Table 4.

Effect of trace element addition on the microstructure of In-based/Sn-Bi/Sn-Zn solder.

Solder	Element	wt. %	Reflow/°C	Aging/h	thermal cycles/t	Grain Size	Bi-rich phase	Zn-rich phase	reliability	Referen-ce
In	Bi	22	85–200			↓				[50]
	Sn	48	160			↓↓			√√	[51]
Sn-Bi	P	1				↓			√	[54]
	Cu	1			2000	↑				[55,56]
	In	2.5				↓	↓			[57,63]
	Zn	1					↓			[58]
	Ni	1		150		↓				[59]
	Al	2.3				↓				[60]
	Sb	1.5				↓			√	[62]
	Cr	0.2				↓↓				[64]
	CuZnAl	0.5				↓				[66,67]
	La	0.5		1000		↓↓			√√	[68]
	Ce	0.5				↓				[69]
	Ag, Re	1, trace					↓			[71]
	Ag nanoparticles	0.4					↓		√	[72]
	Cu6Sn5 nanoparticles	trace					↓		√	[73]
	CNTs	0.03				↓↓				[74,75]
	GNSs	0.04					↓↓			[76]
	Ti nanoparticles	0.1				↓			√	[114]
Sn-Zn	Ag	1.5						↓		[77]
	Bi	3	220					↓		[78]
	Cu	1.5						↓		[79]
	Al	0.09						↓		[80]
	Bi, Cr	3, 0.5						↓↓	√√	[80,82]
	Bi, Ag	3, 0.5						↓		[84]
	Sb	0.1						↓		[86,87]
	Ti	0.05						↓		[89]
	Ce (La)	0.5						↓		[90]
	Bi, Pr	3, trace						↓		[92]
	ZrO2 nanoparticles	trace					↓		√	[93]
	Al2O3 nanoparticles	trace					↓			[94]
	nano Ni	trace					↓			[95]

Notes:↓ = slightly decreased

↓↓ = remarkably decreased

↑ = slightly increased

↑↑ = remarkably increased

√ = slightly improved

√√ = remarkably improved