A kind of reducing electroless gold plating liquid and its preparation method and use method and application

Abstract

The invention provides a reduction type chemical gold plating solution and a preparation method, an application method and applications thereof. The reduction type chemical gold plating solution comprises following components: gold ions (2-5 g / L), a main reducing agent (1-10 g / L), an auxiliary reducing agent (0.5-2 g / L), a main complexing agent (3-40 g / L), and an auxiliary complexing agent (1-20 g / L). The provided reduction type chemical gold plating solution can reach a plating speed of 1 [mu]m / h; finally the morphology of an obtained gold plated layer is compact, skip plating is avoided, thethickness of the gold plated layer is 0.05-3 [mu]m; the bonding force between the gold plated layer and a basic material is good, the application requirements can be met; and the provided reduction type chemical gold plating solution can be applied to an ENAG technology, an EPAG technology, and an ENEPAG technology.

Description

technical field [0001] The invention belongs to the technical field of cyanide-free electroless plating, and relates to a reduced electroless gold plating solution, a preparation method, a use method and an application thereof. Background technique [0002] Gold-plated surface treatment technology has good decoration, solderability, corrosion and wear resistance, oxidation resistance and other properties, and is widely used in hardware, decoration, FPC, PCB, IC and wafer-level packaging and other fields. There are two main methods of obtaining gold plating: electroplating and electroless plating. With the miniaturization of electronic components, the development of high-density interconnection technology and the thinning and thinning of semiconductor packaging, the demand for electroless gold plating technology is increasing. [0003] The early electroless gold plating technology used cyanide as the main complexing agent, and potassium borohydride and dimethylamine borane a...

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Problems solved by technology

[0003] The early electroless gold plating technology used cyanide as the main complexing agent, and potassium borohydride and dimethylamine borane as the reducing agent, but cyanide is a highly toxic substance, which has serious safety problems, and cyanide is widely used in semiconductor manufacturing. Photoresist stripping is very easy to occur; in addition, this type of plating solution has poor shielding properties for impurity ions and impurity organic matter, the plating solution lacks stability, gold plating is easily affected, and the gold plating rate is slow, etc.

Therefore, cyanide-free gold plating has attracted more and more attention, but compared with cyanide gold plating, cyanide-free gold plating has problems such as easy degradation of the plating solution and poor quality of the coating.

[0004] CN105543816A discloses an electroless gold plating solution, wherein sulfite and thiosulfate are used as compound complexing agent, and thiourea is used as reducing agent, although the stability of the plating solution is good, but the thiourea itself is oxidized The product is insoluble in water, which will cause missing plating of the coating and affect the solderability of the gold layer; CN104736739A discloses a cyanide-free gold plating bath and a preparation method thereof, wherein ascorbic acid is used as a The reducing agent effectively avoids the shortcoming of thiourea, but the reduction efficiency of ascorbic acid is very low, and in order to reach the practical plating speed, it often needs to be added in excess, which affects the stability of the bath; CN104520471A discloses a plating bath composition for immersion plating of gold, Among them, the cyanide-free chemical gold plating system uses sulfite and thiosulfate as the complexing agent and hydroxyalkylsulfonic acid as the reducing agent. The chemical gold plating is to plate a layer of nickel with a thickness of about 7 μm on the copper foil. On the nickel layer, nickel is used as a catalyst and self-catalyzed electroless gold plating (ENAG process) by gold. Although this method can obtain a more stable gold plating layer, the surface treatment process that can be applied is relatively single, and cannot be used for chemical nickel palladium- Reduced gold process (ENEPAG process) and chemical palladium-reduced gold process (EPAG process)

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