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CN-121988929-A - SnSbNi solder for inhibiting Au embrittlement and application thereof

CN121988929ACN 121988929 ACN121988929 ACN 121988929ACN-121988929-A

Abstract

The invention relates to the field of electronic packaging and high-reliability TEC welding, and provides SnSbNi solder for inhibiting Au embrittlement and application thereof in TEC packaging welding, wherein the weight percentage of each component is 5-10% of Sb, 0.5-2% of Ni, the balance of Sn and the total amount of the components is 100%, in order to solve the problems in ensuring weldability and oxidation resistance by adopting a Ni/Au plating layer on a current TEC ceramic substrate. The SnSbNi solder overcomes the Au brittle defect, and after 10w cycles of temperature cycle reliability test, the resistance change rate of the device is less than 1 percent, and the device can still stably run.

Inventors

  • CUI BORAN
  • WU YONGQING
  • LI MING
  • TANG ZEFENG
  • LIU FENG

Assignees

  • 浙江先导热电科技股份有限公司

Dates

Publication Date
20260508
Application Date
20251205

Claims (10)

  1. 1. A SnSbNi solder for inhibiting Au embrittlement is characterized by comprising the following components, by weight, 5-10% of Sb, 0.5-2% of Ni, and the balance of Sn, wherein the total amount is 100%.
  2. 2. The SnSbNi solder for suppressing Au embrittlement according to claim 1, wherein the solder comprises 5 to 8% by weight of Sb, 0.8 to 1.2% by weight of Ni, and the balance Sn, totaling 100%.
  3. 3. Use of SnSbNi solder for inhibiting Au embrittlement as claimed in claim 1 or 2 in TEC package soldering.
  4. 4. Use of SnSbNi solder for Au embrittlement suppression in TEC package soldering according to claim 3, wherein the TEC joint structure package soldering process is the following steps: a) Plating a Ni layer on the surface of the Cu layer of the end face of the welded TEC ceramic, and then plating an Au layer on the surface of the Ni layer; b) The 2 end surfaces of the thermoelectric arm are respectively plated with a Ni layer and an Au layer on the surfaces in turn; c) SnSbNi solder is arranged between the Au layer of the thermoelectric arm and the Au layer of the end face of the TEC ceramic, and the pressure of 0.1-0.3MPa is applied; d) Heating to 250-270 ℃ in protective atmosphere, preserving heat for 10-30s, and cooling to finish welding.
  5. 5. Use of SnSbNi solder for Au embrittlement suppression in TEC package soldering according to claim 4, wherein the surface plating is selected from electroless plating or electroplating.
  6. 6. The use of SnSbNi solder for inhibiting Au embrittlement in TEC package soldering according to claim 4, wherein the surface Ni plating layer thickness in steps a) and b) is 3-7 μm and the Au layer thickness is 0.05-1 μm.
  7. 7. Use of SnSbNi solder for inhibiting Au embrittlement in TEC package soldering according to claim 4, wherein the solder layer thickness in step c) is 40-60 μm.
  8. 8. The use of SnSbNi solder for inhibiting Au embrittlement in TEC package soldering according to claim 4, wherein in step d) the temperature is raised to 250-270 ℃ at 3-5 ℃ per s, and after 10-30s incubation, the solder is cooled to room temperature at 2-4 ℃ per s.
  9. 9. Use of SnSbNi solder for inhibiting Au embrittlement in TEC package soldering according to claim 4, wherein the protective atmosphere in step d) is N 2 or a formic acid reducing atmosphere.
  10. 10. The application of SnSbNi solder for inhibiting Au embrittlement in TEC package soldering of claim 4, wherein the TEC joint structure package soldering process is to solder the upper and lower ceramic substrates with the two ends of the thermoelectric arm respectively into a whole through the soldering layer.

Description

SnSbNi solder for inhibiting Au embrittlement and application thereof Technical Field The invention relates to the field of electronic packaging and high-reliability TEC (thermal-Electric Cooler) welding, in particular to SnSbNi solder for inhibiting Au embrittlement and application thereof in TEC packaging welding. Background The TEC semiconductor cooler (Thermo Electric Cooler) is fabricated using the peltier (Peliter) effect of semiconductor materials. The peltier effect is a phenomenon in which when a direct current passes through a couple of two semiconductor materials, heat is absorbed at one end and released at the other end of the couple, and therefore TEC is also called a thermoelectric cooler. Due to the advantages of no noise, no vibration, no refrigerant, small size, light weight and the like, the TEC ceramic substrate commonly adopts a Ni/Au coating to ensure weldability and oxidation resistance. However, conventional Sn-based solders are prone to react with Au during soldering to form a continuous brittle phase of AuSn 4、（Au,Ni）Sn4, resulting in reduced joint shear strength, poor temperature cycling reliability, and failure of the basic 3w cycle device. The existing solution mainly comprises 1) tin-coating/tin-absorbing gold removal before welding, which is complicated in process, high in cost and easy to damage a thin plating layer, 2) micro-Ni-containing solder such as SAC305, which has limited effect on Au embrittlement inhibition, and 3) Ni diffusion promotion by improving the reflow peak temperature, wherein the TEC ceramic is resistant to temperature less than or equal to 300 ℃, and the temperature is too high, so that warping and cracking are easy to generate. Therefore, there is a need for a novel solder and a mating soldering process that can be achieved at temperatures less than or equal to 270 ℃ and that can suppress Au embrittlement without gold removal. CN106757221A discloses a method for selectively preparing gold-tin eutectic solder on the surface of a ceramic substrate, which comprises the following steps of (1) plating a metal layer on the ceramic substrate by a physical method or an electrochemical method, (2) processing the metal layer by a photoetching technology to obtain a pattern layer, (3) etching the metal layer by using a metal etching solution to obtain a patterned metal layer, (4) electrodepositing gold-tin alloy on the patterned metal layer to form solder, wherein the gold-tin alloy electroplating solution adopted by electrodeposition is cyanide-free electroplating solution comprising gold salt, tin salt, a brightening agent, a complexing agent and an antioxidant. The gold-tin eutectic solder prepared by the method can be electrodeposited at a designated position to obtain a gold-tin alloy plating layer with bright and compact surface, the thickness of the gold-tin eutectic salient point is controllable, different packaging requirements can be met, the melting point of the formed eutectic alloy is 280 ℃ plus or minus 0.2 ℃, good welding performance and oxidation resistance are achieved, but the process is complex, and the cost is high. Disclosure of Invention In order to solve the problems in the prior art that the TEC ceramic substrate adopts a Ni/Au coating to ensure the weldability and the oxidation resistance, the invention provides SnSbNi solder for inhibiting Au embrittlement and application thereof in TEC package welding, which are applicable to SnSbNi solder of the Ni/Au coating TEC and a welding process, overcome Au embrittlement, and the device resistance change rate is less than 1% after 10w cycles of temperature cycle reliability test, and can still stably run. The SnSbNi solder for inhibiting Au embrittlement comprises, by weight, 5-10% of Sb, 0.5-2% of Ni, and the balance of Sn, wherein the total amount is 100%. Preferably, the weight percentage of Sb is 5-8%, the weight percentage of Ni is 0.8-1.2%, and the balance of Sn is 100%. Preferably, the content of unavoidable impurities in the solder is less than or equal to 0.05%. The application of SnSbNi solder for inhibiting Au embrittlement in TEC package soldering, in which TEC is widely used as a precision temperature control system in the industrial fields of optical communication and medical equipment, and in which TEC can maintain a stable reaction temperature or realize rapid temperature change, bidirectional current control is required to realize heating and cooling and more efficient temperature control, the TEC joint structure package soldering process comprises the following steps: a) Plating a Ni layer with the thickness of 3-7 mu m on the surface of the Cu layer of the end face of the welded TEC ceramic, and then plating an Au layer with the thickness of 0.05-1 mu m on the surface of the Ni layer; Preferably, the surface plating is selected from electroless plating or electroplating. B) The 2 end surfaces of the thermoelectric arm are respectively plated with a Ni layer of 3-7 mu m and an Au