High-speed filling method for copper

Inactive Publication Date: 2017-02-16
JCU CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The invention provides a method for faster copper plating to fill holes and grooves in a substrate. Compared to usual methods, this method uses an acidic copper plating solution with a high solubility of copper oxide, ensuring sufficient copper source replenishment and continuous filling. Its higher bath temperature also allows for better dispersion of copper ions and further improves the speed of coating.

Problems solved by technology

In general, for increasing the rate of copper plating, it is considered to increase the temperature and the copper ion concentration, and to increase the current density, but in the case where these factors are increased on filling holes or grooves by copper plating, it has been known that the leveling function and the filling capability may be lowered, the appearance of plating may be deteriorated, the properties of the plated film may be deteriorated, and the like.
In the case where copper plating is performed with a phosphorus-containing copper anode, the black film is eluted on increasing the temperature, and copper ion as monovalent copper is eluted into the bath from the black film or the surface of the anode that is not covered with the black film, and alters the additives, thereby deteriorating the capabilities including the leveling property, the uniform electrodeposition property, the filling property, and the like.
For suppressing the alteration of the additives, it is necessary to retain a high dissolved oxygen concentration in the bath, but it has been considered that the saturation solubility of dissolved oxygen is decreased on increasing the temperature of the bath, which results in a vicious cycle.
In the filling plating, on the other hand, holes can be aligned with each other on laminating the substrates since the holes can be filled with copper, thereby decreasing the size and the area of the substrate, but the aforementioned technique cannot be applied to the filling plating.

Method used

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  • High-speed filling method for copper
  • High-speed filling method for copper
  • High-speed filling method for copper

Examples

Experimental program
Comparison scheme
Effect test

example 1

Filling of Via

[0048]A printed circuit board having a substrate copper foil having formed therein plural vias each having an opening diameter of 120 μm and a depth of 70 μm was subjected to electroless copper plating according to an ordinary method, so as to provide a test substrate. Separately, an acidic copper plating solution containing the components shown in Table 1 was prepared by mixing and dissolving the components in pure water. The vias of the test substrate were filled by copper plating by using the acidic copper plating solution under the condition shown in Table 2. The copper plating was performed under air agitation of the acidic copper plating solution. The copper plating was terminated at the time when the thickness of the surface layer copper plating reached 20 μm.

[0049]The copper plating was performed by the following process steps in this order.[0050]Acidic degreasing (PB-242D, produced by JCU Corporation): 45° C., 3 minutes[0051]Water rinsing: 1 minute[0052]Acid a...

example 2

Evaluation of Property of Film

[0073]A smooth stainless steel plate was degreased with a degreasing agent (SK-144, produced by JCU Corporation), lightly rubbed with polyurethane sponge (Scotch Brite, produced by 3M Company), then rinsed with water, acid-activated with a 10% sulfuric acid solution, and subjected to copper plating under the condition shown in Table 3, so as to provide a copper plated film having a thickness of approximately 50 μm. The resulting copper plated film was peeled off from the base, and subjected to a heat treatment at 120° C. for 1 hour.

[0074]The copper plated films thus obtained above each were punched out into a test specimen having a dumbbell shape with the size shown in FIG. 4, measured for the thickness of the plated film with a digital micrometer, and then subjected to a tensile test and a hardness measurement test under the following conditions, whereby the elongation and the tensile strength (tensile test) and the hardness of the plated film (hardnes...

example 3

Filling of Through Hole

[0085]A printed circuit board having a substrate copper foil having formed therein plural through holes each having an opening diameter of 100 μm and a thickness (including the copper foil) of 120 μm was subjected to electroless copper plating according to an ordinary method, so as to provide a test substrate. Separately, an acidic copper plating solution containing the components shown in Table 4 was prepared by mixing and dissolving the components in pure water. The through holes of the test substrate were filled by copper plating by using the acidic copper plating solution under the condition shown in Table 5. The copper plating was performed under jet agitation of the acidic copper plating solution. The copper plating was terminated at the time when the thickness of the surface layer copper plating reached 20 μm.

[0086]The copper plating was performed by the following process steps in this order.[0087]Acidic degreasing (PB-242D, produced by JCU Corporation)...

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Abstract

To provide a technique of increasing a rate of filling holes or grooves formed in a substrate, by changing the temperature, the concentration, the current density, and the other conditions of the ordinary copper plating. A method for filling holes or grooves formed in a substrate by copper plating at a high speed, containing: immersing the substrate having the holes or grooves in an acidic copper plating solution containing a copper ion, a sulfate ion, and a halide ion, at from 30 to 70° C.; and plating the substrate at a current density of 3 A / dm2 or more by using an insoluble electrode as an anode.

Description

TECHNICAL FIELD[0001]The present invention relates to a method for filling holes, such as a via and a through hole, or grooves, such as a trench, formed in a substrate, by copper plating at a higher speed than the ordinary technique.BACKGROUND ART[0002]The substrate structure of a portable phone, which is a representative example of compact electronic equipments, is having an increased density, and a buildup technique is essential for producing the substrate. In the buildup technique, there is an increasing importance of a technique for filling holes, such as a via and a through hole, or grooves, such as a trench, formed in a substrate having multiple layers laminated, by copper plating. Furthermore, a technique of filling a through-silicon via (which is one kind of vias) by copper plating receives attention as one of three-dimensional packaging techniques in the field of semiconductor.[0003]The filling of holes or grooves formed in a substrate, for example a via having an opening d...

Claims

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Application Information

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IPC IPC(8): C25D7/12C25D5/02C25D5/34C25D3/38
CPCC25D7/12C25D5/34C25D5/02C25D3/38C25D5/08C25D5/627C25D21/12H01L21/76879
InventorOMORI, TAKAFUMIYASUDA, KIROKIANDO, SYUNSUKE
OwnerJCU CORP