[Retracted] Fabrication of Hollow Needle Tips with Nanoholes by Plasma Maskless Processing and Calculation and Detection of Complex Surface Edges

Table 3

The imidization parameters of polyamic acid.

	PI-2611	ZKPI-305	ZKPI-800	Ni
Dielectric constant (1 MHz, 0–50%Rh)	2.9	3.2–3.4	3.0–3.4	0
Dielectric breakdown strength (V/µm)	200	250–350	200–350	0
Thermal expansion coefficient (ppm)	3	30–35	3–4	13
Internal stress(10 µm) (MPa)	2	30–35	0	0
Elongation at break (%)	100	10–20	20–30	0
Glass transition temperature	360	260–280	360	0