Method for analyzing reliability and failure mechanism of advanced heterogeneous integrated hybrid bonding interconnection
By simulating the electromigration process within the interconnect and combining it with the contact resistance at the bonding interface, the reliability and failure mechanism of advanced heterogeneous integrated hybrid bonding interconnects are analyzed. This solves the problem of the lack of analytical methods in the existing technology and enables effective prediction and design guidance for interconnect reliability.
Patent Information
- Application Number
- CN202510883252.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-28
- Publication Date
- 2025-10-21
AI Technical Summary
Existing technologies lack methods for analyzing the reliability and failure mechanisms of advanced heterogeneous integrated hybrid bonding interconnects. The contact resistance at the bonding interface affects the electric field distribution, which in turn affects heat conduction, mechanical stress, and vacancy migration, making interconnect reliability design difficult.
Numerical methods are used to simulate the electromigration process within interconnects. Combined with the contact resistance at the bonding interface, the equations for current continuity, heat conduction, solid mechanics, and vacancy diffusion are solved in a coupled manner to analyze interconnect reliability and failure mechanisms, including calculation of contact resistance at the bonding interface, current distribution, temperature distribution, stress distribution, and vacancy concentration.
It can effectively predict the evolution of contact resistance at the bonding interface under different process conditions and its impact on interconnect reliability, guide the reliability design of interconnects, and improve the reliability analysis capability of interconnect structures.
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Figure CN120822329A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of multi-physics field modeling and simulation of nanoelectronic devices, and relates to a method for analyzing the reliability and failure mechanism of advanced heterogeneous heterogeneous integrated hybrid bonding interconnections. Background Art
[0002] The construction of interconnect structures for three-dimensional heterogeneous integrated circuits based on advanced heterogeneous heterogeneous integrated circuit hybrid bonding technology has become one of the key technologies in the current chip manufacturing field. Compared with traditional soft soldering processes, this technology can achieve interconnect structures with narrow pitch, low latency and high reliability. The schematic diagram of the three-dimensional heterogeneous integrated circuit and the cross-sectional view of the bonding structure are shown in Figure 2. Figure 1 However, as the size of interconnects in 3D heterogeneous integrated circuits decreases, the electromigration effect in the interconnects becomes more and more serious because the geometric structure of the interconnects constrains the current path and thus amplifies the electron wind force.
[0003] In recent years, systematic research has been carried out at home and abroad on the vacancy migration mechanism of interconnect structures in three-dimensional heterogeneous integrated circuits (H.Ceric, H.Zahedmanesh, K.Croes, R.Lacerda de Orio and S.Selberherr, "Electromigration-induced void evolution and failure of Cu / SiCN hybrid bonds," Journal of Applied Physics, 2023). Based on the experimental study, the effects of bond joint shape, bond spacing, bond misalignment and bonding process conditions on interconnect reliability were studied. In addition, the contact resistance at the bond interface is an important factor affecting the reliability of the interconnect. The resistance elements in the bonded interconnect and the microstructure of the bond interface, such as Figure 2 The contact resistance is caused by imperfect interfacial contact due to surface roughness, impurities, and metal oxidation during the bonding process (HL Leong, CLGan, RI Made, CVT Thompson, KLPey and HY Li, "Experimental characterization and modeling of the contact resistance of Cu–Cu bonded interconnects," Journal of Applied Physics, 2009).
[0004] However, a method for analyzing the reliability and failure mechanisms of hybrid bonded interconnects for advanced heterogeneous heterogeneous integration is still lacking. The contact resistance at the bonding interface can alter the electric field distribution, which in turn affects thermal conduction, mechanical stress, and vacancy migration, resulting in complex effects on vacancy evolution in the interconnect. Therefore, it is necessary to develop a method for analyzing the reliability and failure mechanisms of hybrid bonded interconnects for advanced heterogeneous heterogeneous integration. This method can study the influence of bonding process conditions on vacancy evolution in bonded interconnects, clarify the underlying mechanisms, and guide interconnect reliability design.
[0005] Based on this, the present invention proposes a method for analyzing the reliability and failure mechanism of advanced heterogeneous heterogeneous integrated hybrid bonding interconnections, thereby guiding interconnection design. Summary of the Invention
[0006] In view of the shortcomings of the existing technology, the present invention provides a method for analyzing the reliability and failure mechanism of advanced heterogeneous heterogeneous integrated hybrid bonding interconnections.
[0007] The technical solution adopted in the present invention is as follows:
[0008] A method for analyzing reliability and failure mechanisms of hybrid bonding interconnects for advanced heterogeneous heterogeneous integration includes the following steps:
[0009] 1) Calculate the contact resistance of the bonding interface based on the advanced heterogeneous heterogeneous integrated hybrid bonding process conditions;
[0010] 2) Using the bond interface contact resistance as the input for electromigration simulation, a numerical method is then used to simulate the multi-physics process of vacancy evolution induced by electromigration within the interconnect.
[0011] 3) Analyze interconnection reliability and failure mechanism based on simulation results.
[0012] In the above technical solution, further, the process conditions described in step 1) include bonding pressure, material type, and surface roughness of the bonding interface.
[0013] Furthermore, in step 1), the contact resistance at the interconnection bonding interface is calculated using the Mikic elastic relationship.
[0014] Furthermore, the electromigration simulation described in step 2) includes coupled solution of the current continuity equation, the heat conduction equation, the solid mechanics equilibrium equation, and the vacancy diffusion equation, and the bonding interface contact resistance is considered when solving the current continuity equation.
[0015] Furthermore, the analysis of interconnect reliability and failure mechanism described in step 3) includes at least one of the following: (a) analyzing the change of interconnect resistance over time under different bonding interface contact resistances; (b) analyzing the current distribution within the interconnect under different bonding interface contact resistances; (c) analyzing the temperature distribution within the interconnect under different bonding interface contact resistances; (d) analyzing the stress distribution within the interconnect under different bonding interface contact resistances; (e) analyzing the vacancy concentration and vacancy diffusion flux within the interconnect under different bonding interface contact resistances; and (f) analyzing the vacancy nucleation position within the interconnect under different bonding interface contact resistances.
[0016] Compared with the prior art, the present invention has at least the following beneficial effects:
[0017] This paper provides a method for analyzing the reliability and failure mechanisms of hybrid bonding interconnects in advanced heterogeneous heterogeneous integration. This method integrates the advanced heterogeneous heterogeneous integration hybrid bonding process model with the interconnect electromigration model. This method effectively predicts the evolution of the bond interface contact resistance under different process conditions and its impact on interconnect reliability, thereby guiding interconnect reliability design. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 (a) Schematic diagram of the 3D heterogeneous integrated circuit structure; (b) Schematic diagram of the interconnect bonding cross section.
[0019] Figure 2 (a) The resistance of the interconnect, including the resistance of the copper conductor (R trace ) and the contact resistance at the bonding interface (R contact ); (b) Schematic diagram of the interconnect bonding interface microstructure that induces contact resistance.
[0020] Figure 3 (a) Schematic diagram of interconnect bonding; (b) schematic diagram of interconnect bonding cross-section structure; (c) boundary condition setting for interconnect bonding electromigration simulation.
[0021] Figure 4 The void nucleation locations within the interconnect at different contact resistances.
[0022] Figure 5 The potential distribution inside the interconnect under different contact resistances.
[0023] Figure 6 Temperature distribution inside the interconnect at different contact resistances.
[0024] Figure 7 Vacancy concentration distribution within the interconnect at different contact resistances.
[0025] Figure 8 Vacancy concentration distribution within the interconnect at different contact resistances.
[0026] Figure 9 is the vacancy diffusion flux within the interconnect at different contact resistances.
[0027] Figure 10 is the failure time of interconnection under different contact resistances. DETAILED DESCRIPTION
[0028] The present invention is described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, without departing from the scope of the present invention, a number of variations and improvements may be made by those skilled in the art. These all fall within the scope of protection of the present invention.
[0029] In the following example, a typical hybrid bonding interconnection structure is selected to describe in detail a method for analyzing the reliability and failure mechanism of hybrid bonding interconnections of advanced heterogeneous heterogeneous integration proposed in the present invention. However, the method for analyzing the reliability and failure mechanism of hybrid bonding interconnections of advanced heterogeneous heterogeneous integration proposed in the present invention is not only applicable to this example, but also applicable to interconnections that require bonding processes to manufacture.
[0030] Schematic diagram of the three-dimensional structure of hybrid bonding interconnection Figure 3 As shown in (a). The xz cross section of the hybrid bonding interconnect is shown in Figure 3 As shown in (b). The thermal equivalent layer is used to simulate the actual heat conduction environment. The boundary conditions are as follows Figure 3 As shown in (c). For the heat conduction equation, the top and bottom surfaces are set to 300K, and the side surfaces of Si and SiO2 are set to periodic boundary conditions. For the solid mechanics equilibrium equation, the top and bottom surfaces are fixed, while the side surfaces of Si and SiO2 are set to periodic boundary conditions. For the vacancy diffusion equation, the side surfaces of the hybrid bonded interconnect are set to zero flux boundary conditions. For the current continuity equation, the top surface of the copper pillar is set to ground, and the bottom surface of the copper pillar is set to 10mV.
[0031] against Figure 3 For the structure shown in the figure, during the numerical simulation, the contact resistance of the bonding interface is first calculated according to the process conditions and then inserted into the current continuity equation. Then, based on the numerical simulation method, equations (3)-(15) are coupled and solved to simulate the electromigration process within the interconnect.
[0032] 1. Bonding interface contact resistance simulation
[0033] The contact resistance at the interconnect bonding interface is calculated using the Mikic elastic relation,
[0034]
[0035] where R CER is the contact resistance, σ contact is the contact interface conductivity, Y Cu is the Young's modulus of the interconnect material, ν Cu is the Poisson's ratio of the interconnect material, m asp is the average slope of the contact interface roughness, r asp is the contact interface roughness, p c is the bonding pressure.
[0036] 2.Electromigration process simulation:
[0037] During electromigration, the vacancy diffusion equation can be written as,
[0038]
[0039] Where t is time, c v is the vacancy concentration, j v is the vacancy flux. G is the vacancy generation rate. v The expression is,
[0040]
[0041] Among them D v is the vacancy diffusion coefficient. k is the Boltzmann constant, T is the temperature, z is the vacancy effective charge, e is the unit charge. E is the electric field strength, f is the vacancy relaxation ratio, Ω is the atomic volume, σ h is the static horizontal pressure. Q a is the atomic transport heat source. h The expression is,
[0042]
[0043] where σ xx / σ yy / σ zz is the normal stress component. The expression of G is,
[0044]
[0045] Where τ is the vacancy relaxation time. C v0 is the initial vacancy concentration. The mechanical stress can be calculated using the solid mechanics equilibrium equation,
[0046]
[0047] Among them C e is the elastic coefficient matrix, ε e is the total strain, ε vol is the volume strain caused by vacancy movement, ε th is the thermal expansion strain, F vis the body force. vol The expression is,
[0048]
[0049] The expression for thermal expansion strain is,
[0050] ε th =α e (TT ref ) (9)
[0051] where α e is the coefficient of thermal expansion, T ref is the initial temperature.
[0052] Calculate the temperature distribution based on the heat conduction equation,
[0053]
[0054] where k e is the thermal conductivity. Q h Is the heat source. In interconnect bonding, the heat source can be calculated by Joule's law,
[0055] Q h =J·E (11) where J is the current density. The electric field E and current density J can be calculated using the current continuity equation,
[0056]
[0057] J=σ e E+J e (13)
[0058]
[0059] where σ e is the conductivity, J e is the external current density, Q j,v is the current source and V is the potential.
[0060] 3. Vacancy nucleation simulation
[0061] Calculate the volume V of the void caused by vacancy diffusion using the vacancy flux void ,
[0062] V void =j v ·dt·δ·Ω (15)
[0063] where dt is the time step and δ is the surface area of the FEM element.
[0064] Figure 4(a1) to (a6) show the xz cross-sectional morphologies of hybrid bonded interconnects after failure at different contact resistances to illustrate the importance of contact resistance, where the failure criterion is set to a 20% increase in interconnect resistance. Figure 4 The black holes in (a1) to (a6) represent the voids caused by electromigration. Figure 4 As shown in (a1) to (a3), when the contact resistance is less than 2.7mΩ·μm 2 When , the void nucleation mainly occurs in the green circle. Figure 4 As shown in (a4) to (a6), when the contact resistance is greater than 2.7mΩ·μm 2 As the contact resistance increases, the position of the void nucleation moves from the top of the copper pillar to the bonding interface.
[0065] Figure 5 (a) and (b) show the case without considering the contact resistance and the case with the contact resistance of 50mΩ·μm respectively. 2 Initial potential distribution in the interconnect xz cross section. Figure 5 (c) shows the potential distribution of the interconnect center along the z direction. The electric field at the bonding interface under different contact resistances is shown in Figure 2. Figure 5 As shown in (d), the electric field at the bonding interface increases with the increase of contact resistance.
[0066] Figure 6 (a) and (b) show the case without considering the contact resistance and the case with the contact resistance of 50mΩ·μm respectively. 2 Initial temperature distribution in the interconnect xz cross section. Figure 6 (c) shows the temperature distribution of the interconnect center along the z direction. The maximum temperature and input power under different contact resistances are shown in Figure 2. Figure 6 As shown in (d), since the input power of the interconnect decreases with increasing contact resistance at a fixed input voltage, the maximum temperature decreases with increasing contact resistance.
[0067] Figure 7 (a) and (b) show the case without considering the contact resistance and the case with the contact resistance of 50mΩ·μm respectively. 2 Normalized vacancy concentration distribution in the interconnect xz cross section of (t = 10 h). Figure 7 (c) shows the normalized vacancy concentration distribution along the z direction of the interconnection center at t = 10h. The gradient of the normalized vacancy concentration along the z direction of the bonding interface under different contact resistances is shown in Figure 2. Figure 7 As shown in (d), the gradient of the normalized vacancy concentration in the z direction at the bonding interface increases with the increase of contact resistance, because the increase of the electric field on the bonding interface provides a greater driving force for the vacancy diffusion at the bonding interface.
[0068] Figure 8(a) and (b) show the case without considering the contact resistance and the case with the contact resistance of 50mΩ·μm respectively. 2 The hydrostatic stress distribution in the xz cross section of the interconnection (t = 10h). The hydrostatic stress distribution along the z direction of the interconnection center at t = 10h is as follows Figure 8 As shown in (c). The hydrostatic stress gradient in the z direction of the bonding interface under different contact resistances is shown in Figure 8 As shown in (d), the hydrostatic stress gradient in the z direction at the bonding interface increases with the increase of contact resistance due to the increase in vacancy concentration at the cathode, which leads to the increase of hydrostatic stress at the cathode.
[0069] Figure 9 (a) and (b) show the case without considering the contact resistance and the case with the contact resistance of 50mΩ·μm respectively. 2 Vacancy flux distribution in the z direction of the xz section (t=10h). Figure 9 (c) shows the change of the vacancy diffusion flux in the center of the interconnection in the z direction at t = 10h. The vacancy diffusion flux at the bonding interface under different contact resistances is shown in Figure 2. Figure 9 When the contact resistance is not considered, the maximum diffusion flux is located at Figure 9 In (a), near the top corner of the interconnect, the current path suddenly changes at the corner, resulting in an increase in local current density. However, when the contact resistance = 50mΩ·μm 2 When , the maximum vacancy diffusion flux is at the bonding interface, and the vacancy diffusion flux at the bonding interface increases with the increase of contact resistance, as shown in Figure 9 As shown in (d), this is due to the increase of electric field, vacancy concentration gradient and hydrostatic stress gradient. Figure 10 As shown in Figure 1, the inset shows the change in interconnect resistance over time under different contact resistances, where the standard setting is a 20% increase in interconnect resistance. As the contact resistance increases, the life of the interconnect shortens because the increase in contact resistance enhances the vacancy diffusion flux and accelerates vacancy migration.
[0070] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.
Claims
1. A method for analyzing reliability and failure mechanism of hybrid bonding interconnects in advanced heterogeneous heterogeneous integration, characterized in that: The steps include: 1) Calculate the contact resistance of the bonding interface based on the advanced heterogeneous heterogeneous integrated hybrid bonding process conditions; 2) Using the bond interface contact resistance as the input for electromigration simulation, a numerical method is then used to simulate the multi-physics process of vacancy evolution induced by electromigration within the interconnect. 3) Analyze interconnection reliability and failure mechanism based on simulation results.
2. The method for analyzing reliability and failure mechanism of advanced heterogeneous heterogeneous integrated hybrid bonding interconnects according to claim 1, characterized in that: The process conditions described in step 1) include bonding pressure, material type, and surface roughness of the bonding interface.
3. The method for analyzing reliability and failure mechanism of advanced heterogeneous heterogeneous integrated hybrid bonding interconnects according to claim 1, characterized in that: In step 1), the contact resistance at the interconnect bonding interface is calculated using the Mikic elastic relationship.
4. The method for analyzing reliability and failure mechanism of advanced heterogeneous heterogeneous integrated hybrid bonding interconnects according to claim 1, characterized in that: The electromigration simulation described in step 2) includes coupled solution of the current continuity equation, the heat conduction equation, the solid mechanics equilibrium equation, and the vacancy diffusion equation, and the bonding interface contact resistance is considered when solving the current continuity equation.
5. The method for analyzing reliability and failure mechanism of advanced heterogeneous heterogeneous integrated hybrid bonding interconnects according to claim 1, wherein: The analysis of interconnect reliability and failure mechanism described in step 3) includes at least one of the following: (a) analyzing the change of interconnect resistance over time under different bonding interface contact resistances; (b) analyzing the current distribution within the interconnect under different bonding interface contact resistances; (c) analyzing the temperature distribution within the interconnect under different bonding interface contact resistances; (d) analyzing the stress distribution within the interconnect under different bonding interface contact resistances; (e) analyzing the vacancy concentration and vacancy diffusion flux within the interconnect under different bonding interface contact resistances; (f) analyzing the vacancy nucleation position within the interconnect under different bonding interface contact resistances.