How is a high quality solder sphere made?

Due to the tiny size of sol­der balls and the fact that there can be hun­dreds or even thou­sands of sol­der balls used on a sin­gle device, cus­tomers not only expect, but demand high qual­i­ty sol­der spheres. So what exact­ly deter­mines a high qual­i­ty sol­der sphere? Sol­der ball qual­i­ty is deter­mined by a num­ber of fac­tors.

High Quality Solder Spheres Available from CAPLINQ
High Qual­i­ty Sol­der Spheres Avail­able from CAPLINQ

Sol­der Sphere (Ball) Qual­i­ty Fac­tors:

Advanced Solder Sphere Smelting Alloy Technology for High Alloy Composition Accuracy

There is a lot of tech­nol­o­gy that goes into a prop­er smelt­ing tech­nique. In order to get a prop­er sol­der alloy, it means that you have to start with each of the spe­cif­ic met­als and melt them togeth­er to get the spe­cif­ic tin-lead sol­der alloys of Sn63Pb37 or lead free com­bi­na­tions of SAC305 sol­der balls (96.5% Sn, 3.0% Ag, 0.5% Cu) or any oth­er of our lead free sol­der offer­ings includ­ing SAC105, SAC125N, SAC305, SAC387, SAC396 or SAC405. Obvi­ous­ly, before they are smelt­ed there is some between or inter­im peri­od that the met­als are not prop­er­ly mixed.

Unless this process is opti­mized, there will be alloy seg­re­ga­tion in which you will have mul­ti­ple peaks. It is obvi­ous if there is not seg­re­ga­tion of the alloy issue if we can see the dis­tinct peaks that we are aim­ing for.

Example of Alloy with and without segregation
Exam­ple of Alloy with and with­out seg­re­ga­tion

High Solder Sphere Process Capability Index Cpk

What you want to be able to show with your sol­der ball pro­duc­tion process is that it not only uni­form with a tight diam­e­ter and spher­oid tol­er­ance, but that it is also repeat­able from one batch to the next. The way to mea­sure this, is to mea­sure not only the sol­der ball to ball vari­abil­i­ty but then also the batch to batch vari­abil­i­ty of the sol­der sphere pro­duc­tion. An impor­tant mea­sure of this is the process capa­bil­i­ty index or Cpk. Our process ensures a Cpk of at least 1.33 and is cur­rent­ly above 1.67.

CAPLINQ has a process capability index (Cpk) of at least 1.33 and is currently above 1.67.
CAPLINQ has a process capa­bil­i­ty index (Cpk) of at least 1.33 and is cur­rent­ly above 1.67.

Advanced Solder Ball Forming Technology

The con­ven­tion­al method of mak­ing sol­der spheres is to start with a sol­id sol­der alloy. Whether the alloy is a Sn63Pb37 or a Lead-free sol­der, it is first drawn out into a sol­der wire, or formed into a sol­der sheet. In sol­der wire form, the wire is cut very small and from the sol­der foil, tiny spec­i­men are punched. These tiny sol­der pieces (they are not yet sol­der balls), are put into a hot oil which melts them and imme­di­ate­ly cre­ates a sol­der sphere or sol­der ball as we know them. The balls then con­tin­ue to fall into cool­er oil where they solid­i­fy as sol­der balls.

This prac­tice is still very com­mon with low end sup­pli­ers as it is a known, inex­pen­sive process. There are many issues with this process how­ev­er:

  • Though the weight of the balls is known, there is still a lot of vari­a­tion in the weight of each sol­der sphere
  • There is no way you will get the sol­der sphere tol­er­ance of 1.5% that CAPLINQ guar­an­tees on its sol­der spheres
  • This process is messy and prone to con­t­a­m­i­na­tion and impu­ri­ties
  • It is much slow­er than the state-of-the-art advanced uni­form droplet spray­ing tech­nol­o­gy

The sol­der spheres CAPLINQ offers are made using an advanced tech­nol­o­gy uni­form droplet spray­ing. This process begins already with a molten met­al alloy, whether it be Tin/Lead or a Lead­free sol­der alloy. Kept in an inert nitro­gen atmos­phere, the sol­der alloy is then blown through an ori­fice into again anoth­er nitro­gen envi­ron­ment through either a 3‑orifice or 6‑orifice design. Here’s the dif­fer­ence:

  • 3‑Orifice Design: This is the con­ven­tion­al design by man­u­fac­tur­ers who are still using old­er equip­ment to pro­duce sol­der spheres. This design pro­duces high qual­i­ty sol­der spheres, and each ori­fice can pro­duce up 7,000 sol­der spheres per sec­ond per ori­fice, which means the entire design pro­duces up to 21,000 sol­der spheres per sec­ond or 75.6 mil­lion spheres per hour.
  • 6‑Orifice Design: CAPLIN­Q’s sol­der spheres are pro­duced using state-of-the-art 6‑orifice designs. This design pro­duces the same high qual­i­ty sol­der spheres but dou­ble the sol­der sphere out­put to 42,000 sol­der balls per sec­ond or a total of 151.2 mil­lion sol­der spheres per hour.
6-orifice design produces 42,000 solder spheres per second, or 151.2 million solder spheres per hour.
6‑orifice design pro­duces 42,000 sol­der spheres per sec­ond, or 151.2 mil­lion sol­der spheres per hour.

Smart Packaging Practices

Sol­der spheres can oxi­dize. You can read this arti­cle on sol­der ball oxi­da­tion, but let it be known that pack­ag­ing can go a long, long way to reduce oxi­da­tion and do ensure that your sol­der spheres have a long shelf-life — in many cas­es beyond the expi­ra­tion date — sim­ply by keep­ing the sol­der spheres sealed in their orig­i­nal pack­ag­ing. CAPLINQ pack­ages most of its sol­der spheres in quan­ti­ties of 250,000 pieces. The rea­son why is that after pro­duc­tion, the sol­der spheres are imme­di­ate­ly pack­aged and sealed in nitro­gen. Once the jar is unsealed, and opened the nitro­gen is gone, and there is no more inert blan­ket to pro­tect them.

Some man­u­fac­tur­ers and specif­i­cal­ly some sol­der ball dis­trib­u­tors buy large quan­ti­ties of sol­der spheres in few jars and then repack the sol­der spheres into jars with few­er quan­ti­ties. We have done our home­work, and dis­cussed with many cus­tomers, and they agree that the 250,000 sol­der spheres per jar is the right bal­ance of num­ber of pieces to num­ber of jars. That’s why every jar you receive from CAPLINQ will be sealed. It’s your way of know­ing that the nitro­gen is packed right inside.

CAPLINQ sup­plies a range of sol­der spheres includ­ing Tin/Lead (Sn63Pb37) Sol­der Spheres or our Lead­free (Pb-free) Sol­der Spheres includ­ing SAC105, SAC125N, SAC305, SAC387, SAC396 or SAC405 and 4N Pure Tin Sn100 Sol­der Spheres.

We also now offer Bi58Sn42 Eutec­tic Lead­free Sol­der Spheres and Bi57Sn42Ag1 Near-Eutec­tic Lead­free Sol­der Spheres. You can also con­tact us if you have fur­ther ques­tions on buy­ing sol­der balls.

About Chris Perabo

Chris is an energetic and enthusiastic engineer and entrepreneur. He is always interested in taking highly technical subjects and distilling these to their essence so that even the layman can understand. He loves to get into the technical details of an issue and then understand how it can be useful for specific customers and applications. Chris is currently the Director of Business Development at CAPLINQ.

4 thoughts on “How is a high quality solder sphere made?

  1. We are inter­est­ed in pur­chas­ing sol­der ball cop­per-tin (75/25)
    Th alloy has:-
    Tin 20%
    Nick­el 5%
    Allu­mini­um 3%
    Cop­per 71%
    Balls of dia 2.25mm wt about 130-Mgms
    Qty 500,000 pcs per month
    We can also take wire of 2.50mm dia

  2. Hur­rah! After all I got a blog from where I be capa­ble of
    in fact get valu­able data con­cern­ing my study and knowl­edge.

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