Chemical copper plating liquid applied to zinc oxidepressure sensitive resistor copper electrode and copper plating technique thereof

Abstract

The invention belongs to the field of electronic devices and particularly relates to chemical copper plating liquid applied to a zinc oxide pressure sensitive resistor copper electrode and a copper plating technique thereof. The chemical copper plating liquid comprises copper sulfate, EDTA and / or EDTA disodium, tetrahydroxypropyl ethylenediamine, disodium edetate dihydrate, sodium hydroxide, sodium monophosphate, hydrazine hydrate, 2,2'-bipyridyl, a surface active agent, an accelerator and an antioxidant. A material obtained through a preparation method and used for preparing a zinc oxide pressure sensitive resistor is excellent in performance, the chemical copper plating liquid does not contain a toxic substance, namely formaldehyde, the production process is environmentally friendly, theuniformity, corrosion resistance, hardness and weldability of a prepared plated layer are excellent, and combination of the plated layer and zinc oxide is firm.

Description

technical field [0001] The invention belongs to the field of electronic devices, and in particular relates to an electroless copper plating liquid applied to copper electrodes of zinc oxide piezoresistors and a copper plating process thereof. Background technique [0002] The varistor is a voltage limiting type of protection period. Utilizing the nonlinear characteristics of the varistor, when an overvoltage occurs between the two poles of the varistor, the varistor can clamp the voltage to a relatively fixed voltage value, never realizing the protection of the subsequent circuit. In recent years, with the rapid development of information technology, the miniaturization, multi-function, and high stability of electronic equipment are called the inevitable trend of development, and the varistor as a protective semiconductor element is also correspondingly moving toward thinner, lower voltage, and higher Reliability is developing, and zinc oxide varistors have been widely used...

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Problems solved by technology

But the reducing agent that the electroless copper plating liquid of this invention adopts is formaldehyde, does not satisfy the requirement of energy saving and environmental protection

[0005] The invention patent with application number 201110348879.5 discloses an electroless copper plating solution on the surface of zinc alloy and its copper plating process. The electroless copper plating solution includes: copper sulfate pentahydrate 5-7g / L, complexing agent 30-70g / L , sodium hydroxide 90-120g / L, sodium hypophosphite 4-10g / L, 2,2'-bipyridine 90-110mg / L, potassium ferrocyanide 10-20mg / L, is a formaldehyde-free , acetaldehyde, etc. have major hazards to the environment and the human body. Although the invention avoids the use of formaldehyde, the electroless copper plating solution has poor stability, and the coating is insufficient in uniformity, corrosion resistance, hardness, and weldability.

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