TW201306681A - Ceramic circuit board and fabrication thereof - Google Patents

Abstract

The invention discloses a ceramic circuit board. The ceramic circuit board according to the invention includes a ceramic substrate and at least one lead. The ceramic substrate has an upper surface and at least one groove corresponding to the at least one lead and being formed on the upper surface. The at least one lead is formed by filing the at least one groove with a metal material.

Description

Ceramic circuit board and manufacturing method thereof

The present invention relates to a ceramic circuit board.

Most electronic components generate heat during operation. Without good thermal and heat dissipation mechanisms, these electronic components will reduce their efficiency with temperature rise, and even their service life will be shortened. Taking a light emitting diode (LED) as an example, the luminous efficiency of the current LED has been increased to more than 30 lm/W, and it is expected to increase to more than 120 lm/W in the future. As the luminous efficiency increases, the heat dissipation problem of the light-emitting diode is also becoming more and more serious. When the light-emitting diode increases with current, the junction temperature (T _j ) increases, and when T _{j is} too high, the output efficiency and lifetime of the light-emitting diode will decrease.

A substrate of a printed circuit board made of glass fiber, also known as a FR4 printed circuit board, has a heat transfer coefficient of about 0.36 W/mK. For light-emitting diodes, the FR4 glass substrate is only suitable for low-power light-emitting diodes.

For electronic components having high heat-generating power such as high-power light-emitting diodes, a circuit board having a metal having a high thermal conductivity (for example, aluminum or copper) as a substrate has been used, that is, a so-called metal core printed circuit board ( Metal-core printed circuit board, MCPCB). Such a circuit board is a conductor due to the metal substrate itself, and an insulator must be used for insulation between the metal substrate and the wire layer to prevent the wire layer from being electrically connected to the metal substrate. However, the metal core printed circuit board mostly uses a polymer material as the insulating layer material, and the thermal conductivity of the polymer material insulating layer is only 0.2 to 0.5 W/mK and has heat resistance problems. Therefore, the original metal substrate with excellent thermal conductivity forms a thermal resistance after the addition of the polymer material insulating layer, which greatly reduces the heat conduction efficiency of the entire circuit board, resulting in a thermal conductivity of the metal core printed circuit board of only 1 to 2.2 W/ mK.

A ceramic material having high heat conductivity and excellent insulating properties such as aluminum nitride or aluminum oxide is used as a substrate, and a circuit board on which a wiring layer is coated is used. Circuit boards made of ceramic substrates are currently classified into HTCC (High Temperature Co-fired Multilayer Ceramic Substrate), LTCC (Low Temperature Co-fired Multilayer Ceramic Substrate), DBC (Direct Bonded Copper Ceramic Substrate), and DPC (Direct Copper Clad). Four kinds of ceramic substrates, etc., according to different process heat transfer coefficient between 2~220 W/mK. The method of manufacturing/forming a wire on a ceramic substrate directly affects the accuracy of the wire, the surface roughness, the alignment accuracy, and the like. Therefore, in the fine line requirements of high-power, small-sized electronic components (for example, LEDs), process resolution has become one of the important items that must be considered. Both LTCC and HTCC use thick film printing technology to complete the line production. Thick film printing itself is limited by the tension of the screen. In general, the surface of the line is rough, and it is easy to cause inaccurate alignment and excessive tolerance. In addition, LTCC and HTCC adopt multi-layer ceramic laminate sintering process, and the shrinkage ratio problem needs to be considered, which makes the process resolution more limited. Although DBC prepares metal lines by lithography process, the lower limit of copper thickness is about 150~300μm due to its process capability limitation, which makes the upper limit of resolution of metal lines only between 150~300μm (in aspect ratio). 1:1 is the standard). DPC is made by the thin film process. It uses vacuum coating and yellow lithography process to make the circuit on the substrate more precise and the surface flatness is high. Then the plating/electroless plating method is used to increase the thickness of the circuit. In general, the resolution of a DPC metal line is between 10 and 50 μm under the principle that the metal line aspect ratio is 1:1.

Circuit boards using ceramic materials as heat-dissipating substrates have been a trend. However, the understanding of the prior art of ceramic circuit boards shows that there is still a need for a new ceramic circuit board architecture to meet the requirements of high resolution and low manufacturing cost of the wires of the circuit board.

Accordingly, one aspect of the present invention is directed to providing a ceramic circuit board. In particular, the ceramic circuit board according to the present invention has a higher wire resolution and a lower manufacturing cost than the prior art.

A ceramic circuit board according to a preferred embodiment of the present invention, comprising a ceramic substrate and at least one wire. The ceramic substrate has an upper surface. In particular, the ceramic substrate has at least one trench corresponding to at least one wire and formed on the upper surface. The at least one wire is formed by filling a metal material with the at least one trench.

In a specific embodiment, the ceramic substrate may be selected from the group consisting of alumina (Al ₂ O ₃ ), aluminum nitride (AlN), tantalum carbide (SiC), yttrium oxide (SiO ₂ ), yttrium oxide (BeO), nitrogen. It is formed by bismuth (Si ₃ N ₄ ) or other ceramic materials with high thermal conductivity and good insulation properties.

In a specific embodiment, the metal material may be copper, copper alloy, aluminum, aluminum alloy, zinc, zinc alloy, tin, tin alloy, lead, lead alloy, nickel, nickel alloy, iron, iron alloy, silver, gold or Other commercially available metal materials with good electrical conductivity.

In one embodiment, one of the at least one trench has a width of about 50 μm to 500 μm.

In a method of fabricating a ceramic circuit board in accordance with a preferred embodiment of the present invention, a ceramic substrate is first prepared, wherein the ceramic substrate has an upper surface and at least one trench formed on the upper surface. Finally, the method according to the invention fills the at least one trench with a metallic material to form at least one wire.

In one embodiment, the filling of the at least one trench to form the at least one wire is performed by first stamping a metal foil into the at least one trench, and then removing the metal material. Excess metal foil.

In another embodiment, the filling of the at least one trench to form the at least one wire is performed by first filling the powder formed of the metal material into the at least one trench, and then filling the The powder of the metal material in the at least one groove is melted and solidified.

In another embodiment, filling the at least one trench with the metal material to form the at least one wire is first injecting the molten material of the metal material into the at least one trench, and then injecting the at least one The melt of the metallic material in the trench solidifies.

Compared with the prior art of ceramic circuit boards, the ceramic circuit board according to the present invention has the advantages of high precision of the wires and low manufacturing cost.

The advantages and spirit of the present invention will be further understood from the following embodiments and the accompanying drawings.

The present invention provides a ceramic circuit board and a method of manufacturing the same. In particular, the ceramic circuit board according to the present invention is different from the prior art in that the wire has high resolution and low manufacturing cost. The features, spirits, advantages, and implementations of the present invention are fully described in the following detailed description of the preferred embodiments of the invention.

Please refer to FIG. 1 and FIG. 2, which is a schematic view showing the appearance of a ceramic circuit board 1 according to a preferred embodiment of the present invention. Fig. 2 is a cross-sectional view of the ceramic circuit board 1 in Fig. 1 taken along line A-A in Fig. 1.

As shown in FIGS. 1 and 2, a ceramic circuit board 1 according to a preferred embodiment of the present invention includes a ceramic substrate 10 and at least one wire 12. The ceramic substrate 10 has an upper surface 102. In particular, the ceramic substrate 10 has at least one trench 104 corresponding to at least one of the wires 12 and formed on the upper surface 102. The at least one wire 12 is formed by filling a metal material with the at least one trench 104.

It should be emphasized that the resolution of the at least one wire 12 is achieved by a pre-formed trench 104, rather than by a thick film technique with poor resolution or by a thin film technology that is costly to manufacture. That is, the width and depth of the at least one wire 12 are equal to the width and depth of the at least one groove.

In one embodiment, the ceramic substrate 10 may be made of aluminum oxide (Al ₂ O ₃ ), aluminum nitride (AlN), tantalum carbide (SiC), yttrium oxide (SiO ₂ ), beryllium oxide (BeO), and nitrided.矽 (Si ₃ N ₄ ) or other ceramic materials with high thermal conductivity and good insulation properties.

In a specific embodiment, the metal material may be copper, copper alloy, aluminum, aluminum alloy, zinc, zinc alloy, tin, tin alloy, lead, lead alloy, nickel, nickel alloy, iron, iron alloy, silver, gold or Other commercially available metal materials with good electrical conductivity.

In one embodiment, as shown in FIG. 2, the width w of the main elongated trench in the at least one trench 104 is about 50 μm to 500 μm. This is the subsequent formation

In one embodiment, as shown in FIG. 2, the depth d of the at least one trench 104 is about 25 μm to 300 μm.

Referring to FIG. 3A, FIG. 3B and FIG. 2, the drawings schematically illustrate a ceramic circuit board 1 as shown in FIG. 2 according to a preferred embodiment of the present invention. Methods.

As shown in Fig. 3A, first, a ceramic substrate 10 is prepared in accordance with the method of the present invention. The ceramic substrate 10 has an upper surface 102. In particular, the ceramic substrate 10 also has at least one trench 104 formed on the upper surface 102. The at least one trench 104 may form a trench on the green embryo of the ceramic substrate 10, and the green groove of the ceramic substrate 10 is sintered, and the groove on the green embryo forms the at least one high trench as the raw embryo shrinks. 104. The at least one trench 104 may also be processed after the ceramic substrate 10 is completed.

Finally, in accordance with the method of the present invention, the at least one trench 104 is filled with a metal material to form at least one of the wires 12, i.e., the ceramic circuit board 1 as shown in Fig. 2 is completed.

In a specific embodiment, as shown in FIG. 3B, filling the at least one trench 104 with a metal material to form the at least one wire 12 is performed by first stamping the metal material into the metal foil 14. In the at least one trench 104, the excess metal foil 14 is removed, that is, the ceramic circuit board 1 as shown in FIG. 2 is completed.

In another embodiment, filling the at least one trench 104 with a metal material to form the at least one wire 12 is performed by first filling a powder formed of the metal material into the at least one trench 104. The powder of the metal material filled in the at least one trench 104 is melted and solidified to complete the ceramic circuit board 1 as shown in FIG.

In another embodiment, filling the at least one trench 104 with a metal material to form the at least one wire 12 is performed by injecting a molten material of the metal material into the at least one trench 104 and then implanting the metal material. The melt of the metal material in the at least one trench 104 is solidified, that is, the ceramic circuit board 1 as shown in FIG. 2 is completed.

Compared with the prior art of ceramic circuit boards, the ceramic circuit board according to the present invention has the advantages of high precision of the wires and low manufacturing cost.

From the above detailed description, the ceramic circuit board according to the present invention can be clearly understood, which has the advantages of high resolution of the wire and low manufacturing cost, unlike the prior art.

The features and spirit of the present invention will be more apparent from the detailed description of the preferred embodiments. On the contrary, the intention is to cover various modifications and equivalents within the scope of the invention as claimed. Therefore, the scope of the patented scope of the invention should be construed as broadly construed in the

1. . . Ceramic circuit board

10. . . Ceramic substrate

102. . . Upper surface of ceramic substrate

104. . . Trench

12. . . wire

14. . . Metal foil

w. . . Width of the groove

d. . . Depth of the groove

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view showing the appearance of a ceramic circuit board in accordance with a preferred embodiment of the present invention.

Fig. 2 is a cross-sectional view of the ceramic circuit board of Fig. 1 taken along line A-A of Fig. 1.

3A and 3B are diagrams schematically showing a method of manufacturing a ceramic circuit board as shown in Fig. 2 in accordance with a preferred embodiment of the present invention.

1. . . Ceramic circuit board

10. . . Ceramic substrate

102. . . Upper surface of ceramic substrate

104. . . Trench

12. . . wire

w. . . Width of the groove

d. . . Depth of the groove

Claims (10)

A ceramic circuit board comprising: a ceramic substrate having an upper surface; and at least one wire having at least one wire corresponding to the at least one wire and formed on the upper surface, the at least one wire being A metal material fills the at least one trench to form. The ceramic circuit board according to claim 1, wherein the ceramic substrate is selected from the group consisting of alumina (Al ₂ O ₃ ), aluminum nitride (AlN), tantalum carbide (SiC), yttrium oxide (SiO ₂ ), and cerium oxide. One of the group consisting of (BeO) and tantalum nitride (Si ₃ N ₄ ) is formed. The circuit board according to claim 2, wherein the metal material is selected from the group consisting of copper, copper alloy, aluminum, aluminum alloy, zinc, zinc alloy, tin, tin alloy, lead, lead alloy, nickel, nickel alloy, iron, iron alloy. One of the groups of silver, gold, and gold. The circuit board of claim 2, wherein one of the at least one trench has a width of about 50 μm to 500 μm. A method of manufacturing a ceramic circuit board comprising the steps of: (a) preparing a ceramic substrate, wherein the ceramic substrate has an upper surface and at least one trench formed on the upper surface; and (b) a metal material Filling the at least one trench to form at least one wire. The method of claim 5, wherein the ceramic substrate is selected from the group consisting of alumina (Al ₂ O ₃ ), aluminum nitride (AlN), tantalum carbide (SiC), yttrium oxide (SiO ₂ ), yttrium oxide (BeO). And one of a group consisting of tantalum nitride (Si ₃ N ₄ ) selected from the group consisting of copper, copper alloy, aluminum, aluminum alloy, zinc, zinc alloy, tin, tin alloy, lead One of a group of lead alloys, nickel, nickel alloys, iron, iron alloys, silver, and gold. The method of claim 6, wherein one of the at least one trench has a width of about 50 μm to 500 μm. The method of claim 7, wherein the step (b) is performed by: stamping the metal material into a metal foil into the at least one trench; and removing the excess metal foil. The method of claim 7, wherein the step (b) is performed by: injecting a powder formed of the metal material into the at least one trench; and filling the metal into the at least one trench The powder of the material is solidified after melting. The method of claim 7, wherein the step (b) is performed by: injecting a molten material of the metal material into the at least one trench; and melting the metal material injected into the at least one trench The soup is solidified.