CN101567326B - Printed circuit board and method of forming the same - Google Patents

Abstract

The embodiment of the invention discloses a printed circuit board and a forming method thereof. The method comprises providing a carrier; forming a first circuit on the carrier; depositing a film on the carrier plate; building an electronic part on the substrate by using the film and electrically connecting the electronic part with the first circuit; forming a dielectric layer to cover the electronic component in a blanket manner; and removing the carrier plate. Embodiments of the present invention help to reduce the size of the final electronic product.

Description

Printed circuit board and method of forming the same

technical field

The invention relates to a printed circuit board and its forming method, in particular to a printed circuit board embedded with electronic parts and its forming method.

Background technique

A printed circuit board (printed circuit board) is a mechanism that constitutes a circuit pattern interconnected between electronic components. FIG. 1 is a schematic diagram of interconnection between a traditional printed circuit board 10 and electronic components such as integrated circuits 20 and passive components 30 . As shown in the figure, it is known that the interconnection between the printed circuit board 10 and the integrated circuit 20 adopts a surface mount method, wherein the integrated circuit 20 is an electronic component that has been packaged and has pins 21, and the pins 21 and 21 are connected by soldering. The lines 11 of the printed circuit board 10 are connected to each other to complete the interconnection.

The current trend of thin, light and small electronic products has made the traditional printed circuit board 10 gradually unable to meet the requirements. For example, since the electronic components are mounted on the surface of the printed circuit board 10, the printed circuit board 10 must provide a sufficient surface area for them to use, thereby limiting the reduction in size thereof. Furthermore, it is known that the integrated circuit 20 installed on the printed circuit board 10 is usually a packaged product, so its volume will be much larger than that of the original unpackaged bare core, which also makes the final electronic product The size reduction is limited. Therefore, there is a need for an improved structure and method to solve the known problems.

Contents of the invention

The present invention provides a printed circuit board embedded with electronic parts. The method is to form a circuit on a temporary carrier board using a printed circuit board process, and then directly build electronic parts on the temporary carrier board, such as diodes, transistors and other optoelectronic components. Semiconductors, etc., and electrically connect this circuit to this electronic part. Then, the circuit and the electronic parts are packaged together with a suitable insulating material. After the packaging is completed, the temporary carrier board is removed.

The present invention has at least the following characteristics that help reduce the size of the final electronic product: the electronic parts are buried in the packaging insulating layer; After printing onto the package insulation, the temporary carrier is removed to reduce thickness.

According to an embodiment, the present invention provides a method for forming a printed circuit board, including providing a carrier board; forming a first circuit on the carrier board; depositing a film on the carrier board; using the film to construct an electronic component on the carrier board On the top, the electronic parts are electrically connected to the first circuit; a dielectric layer is blanket-formed to cover the electronic parts; a part of the dielectric layer is removed to expose an upper surface of the electronic parts; a second circuit is formed on the dielectric layer On, the second circuit is electrically connected with electronic components; an insulating layer is formed to cover the second circuit and the dielectric layer; and the carrier board is removed.

According to another embodiment, the present invention provides a method for forming a printed circuit board, including providing a carrier board; forming a first circuit on the carrier board; building an electronic component on the carrier board, and the electronic component is electrically connected to the first circuit ; Blanket-type formation of a dielectric layer to cover the electronic components; removing a part of the dielectric layer to expose an upper surface of the electronic components; forming a second circuit on the dielectric layer, the second circuit electrically connected to the electronic components ; forming an insulating layer to cover the second circuit and the dielectric layer; and removing the carrier.

Description of drawings

FIG. 1 shows a schematic diagram of a known interconnection of a printed circuit board and electronic components.

2A to 2I are schematic diagrams of the manufacturing process of the printed circuit board embedded with electronic components according to the first embodiment of the present invention.

3A to 3D are schematic diagrams of the manufacturing process of the printed circuit board embedded with electronic components according to the second embodiment of the present invention.

4A to 4C are schematic diagrams of the manufacturing process of the printed circuit board embedded with electronic components according to the third embodiment of the present invention.

Explanation of reference signs

10 printed circuit board

11 Lines

20 integrated circuits

21 pins

30 passive components

200 carrier board

201 First Line

202 film

202a One end

203 Luminous structure layer

203a upper surface

204 The first electrical semiconductor layer

205 luminous layer

206 Second electrical semiconductor layer

210 Dielectric layer

220 Second Line

230 insulation layer

300 carrier board

301 First Line

302 film

302a One end

303 Transistor structure

303a upper surface

304 source

305 drain

306 Gate insulating layer

307 grid

310 Dielectric layer

320 Second Line

330 color edge layer

400 carrier board

401 first line

403 Electroluminescent structure

403a upper surface

404 electron injection layer

405 Electronic conducting layer

406 electroluminescent layer

407 hole transport layer

408 hole injection layer

410 Dielectric layer

420 Second Line

430 insulation layer

Detailed ways

A preferred embodiment of the invention will be exemplified below with reference to the accompanying drawings. Similar elements in the attached figures are provided with the same reference numerals. It should be noted that in order to clearly present the present invention, the components in the accompanying illustrations are not drawn according to the scale of the actual object, and in order to avoid obscuring the content of the present invention, the following description also omits known components, related materials, and related processing techniques .

2A to 2I are the first embodiment of the present invention, illustrating the fabrication process of a printed circuit board with embedded LEDs. Referring to FIG. 2A , a carrier board 200 is provided and a first circuit 201 is formed on the carrier board 200 . The carrier 200 can be any suitable substrate, especially a conductive metal substrate, such as a copper foil substrate or a thin stainless steel alloy plate. The formation of the first circuit 201 can utilize a known printed circuit board process. For example, a dry film can be coated on the carrier 200; then the dry film can be patterned to expose the surface of the underlying carrier 200; then the dry film can be used as a mask to plate a conductive material such as copper nickel equal to the exposed carrier 200 on the surface; then peel off the dry film to form the first circuit 201 .

Referring to FIG. 2B , a thin film 202 is deposited on the carrier 200 . Preferably, the film 202 is directly formed on the surface of the carrier 200 , and the film 202 has an end 202 a connected to the first circuit 201 . The thin film 202 is the growth substrate of the LED to be formed later. Taking growing the epitaxial layer of a light-emitting diode as an example, the material of the thin film 202 can be gallium arsenide (GaAs), indium phosphide (InP), gallium phosphide (GaP), sapphire, silicon carbide (SiC), etc. Film 202 may have a patterned topography. The thin film 202 can be formed by suitable thin film deposition and masking techniques, such as known sputtering, vapor deposition or screen printing techniques.

Referring to FIG. 2C , the film 202 is used as the base, and the light-emitting structure layer 203 is formed on the carrier 200 by known epitaxial technology and semiconductor deposition technology. The light emitting structure layer 203 may include several epitaxial layers such as a first electrical type semiconductor layer 204 , a light emitting layer 205 and a second electrical type semiconductor layer 206 . For example, the first electrical semiconductor layer 204 can be an n-type (Al _x Ga _1-x ) _0.5 In _0.5 P epitaxial layer; the light emitting layer 205 is made of undoped (Al _x Ga _1-x ) _0.5 In _0.5 P epitaxial layer, and the second electrical semiconductor layer 206 can be a p-type (Al _x Ga _1-x ) _0.5 In _0.5 P epitaxial layer. The relative thicknesses of the thin film 202 , the first electrical semiconductor layer 204 and the first circuit 201 can be controlled, so that the first electrical semiconductor layer 204 is electrically connected to the first circuit 201 . It should be noted that the light emitting layer 205 and a second electrical type semiconductor layer 206 cannot contact the first circuit 201 , otherwise the light emitting structure layer 203 will lose its function. In addition to the aforementioned epitaxial layers, the light emitting structure layer 203 may also include other functional structures, such as an ohmic contact layer, a barrier layer, and a reflective layer.

Referring to FIG. 2D , a dielectric layer 210 is blanket formed to cover the light emitting structure layer 203 and the first circuit 201 . The dielectric layer 210 is preferably selected from spin-on-glass, silicone resin, epoxy resin (Epoxy), polyimide (polyimide), or prefluorocyclobutane (prefluorocyclobutane, PFCB) and the like. This step can be accomplished using known precision coating techniques. It should be noted that the light emitting structure layer 203 is not encapsulated before performing this step.

Referring to FIG. 2E , a part of the dielectric layer 210 is removed by a suitable chemical mechanical polishing technique, so that an upper surface 203 a of the light emitting structure layer 203 is exposed. Next, referring to FIG. 2F , a second circuit 220 is formed on the dielectric layer 210 , and the second circuit 220 is electrically connected to the light emitting structure layer 203 through proper control. For example, a patterned dry film can be first formed on the dielectric layer 210 and the upper surface 203a of the light-emitting structure layer 203; then the patterned dry film can be used as a mask to inject conductive material seeds by sputtering technology; then , through this type of electroplating process to form the second circuit 220 on the surface of the dielectric layer 210, and the second circuit 220 contacts the upper surface 203a of the light emitting structure layer 203 at the same time to achieve electrical connection. In addition, a screen printing process can also be used to print conductive materials such as copper paste and silver paste on the dielectric layer 210 to form the second circuit 220 .

Next, referring to FIG. 2G , an insulating layer 230 is blanket formed to connect the second circuit 220 , the light emitting structure layer 203 and the dielectric layer 210 . The material of the insulating layer 230 may be polyester or polyimide, which may contain suitable organic reinforcing materials. The insulating layer 230 can be formed by coating, or the above materials can be pressed into a sheet and pasted on the surface of the second circuit 220 and the light emitting structure layer 203 . The thickness and strength of the insulating layer 230 can be appropriately adjusted so that it is sufficient to serve as a supporting layer for the above-mentioned components, so that the carrier 200 can be removed to form the structure shown in FIG. 2H . The carrier 200 can be removed using known etching techniques.

Figure 2I shows an optional step following Figure 2H. As shown in the figure, the thin film 202 can be removed by etching. Since the thin film 202 may be a light absorbing material, removing it can increase the brightness of the LED. In addition, as shown in the figure, the insulating layer 230 may be properly ground to expose the second circuit 220 as required.

It should be understood from the above that the present invention does not directly glue the completed electronic components (such as generally packaged electronic components) onto the carrier board as a whole. The present invention provides a method for integrating printed circuit board technology with semiconductor technology or other electronic parts technology. In short, the present invention uses the printed circuit board technology to form an external circuit on the carrier board, and then directly uses the semiconductor technology or other electronic parts technology to gradually build the main structure of the electronic parts on the carrier board; and then uses the printed circuit board The process forms another external connection circuit to be electrically connected with the electronic parts. The electronic components of the first embodiment of the present invention are demonstrated with light-emitting diodes, but it should be understood that in addition to light-emitting diodes, the method disclosed in the first embodiment is also applicable to other diodes, such as PN junction diodes, photodiodes, and laser diodes .

3A to 3D illustrate a second embodiment of the present invention. The difference between the second embodiment and the first embodiment is that the embedded electronic component is a transistor. Specifically, as shown in FIG. 3A , a carrier board 300 is provided and a first circuit 301 is formed on the carrier board 300 . Referring next to FIG. 3B , a thin film 302 is deposited on the carrier 300 . Preferably, the film 302 is directly formed on the surface of the carrier 300 , and the film 302 has an end 302 a connected to the first circuit 301 . The thin film 302 is the growth substrate of the semiconductor transistor to be formed later. Taking this as an example, the material of the thin film 302 may be silicon (Si), gallium arsenide (GaAs), indium phosphide (InP), gallium phosphide (GaP), sapphire, silicon carbide (SiC) and the like. The thin film 302 can be formed by suitable known techniques, such as sputtering, vapor deposition, or screen printing.

Referring to FIG. 3C , a transistor structure 303 is formed using known semiconductor technology and suitable semiconductor materials using the thin film 302 as a substrate. The transistor structure 303 includes a source 304 , a drain 305 , a gate insulating layer 306 and a gate 307 , wherein the source 304 and the drain 305 are respectively connected to the first circuit 301 . Subsequent steps in FIG. 3C are similar to the first embodiment. As shown in FIG. 3D , a dielectric layer 310 is blanket formed to cover the flip-chip transistor structure 303 and the first circuit 301 . It should be noted that the transistor structure 303 is not encapsulated before performing this step. Then, a part of the dielectric layer 310 is removed by a suitable chemical mechanical polishing technique, so that an upper surface 303 a of the transistor structure 303 is exposed. Next, a second circuit 320 is formed on the dielectric layer 310 , and the second circuit 320 is electrically connected to the transistor structure 303 through proper control. Next, an insulating layer 330 is blanket formed to connect the second circuit 320 , the transistor structure 303 and the dielectric layer 310 . The thickness and strength of the insulating layer 330 can be properly adjusted so that it is sufficient to serve as a supporting layer for the above-mentioned components, and finally the carrier 300 is removed.

The electronic components of the second embodiment of the present invention are exemplified by MOS transistors, but it should be understood that other transistors such as bipolar transistors and CMOS transistors are also applicable to the present invention.

4A to 4C illustrate a third embodiment of the present invention. The difference between the third embodiment and the previous two embodiments is that the manufacturing method of the electronic components does not include the step of forming thin films 202 and 302 as growth substrates. In other words, non-high-temperature processes can also be used to make the embedded electronic parts of the present invention, such as vacuum evaporation, spin coating or printing process (Printing Process), screen printing (Screen Printing), inkjet printing (Inkjet Printing) And contact printing (Contact Printing) and so on. The electronic component of the third embodiment takes electroluminescence as an example. Specifically, as shown in FIG. 4A , a carrier board 400 is provided and a first circuit 401 is formed on the carrier board 400 . Referring next to FIG. 4B , the electroluminescent body structure 403 is formed using the above-mentioned evaporation, coating or printing techniques combined with appropriate masking techniques. The electroluminescent structure 403 includes an electron injection layer 404 , an electron conducting layer 405 , an electroluminescent layer 406 , a hole transport layer 407 , and a hole injection layer 408 . The material of the electron injection layer 404 can be an organic material doped with an alkaline metal; the electron conduction layer 405 can be an oxadiazole (Oxadiazole), a triazole (Triazoles), or a phenanthroline (Phenanthroline); an electroluminescent layer 406 can be a polymer containing various fluorescent pigments; the hole transport layer 407 can be an allylamine compound; the hole injection layer 408 can be an organic material doped with Lewis acid. Subsequent steps in FIG. 4B are similar to those in the first and second embodiments. As shown in FIG. 4C , a dielectric layer 410 is blanket formed to cover the electroluminescent structure 403 and the first circuit 401 . It should be noted that the electroluminescent structure 403 is not encapsulated before performing this step. Then, a part of the dielectric layer 410 is removed by a suitable chemical mechanical polishing technique, so that an upper surface 403 a of the electroluminescent structure 403 is exposed. Next, a second circuit 420 is formed on the dielectric layer 410 , and the second circuit 420 is electrically connected to the electroluminescent structure 403 through proper control. Next, an insulating layer 430 is blanket formed to connect the second circuit 420 , the electroluminescent structure 403 and the dielectric layer 410 . The thickness of the insulating layer 430 can be properly adjusted so that it is sufficient to serve as a supporting layer for the above components, and finally the carrier 400 is removed.

The electronic parts of the foregoing embodiments of the present invention are demonstrated with light-emitting diodes, transistors, and electroluminescent bodies. However, it should be understood that in addition to these electronic parts, other electronic parts suitable for the above-mentioned process, such as optical fiber conductive parts, are also within the scope of the present invention. middle.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the claims of the present invention; all other equivalent changes or modifications that do not deviate from the spirit disclosed in the present invention should be included in the following applications Thickness patent range.

Claims (8)

1. A method for forming a printed circuit board, comprising: providing a carrier board; forming a first circuit on the carrier; depositing a thin film on the carrier; Using the thin film to build an electronic component on the carrier, the electronic component is electrically connected to the first circuit, wherein the step of using the thin film to build the electronic component on the carrier includes growing an epitaxial structure on the base of the thin film on the film; blanket forming a dielectric layer to enclose the electronic component; removing a portion of the dielectric layer to expose an upper surface of the electronic component; forming a second circuit on the dielectric layer, the second circuit is electrically connected to the electronic component; forming an insulating layer covering the second line and the dielectric layer; and remove the carrier board, Wherein the method does not include directly adhering the electronic component integrally to the carrier, Wherein before the step of blanket forming the dielectric layer to cover the electronic component, the electronic component is not encapsulated. 2. The method of claim 1, wherein the carrier is a metal substrate, and the step of forming the first circuit utilizes electroplating. 3. The method of claim 1, wherein the material of the thin film is selected from the group consisting of silicon, gallium arsenide, indium phosphide, gallium phosphide, sapphire, and silicon carbide. 4. The method of claim 1, wherein the step of depositing the thin film on the carrier utilizes sputtering, chemical vapor deposition or screen printing. 5. The method of claim 1, wherein the electronic component is a diode. 6. The method of claim 5, wherein the diode comprises a PN junction diode, a photodiode, a light emitting diode, and a laser diode. 7. The method as claimed in claim 1, wherein the step of using the thin film to construct the electronic component on the carrier comprises forming a transistor structure on the carrier using the thin film as a base by using a semiconductor process. 8. A printed circuit board manufactured by the method of claim 1. the

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