A method of etching a soft dielectric substrate to form a circuit

Abstract

The invention discloses an etching method for a soft dielectric circuit, which comprises the steps: s1 providing a soft dielectric substrate, the surface of the soft dielectric substrate is covered with a copper conductor layer and a gold conductor layer sequentially from the inside to the outside, and the gold conductor layer form a resist pattern; s2 uses iodine-potassium iodide solution to etch the gold conductor layer until the interface between the gold conductor layer and the copper conductor layer is etched; s3 uses potassium iodide aqueous solution to soak the gold conductor layer and the copper conductor layer interface; s4 Use iodine-potassium iodide solution and potassium iodide aqueous solution to alternately treat the interface between the gold conductor layer and the copper conductor layer until the copper conductor layer on the surface of the unprotected area of ​​the resist on the soft dielectric substrate is completely exposed; s5 etches the copper conductor layer to remove the resist agent. The method of the present invention uses the potassium iodide aqueous solution to quickly and effectively dissolve the white insoluble precipitate generated when the iodine-potassium iodide solution corrodes the interface between the gold conductor layer and the copper conductor layer, and can process the copper-gold circuit and copper-gold on the soft dielectric substrate with high precision electrode layer.

Description

technical field [0001] The invention belongs to the technical field of microwave and millimeter wave integrated circuit manufacturing, and relates to a method for etching a soft dielectric substrate to form a circuit. Background technique [0002] Among the materials used in microwave and millimeter wave high-frequency circuits, soft dielectric polytetrafluoroethylene and its composite substrates have extremely low dielectric constant, small dielectric loss and low moisture absorption, making it suitable for ultra-high frequency applications. , ultra-wideband (2 to 10 octaves) microwave and millimeter wave circuits are widely used, which requires this kind of circuit to have a more perfect planar circuit pattern and highly reliable surface coating, not only to produce finer Line width / line spacing, flatter pads, and the final surface coating must meet assembly requirements such as gold wire bonding, soldering, and chip bonding. [0003] In view of the characteristics of man...

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Problems solved by technology

Scrubbing with absorbent cotton balls is also limited to solve the problem of deposit residue adhering to the copper layer, resulting in incomplete etching of the gold layer, and at the same time bringing serious difficulties to the subsequent etching of the copper layer. Etching time to achieve circuit pattern production

However, the prolongation of the wet etching time of the gold layer and the copper layer in the area protected by the resist mask increases the amount of side corrosion of the gold layer and the copper layer on the strip line in the area protected by the resist mask, and increases the number of defects on the circuit pattern. The quantity, it is impossible to obtain high-precision fine copper-gold circuit and copper-gold electrode layer on the soft dielectric PTFE substrate

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