电子互连导电胶的力学性能及胶连点跌落冲击行为

熊蘅; 马宇宏; 司博文; 肖革胜; 树学峰

doi:10.11858/gywlxb.20210902

电子互连导电胶的力学性能及胶连点跌落冲击行为

doi: 10.11858/gywlxb.20210902

太原理工大学机械与运载工程学院应用力学研究所, 山西太原　030024

基金项目: 国家自然科学基金（11802198）；中国博士后科学基金（2021M702605）

详细信息

作者简介:
熊　蘅（1991－）, 男, 硕士研究生, 主要从事导电胶力学性能研究. E-mail：xh895111430@163.com

通讯作者:
肖革胜（1989－）, 男, 博士, 副教授, 主要从事电子互连材料力学行为及封装结构可靠性研究.E-mail：xiaogesheng@tyut.edu.cn

中图分类号: O347
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出版历程
- 收稿日期: 2021-11-15
- 修回日期: 2021-12-07
- 录用日期: 2022-01-18
- 刊出日期: 2022-05-30

Mechanical Properties of Electronic Interconnected Conductive Adhesive and Drop Impact Behavior of Adhesive Bonding Point

Institute of Applied Mechanics, College of Mechanical and Vehicle Engineering, Taiyuan University of Technology, Taiyuan 030024, Shanxi, China

摘要

摘要: 电子互连导电胶在便携式电子产品中具有广泛的应用前景，其在服役过程中常承受跌落冲击工况，导致微小导电胶互连点处产生相对较高的应变率，因此关于导电胶在较高应变率下的力学行为及胶连点跌落可靠性研究显得尤为重要。以环氧树脂基添加银导电颗粒各向同性导电胶（ICA）为研究对象，采用万能试验机和分离式霍普金森压杆装置对其开展不同应变率下的力学性能研究，在此基础上进行导电胶互连封装结构的跌落冲击数值模拟分析。结果表明：固化导电胶在动态时具有明显的应变率效应；跌落冲击时，关键胶连点出现在4个边角处且小角度跌落比水平跌落更危险；两种跌落方式中，基座长边跌落方式在关键胶连点处产生的应力、应变相对较大。
- 导电胶 /
- 力学性能 /
- 应变率 /
- 跌落冲击
Abstract: Electronic interconnected conductive adhesive has a wide range of application prospects in portable electronic products. It is often subjected to drop impact conditions during service, resulting in a relatively high strain rate at the bonding point of tiny conductive adhesive. Therefore, the research on the mechanical behavior of conductive adhesive under a higher strain rate and the drop reliability of bonding point is particularly important. Herein, the rate-dependent properties of the epoxy resin-based isotropic conductive adhesive (ICA) with silver conductive particles were investigated by using the universal testing machine and the split Hopkinson pressure bar. Furthermore, the numerical simulation analysis of the conductive adhesive interconnection package structure under drop impact was carried out. The dynamic results show that the cured ICA is sensitive to strain rate. It is clear that the key bonding point appears at the four corners, and the small-angle drop is more dangerous than that of the horizontal drop. The long-side drop mode results in a relatively large stress and strain at the key bonding point in comparison with that of the short-side drop mode.
- conductive adhesive /
- mechanical properties /
- strain rate /
- drop impact

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图 1 各向同性固化导电胶试样(a)及其SEM图像(b)

Figure 1. Test sample (a) and SEM image (b) of cured ICA

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图 2 各向同性固化导电胶的准静态(a)和动态(b)真应力-应变曲线

Figure 2. Quasi-static (a) and dynamic (b) true stress-strain curves of cured ICA

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图 3 导电胶互连封装结构自由跌落模型

Figure 3. Free drop model of ICA packaging structure

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图 4 同一角度两种跌落方式示意图

Figure 4. Schematic diagrams of two drop modes at the same angle

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图 5 各向同性固化导电胶的本构参数拟合结果

Figure 5. Constitutive parameters fitting curve of cured ICA

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图 6 PCB板的z向位移云图

Figure 6. z-axis displacement contour of PCB board

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图 7 不同跌落角度下的最大等效应力(a)和最大等效塑性应变(b)

Figure 7. The maximum Mises stress (a) and maximum PEEQ (b) at different drop angles

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图 8 不同跌落高度下的最大等效应力(a)和最大等效塑性应变(b)

Figure 8. The maximum Mises stress (a) and maximum PEEQ (b) at different drop heights

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表 1 不同应变率下固化导电胶的动态屈服强度

Table 1. Dynamic yield strength of cured ICA at different strain rates

Test No.	Strain rate/s⁻¹	Yield strength/MPa
1	1100	184.6
2	2100	215.8
3	3200	238.0

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表 2 基板和PCB板的横观各向同性参数

Table 2. Transversely isotropic parameters of substrate and PCB board

Component	E_x，E_y/GPa	E_z/GPa	G_xz，G_yz/GPa	G_xy/GPa	$\gamma$_xz，$\gamma$_yz	$\gamma$_xy	$\,\rho $/(kg·m⁻³)
Substrate	16.8	7.4	7.59	3.31	0.39	0.11	1910
PCB	17.7	7.8	7.99	3.49	0.39	0.11	1910

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表 3 各材料的力学参数

Table 3. Mechanical parameters of materials

Material	E/GPa	$\gamma$	$\,\rho $/(kg·m⁻³)
Bolt	206	0.28	7800
Chip	131	0.23	2330
Cu	117	0.38	8960
Resin	28	0.35	1890
Base	200	0.27	7800
Impact platform	20	0.20	2400

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表 4 ICA的力学参数

Table 4. Mechanical parameters of cured ICA

Material	E/GPa	$\gamma$	$\,\rho $/(kg·m⁻³)	C/s⁻¹	P
ICA	1.63	0.4	4050	3641	1.3

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表 5 不同跌落工况下的$\textit{z}$向最大应力

Table 5. Maximum $\textit{z}$-axis stress under different drop conditions

Height/m	$\sigma $₀/MPa	$\sigma $₁/MPa	$\sigma $₂/MPa	Height/m	Drop angle/(°)	$\sigma $₁₁/MPa	$\sigma $₁₂/MPa
1.0	150.1	148.2	−290.9	1.0	10	−193.6	−145.3
1.2	158.3	−175.2	−263.1	1.0	15	−155.9	−181.4
1.5	173.1	188.7	−270.0	1.0	20	92.5	−232.8
1.8	185.9	−194.4	−320.3	1.0	25	97.6	−146.0
2.0	193.5	196.2	−323.9	1.0	30	101.2	−132.4

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