Search

CN-121997887-A - Method for predicting growth of metal compound of leadless micro-interconnection structure under temperature cycle

CN121997887ACN 121997887 ACN121997887 ACN 121997887ACN-121997887-A

Abstract

The invention discloses a metal compound growth prediction method of a lead-free micro-interconnection structure under a temperature cycle, which comprises the steps of establishing a functional relation between the heat diffusion net flux of target metal atoms in the lead-free micro-interconnection structure and the layer thickness growth rate of a metal compound layer, further establishing a functional relation between the thickness growth rate and the heat diffusion coefficient of the target metal atoms, establishing a functional relation between the heat diffusion coefficient of the target metal atoms along with the change of temperature, obtaining a thickness growth rate expression taking the temperature as a variable according to the functional relation between the heat diffusion coefficient along with the change of temperature and the functional relation between the thickness growth rate and the heat diffusion coefficient, and obtaining the thickness growth quantity of the metal compound layer in a single temperature cycle period by carrying out time integration on the thickness growth rate expression taking the temperature as the variable. The method can effectively realize the growth prediction of the lead-free micro-interconnection interface metal compound under the temperature cycle working condition.

Inventors

  • FU ZHIWEI
  • Wei Qinru
  • LIU LUCHUAN
  • YU HAO
  • CHEN YIQIANG
  • LU GUOGUANG

Assignees

  • 中国电子产品可靠性与环境试验研究所（（工业和信息化部电子第五研究所）（中国赛宝实验室））

Dates

Publication Date
20260508
Application Date
20260330

Claims (9)

  1. 1. The method for predicting the growth of the metal compound of the leadless micro-interconnection structure under the temperature cycle is characterized by comprising the following steps of: S1, determining target metal atoms according to the type of an interface metal compound layer in a lead-free micro-interconnection structure, establishing a functional relation between the thermal diffusion net flux of the target metal atoms and the thickness growth rate of the metal compound layer, and further establishing a functional relation between the thickness growth rate of the metal compound layer and the thermal diffusion coefficient of the target metal atoms; step S2, based on an atomic diffusion theory and an Arrhenius equation, establishing a functional relation of a target metal atomic thermal diffusion coefficient along with temperature change; Step S3, obtaining a layer thickness growth rate expression of the metal compound with temperature as a variable according to the functional relation of the target metal atom thermal diffusion coefficient established in the step S2 along with the temperature change and the functional relation of the layer thickness growth rate of the metal compound established in the step S1 and the target metal atom thermal diffusion coefficient; And S4, obtaining the thickness growth quantity of the metal compound layer in different temperature change stages in a single temperature cycle period by time integration of a metal compound layer thickness growth rate expression taking temperature as a variable, and realizing the thickness growth prediction of the metal compound layer in a plurality of temperature cycle periods by accumulation calculation.
  2. 2. The method of claim 1, wherein the lead-free micro-interconnect structure comprises a Cu pad, a Cu 3 Sn layer, a Cu 6 Sn 5 layer, and a Sn solder, wherein the metal compound layers are Cu 6 Sn 5 and Cu 3 Sn layers and the target metal atom is Cu.
  3. 3. The method according to claim 2, wherein in step S1, a net heat diffusion flux of Cu atoms is established as a function of the Cu 6 Sn 5 layer and the Cu 3 Sn layer thickness growth rate: Wherein, the And Represents the concentration of Cu atoms in the Cu 3 Sn layer and the Cu 6 Sn 5 layer respectively, And The thicknesses of the Cu 3 Sn layer and the Cu 6 Sn 5 layer are shown respectively, And The thickness growth rates of the Cu 3 Sn and Cu 6 Sn 5 layers, respectively; 、 And The Cu atomic heat diffusion fluxes of the Cu bond pad to the Cu 3 Sn layer, the Cu 3 Sn layer to the Cu 6 Sn 5 layer and the Cu 6 Sn 5 layer to the Sn solder are represented respectively, For a net heat diffusion flux of Cu atoms in the Cu 3 Sn layer, Net flux for thermal diffusion of Cu atoms in Cu 6 Sn 5 layer: Wherein, the For the Cu atomic concentration in the Cu pad, To dissolve the concentration of Cu atoms in Sn solder, And The thermal diffusivity of Cu atoms in the Cu 3 Sn layer and the Cu 6 Sn 5 layer, respectively.
  4. 4. A method according to claim 3, wherein in step S2, the thermal diffusivity of Cu atoms as a function of temperature is: , , Wherein, the And Constant factors of thermal diffusivity of Cu atoms in the Cu 3 Sn layer and the Cu 6 Sn 5 layer respectively, And The diffusion activation energy, which is the thermal diffusion coefficient of Cu atoms in the Cu 3 Sn layer and the Cu 6 Sn 5 layer, respectively, R is the gas constant and T is the kelvin temperature.
  5. 5. The method of claim 4, wherein in step S3, the thickness growth rate expression of the Cu 3 Sn layer and the Cu 6 Sn 5 layer as a temperature variable is: Wherein A and B are constants, 。
  6. 6. The method of claim 5, wherein in step S4, the thickness growth amounts of the Cu 6 Sn 5 layer and the Cu 3 Sn layer obtained by time integration are: Wherein t is time.
  7. 7. A computer device comprising a memory, a processor and a computer program stored on the memory, characterized in that the processor executes the computer program to carry out the steps of the method of any one of claims 1-6.
  8. 8. A computer readable storage medium, on which a computer program is stored, characterized in that the computer program, when being executed by a processor, carries out the steps of the method according to any one of claims 1-6.
  9. 9. A computer program product comprising a computer program, characterized in that the computer program, when being executed by a processor, implements the steps of the method according to any of claims 1-6.

Description

Method for predicting growth of metal compound of leadless micro-interconnection structure under temperature cycle Technical Field The invention belongs to the field of chip packaging, and particularly relates to a metal compound growth prediction method of a lead-free micro-interconnection structure under temperature cycling. Background As the chip process approaches physical limits, micro-interconnects in advanced packaging become critical in determining reliability, and lead-free micro-interconnects are becoming mainstream due to their environmental protection and process maturity. However, lead-free solders react with base metals (e.g., cu, ni) during service to form brittle intermetallic compounds (e.g., cu 6Sn5、Cu3 Sn), which overgrowth can lead to interfacial embrittlement, voids and cracks, severely impairing the mechanical integrity of the interconnect and fatigue resistance. The prior art realizes the growth prediction of the interface metal compound layer in the micro-interconnection structure from the angles of high temperature stress, thermoelectric coupling stress and the like, and is an important method for evaluating the reliability of the micro-interconnection. However, the technical solutions in the prior art are all based on constant stress conditions for analysis, i.e. it is assumed that the loading parameters such as high temperature, current density, etc. remain unchanged during service. In practical application scenarios, the chip often undergoes frequent switching on and off or power fluctuation, and the thermal load borne by the interface atoms is periodically changed due to the temperature cycle stress generated by the chip. Under the temperature circulation condition, the atomic diffusion flux changes in real time along with the temperature, the related key parameters such as diffusion coefficient and the like are not constant any more, the growth dynamics behavior of the metal compound has obvious difference from the growth dynamics behavior of the metal compound under constant stress, the existing growth prediction model can not reflect the dynamic influence of the periodic temperature change on the atomic migration rule, the growth prediction of the interface metal compound under the temperature circulation working condition can not be effectively realized, and the actual service life of the micro-interconnection under the complex thermal load is difficult to accurately evaluate. Therefore, there is a need to establish a lead-free micro-interconnect interface metal compound growth prediction method suitable for temperature cycling conditions. Disclosure of Invention The invention aims to provide a metal compound growth prediction method of a lead-free micro-interconnection structure under a temperature cycle, computer equipment, a computer readable storage medium and a computer program product, which can effectively realize the metal compound growth prediction of a lead-free micro-interconnection interface under a temperature cycle working condition. In order to achieve the above object, an aspect of the present invention provides a method for predicting growth of a metal compound of a lead-free micro interconnect structure under a temperature cycle, comprising: S1, determining target metal atoms according to the type of an interface metal compound layer in a lead-free micro-interconnection structure, establishing a functional relation between the thermal diffusion net flux of the target metal atoms and the thickness growth rate of the metal compound layer, and further establishing a functional relation between the thickness growth rate of the metal compound layer and the thermal diffusion coefficient of the target metal atoms; step S2, based on an atomic diffusion theory and an Arrhenius equation, establishing a functional relation of a target metal atomic thermal diffusion coefficient along with temperature change; Step S3, obtaining a layer thickness growth rate expression of the metal compound with temperature as a variable according to the functional relation of the target metal atom thermal diffusion coefficient established in the step S2 along with the temperature change and the functional relation of the layer thickness growth rate of the metal compound established in the step S1 and the target metal atom thermal diffusion coefficient; And S4, obtaining the thickness growth quantity of the metal compound layer in different temperature change stages in a single temperature cycle period by time integration of a metal compound layer thickness growth rate expression taking temperature as a variable, and realizing the thickness growth prediction of the metal compound layer in a plurality of temperature cycle periods by accumulation calculation. Another aspect of the invention provides a computer device comprising a memory, a processor and a computer program stored on the memory, the processor executing the computer program to carry out the steps of the method described above