Composite circuit substrate structure

A composite circuit substrate structure includes a first dielectric layer, a second dielectric layer, a glass fiber structure, and a patterned circuit. The first dielectric layer has a first surface and a second surface opposite to each other. The second dielectric layer is disposed on the first dielectric layer and entirely connected to the first surface. The glass fiber structure is distributed in the second dielectric layer. The patterned circuit is embedded in the first dielectric layer from the second surface, and the patterned circuit is not contacted with the glass fiber structure.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan application serial no. 98105421, filed on Feb. 20, 2009. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of specification.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present application relates to a circuit substrate structure, and more particularly to a composite circuit substrate structure.

2. Description of Related Art

In current semiconductor package technology, a circuit substrate is one of the most frequently used components. The circuit substrate is mainly formed by stacking a patterned circuit and a dielectric layer. The dielectric layer is commonly made of resin. Since structural strength of resin is relatively weak, a glass fiber structure can be distributed in the dielectric layer, so as to increase the structural strength of the dielectric layer.

In a circuit substrate having an embedded patterned circuit, when glass fiber is distributed in a dielectric layer, a patterned circuit is likely to contact the glass fiber structure in the dielectric layer. During an electroplating process, an electroplating solution possibly permeates into a gap between the glass fiber structure and the dielectric layer, and conductive metal is then formed in the gap after the electroplating process is performed. What is described above is called permeating. Two conductive wires in the patterned circuit may be connected through the conductive metal, thus giving rise to short circuit.

In addition, when a voltage is applied or moisture is increased in a reliability test, metal particles in the two conductive wires having a relatively small pitch therebetween move to the gap between the glass fiber structure and the dielectric layer due to electron mobility. Nonetheless, the metal particles accumulated in the gap cause short circuit in the two conductive wires having the relatively small pitch.

SUMMARY OF THE INVENTION

The present application is directed to a composite circuit substrate structure with lower probability of causing short circuit in the patterned circuit of the composite circuit substrate structure by permeating or electron mobility.

A composite circuit substrate structure of the present application includes a first dielectric layer, a second dielectric layer, a glass fiber structure, and a patterned circuit. The first dielectric layer has a first surface and a second surface opposite to each other. The second dielectric layer is disposed on the first dielectric layer and entirely connected to the first surface. The glass fiber structure is distributed in the second dielectric layer. The patterned circuit is embedded in the first dielectric layer from the second surface, and the patterned circuit is not contacted with the glass fiber structure.

According to an embodiment of the present invention, a material of the first dielectric layer is resin.

According to an embodiment of the present invention, a material of the second dielectric layer is resin.

According to an embodiment of the present invention, the glass fiber structure is glass fiber cloth.

According to an embodiment of the present invention, the first dielectric layer has a patterned concave located on the second surface.

According to an embodiment of the present invention, the patterned circuit is accommodated in the patterned concave.

According to an embodiment of the present invention, a depth of the patterned concave is greater than a thickness of the patterned circuit.

According to an embodiment of the present invention, the second dielectric layer is laminated onto the first dielectric layer.

According to an embodiment of the present invention, the first dielectric layer includes a plurality of catalyst particles.

Based on the above, the patterned circuit in the composite circuit substrate structure of the application does not contact with the glass fiber structure in the dielectric layer, so as to reduce the probability of causing short circuit by permeating or electron mobility.

In order to make the aforementioned and other features and advantages of the present invention more comprehensible, several embodiments accompanied with figures are described in detail below.

DESCRIPTION OF EMBODIMENTS

FIG. 1is a cross-section view of a composite circuit substrate structure according to an embodiment of the present invention. Referring toFIG. 1, the composite circuit substrate structure100of the present embodiment includes a first dielectric layer110, a second dielectric layer120, a glass fiber structure130, and a patterned circuit140.

The first dielectric layer110has a first surface112and a second surface114opposite to each other. The second dielectric layer120is disposed on the first dielectric layer110and entirely connected to the first surface112. The glass fiber structure130is distributed in the second dielectric layer120. The patterned circuit140is embedded in the first dielectric layer110from the second surface114, and the patterned circuit140is not contacted with the glass fiber structure130. When conductive metal is formed in a gap between the second dielectric layer120and the glass fiber structure130due to permeating or electron mobility, short circuit of the patterned circuit140caused by contacting the conductive metal can be prevented.

As shown inFIG. 1, in the present embodiment, the first dielectric layer110has a patterned concave114alocated on the second surface114, and the patterned circuit140is deposited in the patterned concave114a.

To better elaborate the composite circuit substrate structure100of the present embodiment, a manufacturing process of the composite circuit substrate structure100of the present embodiment is described hereafter with reference toFIGS. 2A to 2D.

FIGS. 2A to 2Dare flowcharts illustrating fabrication of the composite circuit substrate structure depicted inFIG. 1. As shown inFIG. 2A, a second dielectric layer120is provided at first. Here, a glass fiber structure130is distributed in the second dielectric layer120. Next, the second dielectric layer120is laminated onto a first surface112of a first dielectric layer110. In the present embodiment, the first dielectric layer110and the second dielectric layer120are made of resin, for example. The glass fiber structure130is, for example, glass fiber cloth.

A method of distributing the glass fiber structure130in the second dielectric layer120includes dipping glass fiber cloth in liquid resin and taking out the dipped glass fiber cloth from the resin. Resin is adhered to the glass fiber cloth taken out of the resin. After the resin is cured, a dielectric layer in which the glass fiber is distributed can be obtained.

Referring toFIG. 2B, a patterned concave114ais formed on a second surface114of the first dielectric layer110by laser ablation. Next, as indicated inFIG. 2C, an electroplating seed layer150is formed on the second surface114and the patterned concave114aby chemical electroplating, which is conducive to implementation of a subsequent electroplating process. Thereafter, referring toFIG. 2D, a metal layer160is formed on the electroplating seed layer150by performing an electroplating process, and a portion of the metal layer160is removed by etching, so as to form the composite circuit substrate structure100illustrated inFIG. 1.

Referring toFIGS. 1 and 2D, the etching process is performed to remove the portion of the metal layer160on the second surface114, so as to obtain the patterned circuit140. However, a portion of the metal layer160located in the patterned concave114aand adjacent to the second surface114is also likely to be removed during implementation of the etching process. Therefore, a depth D1of the patterned concave114ais greater than a thickness D2of the patterned circuit140.

Note that the patterned concave114ais disposed in the first dielectric layer110without being extended to the second dielectric layer120, and thus the patterned circuit140located in the patterned concave114adoes not contact with the glass fiber structure130.

According to another embodiment that is not shown in the drawings, the first dielectric layer110can have a plurality of catalyst particles distributed therein. During formation of the patterned concave114aby using laser, the catalyst particles located on a surface of the patterned concave114aare activated. Hence, in comparison with the above embodiment, the embodiment not shown in the drawings teaches formation of the patterned circuit140in the patterned concave114aby chemical electroplating in no need of forming the electroplating seed layer150on the second surface114and the patterned concave114a.

Moreover, in still another embodiment that is not shown in the drawings, resin coated copper (RCC) can be employed to replace the first dielectric layer110depicted inFIG. 2A, and then the composite circuit substrate structure illustrated inFIG. 1can be formed by applying a manufacturing method similar to the above. The RCC includes a dielectric layer and a metal layer disposed thereon. The metal layer is, for example, copper foil, such that the dielectric layer can be equipped with a relatively leveled surface.

In light of the foregoing, the patterned circuit in the composite circuit substrate structure of the application does not contact with the glass fiber structure in the dielectric layer. When the conductive metal is formed in the gap between the dielectric layer and the glass fiber structure due to permeating or electron mobility, short circuit of the patterned circuit caused by contacting the conductive metal can be better prevented.