The invalidation of via-hole connect is one of the major issues in TFT-LCD industry. To solve out this issue

the influence of different via-hole etch mode (ICP and ECCP) was analyzed; the effects of ECCP mode etching parameters (chamber pressure

bias/source RF power and O

2

/SF

6

gas ratio) on the etching rate and homogeneity were investigated by the four factor method

and the optimum etching parameters of the ECCP over hole improvement were obtained. The results show that the physical bombardment in the etching process of silicon nitride under the ECCP mode is the main factor to induce the corrosion of the pores in the lower edge of the GI section and the contact area of the Cu

which doesn't happen under ICP mode. The etch rate increases with the increasing of chamber pressure

and the uniformity decreases. The rate increases with the in creasing of source and bias power

the uniformity increases with source power and decreases with bias power. The impact of ratio gas (O

2

/SF

6

) on etching rate is very small

and the higher the O

2

content

the better the homogeneity. In order to achieve the purpose of protecting the lower section of GI with photoresist (PR)

the reaction pressure is increased to 1.7 Pa

the bias RF power is reduced by 30 kW

the source RF power is increased by 30 kW and the O

2

/SF

6

gas is kept to 1:1

which increase the etching amount of silicon nitride

and the internal shrinkage of the PR glue is reduced

which avoid the surface damage of the sputtering. Under this etching parameters

the etching rate is 750 nm/s

the uniformity is 10%

and the corrosion rate is from 10% to 0. The corrosion of the via-hole under ECCP etching mode is solved effectively.