customers come to us because we can supply consistently high-quality materials for precision assembly challenges.

Solder Research Kit

Solder Research Kits

Indium Corporation understands the challenges of developing products for today's marketplace and the need to test options quickly and efficiently. One of the key hurdles in product development is being able to test a variety of options at a reasonable cost. Indium Corporation Solder Research Kits offer a range of options so you can customize your kit to meet your requirements.

In addition, we have the technical expertise to help you select just the right materials for your kit.