Effect and Mechanism of the Surface Treatment and Gradation Filling of AlN on the Performance of Insulation Layer of Copper Clad Laminate

doi:10.15541/jim20200639

Abstract

Abstract:

Introducing thermally conductive ceramic fillers to the copper clad laminate (CCL) resin matrix is an effective way to improve its thermal conductivity. AlN is a kind of ceramic filler with high thermal conductivity and good insulation, but its easy hydrolysis has limited its practical application. In addition, compared with the ceramic filler-resin matrix composite system, systematic research on the properties of the filler filled CCL is relatively rare. In this study, AlN was treated with phosphoric acid to obtain pAlN with excellent hydrolysis resistance. Then, the effects of different pAlN particle sizes and filling amount on the thermal conductivity, peeling strength, dielectric properties and other properties of AlN-filled CCLs were investigated. Finally, the pAlN gradation filling strategy of different particle sizes was adopted to explore the influence of different gradation schemes on the performance of the CCLs, of which the CCL with the best gradation and excellent comprehensive performance was obtained. The results show that the thermal conductivity of CCL insulating layer increases to 0.757 W/(m·K), 160% higher than that of pure resin CCL under the optimal gradation of pAlN-50 μm60%-5 μm5%. It displays excellent mechanical properties ( peel strength of 1.012 N/mm and bending strength of 335 MPa), dielectric properties (dielectric constant of 4.499 and dielectric loss of 6.668×10^-3), and the water absorption which is as low as 0.53%. All these data could be a promising guidence for CCL application.

Key words: AlN, thermal conductive filler, hydrolysis resistance, gradation filling, copper clad laminate

CLC Number:

TB332

ZHANG Weiwei, LU Chen, YING Guobing, ZHANG Jianfeng, JIANG Wan. Effect and Mechanism of the Surface Treatment and Gradation Filling of AlN on the Performance of Insulation Layer of Copper Clad Laminate[J]. Journal of Inorganic Materials, 2021, 36(8): 847-855.

Figures/Tables 12

Fig. 1 Schematic diagrams of (a) the anti-hydrolysis mechanism of phosphoric acid on AlN and (b) the preparation process of CCL

Fig. 2 (a-d) Particle size distribution curves and (e-h) SEM images of AlN with different particle sizes (a) 1 μm AlN; (b) 5 μm AlN; (c) 50 μm AlN; (d) 80 μm AlN; (e-h) SEM images of the AlN corresponding to (a-d)

Fig. 3 XRD patterns of samples before and after hydrolysis (a) AlN; (b) AlN after treatment with phosphoric acid (pAlN)

Fig. 4 SEM images of (a-d) cross-sections and (e-h) surfaces of CCLs filled with pAlN of same filling ratio but different sizes (a) pAlN-1 μm; (b) pAlN-5 μm; (c) pAlN-50 μm; (d) pAlN-80 μm; (e-h) SEM images corresponding to the surfaces of (a-d) CCLs

Fig. 5 SEM images of the cross-section of CCLs with different filling ratios of pAlN((a) no filler; (b) pAlN-50 μm-20%; (c) pAlN-50 μm-60%; (d) pAlN-50 μm60%-5 μm5%); (e) EDS scan selection area with the inset showing the element distribution; (f) the full element scan image; (g-j) corresponding element distributions of Al, N, Si, C

Fig. 6 Heat conduction mechanism diagram of CCLs under different filling schemes (a) Without filler; (b) With single-size filler; (c) With graded filler

Fig. 7 (a) Effects of pAlN with different sizes, different filling amounts and (b) gradation filling (pAlN-50 μm x%-5 μm y%, x=0-60, y=0-15, same below) on the thermal conductivity of CCLs

Table 1 Effect of phosphoric acid treatment of AlN on the performance of CCLs

Treatment	Thermal conductivity/ (W·m^-1·K^-1)	Peel strength/ (N·mm^-1)	Dielectric constant	Dielectric loss/×10^-3	Bending strength/MPa	Water absorption/%
Without fillers	0.291	0.949	3.90	5.41	220	0.40
AlN-1 μm60%	0.390	0.380	5.10	9.10	208	0.76
pAlN-1 μm60%	0.610	0.980	4.55	9.04	282	0.47

Fig. 8 (a) Effects of pAlN with different sizes, different filling amounts and (b) gradation filling on the peel strength of CCLs

Fig. 9 (a) Effects of pAlN with different sizes, different filling amounts and (b) gradation filling on the bending strength of CCLs

Fig. 10 Effect of pAlN with different size and filling amount on the dielectric constant (a) and dielectric loss (b) of the CCLs; Influence of gradation filling on the dielectric constant (c) and dielectric loss (d) of corresponding CCLs

Fig. 11 (a) Effect of pAlN with different size and different filling amount and (b) gradation filling on the water absorption of CCLs

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