Electronic device

Abstract

An electronic device including a circuit substrate and a first filling layer is provided. The circuit substrate includes a base and a first pad and a second pad disposed on the base. The first filling layer includes a first portion located between the first pad and the second pad. The first pad and the second pad are suitable for connecting two electrodes of a first electronic component, respectively. The first filling layer has an absorption rate greater than

Description

Technical Field

[0001] This invention relates to an electronic device. Prior Technology

[0002] Electronic devices typically contain a large number of electronic components, which can be bonded to the substrate using laser light. However, during the laser scanning process, non-bonded areas can also be heated by the laser light, causing damage to components in that area or short circuits in the electronic device. Summary of the Invention

[0003] This invention provides an electronic device in which the non-junctional area is protected, resulting in a high yield.

[0004] According to an embodiment of the present invention, an electronic device is provided, including a circuit board and a first filling layer. The circuit board includes a substrate and a first pad and a second pad disposed on the substrate. The first filling layer includes a first portion located between the first pad and the second pad. The first pad and the second pad are adapted to respectively connect two electrodes of a first electronic component. The first filling layer has an absorption rate of greater than 80% for light in the range of 200 nm to 355 nm.

[0005] According to another embodiment of the present invention, an electronic device is provided, including a circuit board and a first filling layer. The circuit board includes a substrate and a first pad, a second pad, a third pad, and a fourth pad disposed on the substrate. The first filling layer includes a first portion located between the first pad and the second pad and a second portion located between the third pad and the fourth pad. The first pad and the second pad are adapted to connect two electrodes of a first electronic element, respectively, and the third pad and the fourth pad are adapted to connect two electrodes of a second electronic element, respectively. The second portion of the first filling layer includes a top surface defining a first virtual reference plane, and the first portion of the first filling layer includes at least one concave surface located between the first virtual reference plane and the substrate.

[0006] Based on the above, the electronic device provided in this embodiment of the invention utilizes a first filling layer to absorb laser light used to break the bond between the pad and the electrode, thereby preventing the laser light from damaging the components in the substrate.

[0007] To make the above features and advantages of the present invention more apparent and understandable, specific embodiments are described below in conjunction with the accompanying drawings for detailed explanation. Simple Explanation of the Diagram

[0008] Figure 1A shows a schematic diagram of the electronic device according to the first embodiment of the present invention in a first state, Figure 1B shows a schematic diagram of the electronic device according to the first embodiment of the present invention in a second state, and Figure 1C shows a schematic diagram of the electronic device according to the first embodiment of the present invention in a third state. Figure 2A shows a schematic diagram of the electronic device according to the second embodiment of the present invention in a first state, Figure 2B shows a schematic diagram of the electronic device according to the second embodiment of the present invention in a second state, and Figure 2C shows a schematic diagram of the electronic device according to the second embodiment of the present invention in a third state. Figure 3 shows a schematic diagram of an electronic device according to some embodiments of the present invention. Figure 4 shows a schematic diagram of an electronic device according to some embodiments of the present invention. Implementation

[0009] Referring to Figures 1A, 1B, and 1C, Figure 1A shows a schematic diagram of the electronic device according to the first embodiment of the present invention in a first state, Figure 1B shows a schematic diagram of the electronic device according to the first embodiment of the present invention in a second state, and Figure 1C shows a schematic diagram of the electronic device according to the first embodiment of the present invention in a third state.

[0010] The electronic device 1 of this first embodiment includes a circuit board 10, a filler layer SA1, electronic components 201 and 202. The circuit board 10 includes a substrate 100, pads 101, 102, 103, and 104, wherein pads 101 and 102 are arranged in pairs, and pads 103 and 104 are arranged in pairs. The filler layer SA1 includes a first portion SA11 located between pads 101 and 102 and a second portion SA12 located between pads 103 and 104, wherein the first portion SA11 and the second portion SA12 are made of the same material, and the top surface TP1 of the first portion SA11 is substantially coplanar with the top surface TP2 of the second portion SA12. The electronic component 201 includes electrodes 201A and 201B. The electronic component 202 includes electrodes 202A and 202B. Pad 101 is connected to electrode 201A, pad 102 is connected to electrode 201B, pad 103 is connected to electrode 202A, and pad 104 is connected to electrode 202B.

[0011] The filler layer SA1 may, for example, comprise (meth)acrylate copolymers and the like. In a preferred embodiment, the filler layer SA1 may have an absorption rate greater than 80% for light in the 200 nm to 355 nm range. In a more preferred embodiment, the filler layer SA1 may have an absorption rate greater than 95% for light in the 200 nm to 355 nm range.

[0012] When electronic component 201 of electronic device 1 is damaged, light (e.g., laser light) in the range of 200 nm to 355 nm is needed to break the bonding between pad 101 and electrode 201A and between pad 102 and electrode 201B in order to remove the damaged electronic component 201. In a comparative example, electronic device 1 does not have a filling layer SA1. When laser light irradiates the surface of substrate 100 between pads 101 and 102, it will cause damage to components of substrate 100 near that surface.

[0013] In contrast, in this first embodiment, a filling layer SA1 (i.e., a first portion SA11 of the filling layer SA1) is provided on the surface of the substrate 100 between the pads 101 and 102, and the filling layer SA1 has an absorption rate of more than 80% for laser light in the range of 200 nm to 355 nm. Therefore, the first portion SA11 of the filling layer SA1 can absorb the laser light used to remove the electronic component 201, preventing the surface of the substrate 100 between the pads 101 and 102 from being excessively irradiated by laser light, which could damage the components within the substrate 100.

[0014] In some embodiments, the first portion SA11 of the filling layer SA1 can generate a gas containing carbon dioxide and carbon monoxide, and a gas containing water molecules, after being irradiated with laser light in the range of 200 nm to 355 nm, but is not limited thereto.

[0015] In some embodiments, the first portion SA11 of the filling layer SA1 can form a concave surface CS0 after being irradiated by laser light, as shown in FIG1B. The concave surface CS0 is located between a virtual reference surface BP1 and the substrate 100, and the virtual reference surface BP1 is coplanar with the top surface TP2 of the second portion SA12, wherein the second portion SA12 is not irradiated by laser light. In other words, the first portion SA11 after being irradiated by laser light forms a concave surface CS0 that is recessed relative to its top surface TP1.

[0016] However, the present invention is not limited to the structure shown in FIG1B. In some embodiments, the first part SA11 after being irradiated by laser light can form a plurality of concave surfaces (concave surface CS1 and concave surface CS2 as shown in FIG1C), wherein these concave surfaces CS1 and CS2 are located between the virtual reference surface BP1 and the substrate 100.

[0017] It should be further noted that although in the structures shown in Figures 1B and 1C, the surface of the substrate 100 between the pads 101 and 102 is completely covered by the filler layer SA1, the present invention is not limited thereto. In some embodiments, at least a portion of the surface of the substrate 100 between the pads 101 and 102 may be exposed by the filler layer SA1.

[0018] In some embodiments, the filler layer SA1 has an absorption rate of less than 5% for light in the range of 900 nm to 1000 nm that can be used to bond electronic components 201, 202 and circuit substrate 10. Accordingly, the deterioration of the filler layer SA1 during the manufacturing process of bonding electronic components 201, 202 and circuit substrate 10 can be avoided.

[0019] In some embodiments, the filler layer SA1 can also absorb the gas generated by disrupting the bonding between the pad 101 and the electrode 201A, reducing the amount of solder residue and the residue of electronic components 201.

[0020] In the structures shown in Figures 1A to 1C, the filler layer SA1 may further include a third portion SA13, wherein the first portion SA11, the second portion SA12, and the third portion SA13 comprise the same material. The first portion SA11 and the second portion SA12 are both disposed between pairs of pads, while the third portion SA13 is not disposed between pairs of pads. However, the electronic device provided by this invention is not limited to the above-described structure; in some embodiments, the filler layer SA1 may only be disposed between pairs of pads.

[0021] To fully illustrate the various embodiments of the present invention, other embodiments will be described below. It must be noted that the following embodiments use the same element reference numerals and some content as those in the foregoing embodiments, with the same reference numerals representing the same or similar elements, and descriptions of identical technical content omitted. For explanations of the omitted parts, please refer to the foregoing embodiments; these will not be repeated in the following embodiments.

[0022] Referring to Figures 2A, 2B, and 2C, Figure 2A shows a schematic diagram of the electronic device according to the second embodiment of the present invention in a first state, Figure 2B shows a schematic diagram of the electronic device according to the second embodiment of the present invention in a second state, and Figure 2C shows a schematic diagram of the electronic device according to the second embodiment of the present invention in a third state.

[0023] The electronic device 2 of this second embodiment further comprises a filling layer SA2 on the filling layer SA1 compared to the aforementioned electronic device 1. The filling layer SA2 includes a first portion SA21 located between the pad 101 and the pad 102 and a second portion SA22 located between the pad 103 and the pad 104, wherein the first portion SA21 and the second portion SA22 are made of the same material, and the top surface TP3 of the first portion SA21 is substantially coplanar with the top surface TP4 of the second portion SA22.

[0024] The filler layer SA2 may, for example, comprise a tackifying resin, wherein the tackifying resin may include phenolic hydroxyl groups, hydroxymethyl groups, carboxyl groups, ester bonds, ether bonds, and the like. In some embodiments, the filler layer SA2 has an absorption rate of less than 20% for light in the range of 200 nm to 355 nm. Accordingly, when it is necessary to use laser light in the range of 200 nm to 355 nm to break the adhesion between the pad 101 and the electrode 201A and the adhesion between the pad 102 and the electrode 201B, the laser light can penetrate the first portion SA21 of the filler layer SA2 and be absorbed by the first portion SA11 of the filler layer SA1. Accordingly, the components within the substrate 100 can be protected by the first portion SA11 of the filler layer SA1 as described in the first embodiment, and the first portion SA21 of the filler layer SA2 can further block the gas generated by the first portion SA11 irradiated by the laser light, preventing the gas from contaminating the electronic device 2.

[0025] Specifically, referring to Figures 2A and 2B, when it is necessary to use laser light in the range of 200 nm to 355 nm to break the adhesion between pad 101 and electrode 201A, and between pad 102 and electrode 201B, the laser light can penetrate the first portion SA21 of the filling layer SA2, and be absorbed by the first portion SA11 of the filling layer SA1. After being irradiated by laser light, the first portion SA11 of the filling layer SA1 can form a concave surface CS0 (as shown in Figure 2B) and generate gas. The highly viscous filling layer SA2 can bulge upwards to form a cavity S12 surrounded by the first portions SA11 and SA21 of the filling layer SA2. The gas generated by the first portion SA11 of the filling layer SA1 can be confined within the cavity S12, thus preventing contamination of the electronic device 2. As shown in Figure 2B, the highly viscous first portion SA21, under pressure from the gas within the cavity S12, can form a convex surface VS0. A virtual reference surface BP2 is located between the convex surface VS0 and the substrate 100, and the virtual reference surface BP2 is coplanar with the top surface TP4 of the second part SA22, wherein the second part SA22 of the filling layer SA2 is not irradiated by laser light.

[0026] However, the present invention is not limited to the structure shown in FIG2B. In some embodiments, the first part SA21 after being irradiated by laser light can form a plurality of convex surfaces (convex surfaces VS1 and VS2 as shown in FIG2C) and a plurality of cavities S13 that protrude relative to its top surface TP3, wherein the virtual reference surface BP2 is located between these convex surfaces VS1, VS2 and the substrate 100.

[0027] In the structures shown in Figures 2A to 2C, the filler layer SA2 may further include a third portion SA23, wherein the first portion SA21, the second portion SA22, and the third portion SA23 comprise the same material. The first portion SA21 and the second portion SA22 are both disposed between pairs of pads, while the third portion SA23 is not disposed between pairs of pads. However, the electronic device provided by this invention is not limited to the above-described structure; in some embodiments, the filler layer SA2 may only be disposed between pairs of pads.

[0028] Furthermore, the present invention is not limited to the electronic device 2 shown in FIG. 2A. In some embodiments, the first portion SA11 and the first portion SA21 between pad 101 and pad 102, and the second portion SA12 and the second portion SA22 between pad 103 and pad 104, can be configured as shown in FIG. 3 and FIG. 4, which will be described below. For ease of understanding, the structures shown in FIG. 3 and FIG. 4 will only be described with reference to the first portion SA11 and the first portion SA21 between pad 101 and pad 102.

[0029] Referring to FIG3, a schematic diagram of an electronic device according to some embodiments of the present invention is shown. The electronic device 3 of this embodiment has a substantially the same structure as the electronic device 2 of the second embodiment, the main difference being that the surface of the substrate 100 of the electronic device 3 between the pads 101 and 102 is exposed by a first portion SA11 of the filling layer SA1. Accordingly, when it is necessary to use laser light in the range of 200 nm to 355 nm to break the adhesion between the pads 101, 102 and the corresponding electrodes, the position of the upwardly protruding portion of the first portion SA21 of the filling layer SA1 can be determined by the position of the first portion SA11 of the filling layer SA1. In the structure shown in FIG3, the upwardly protruding portion of the first portion SA21 of the filling layer SA2 is located in the center of the region between the pads 101 and 102.

[0030] Figure 4 shows a schematic diagram of an electronic device according to some embodiments of the present invention. The electronic device 4 of this embodiment has a substantially the same structure as the electronic device 2 of the second embodiment, the main difference being that the first portion SA11 of the filling layer SA1 of the electronic device 4 has a first thickness T1 in its central portion and a second thickness T2 in its peripheral portion, the first thickness T1 being greater than the second thickness T2. Accordingly, when it is necessary to use laser light in the range of 200 nm to 355 nm to break the adhesion between the pads 101, 102 and the corresponding electrodes, the upwardly protruding portion of the first portion SA21 of the filling layer SA2 can be located in the center of the region between the pads 101 and 102.

[0031] In summary, the electronic device provided by the embodiments of the present invention utilizes a filling layer (first filling layer) to absorb laser light used to break the bond between the pad and the electrode, thereby preventing the laser light from damaging the components in the substrate; the electronic device also utilizes another filling layer (second filling layer) to limit the gas generated by the first filling layer, thereby preventing the electronic device from being contaminated by the gas.

[0032] 1, 2, 3, 4: Electronic devices 10: Circuit board 100: Base 101: Connecting pad 102: Connecting pad 103: Connecting pad 104: Connecting pad 201: Electronic Components 201A: Electrode 201B: Electrode 202: Electronic Components 202A: Electrode 202B: Electrode BP1: Virtual reference plane BP2: Virtual reference surface CS0: Concave surface CS1: Concave surface CS2: Concave SA1: Filler layer SA11: Part One SA12: Part Two SA13: Part Three SA2: Filler layer SA21: Part One SA22: Part Two SA23: Part Three S12: Cavity S13: Cavity TP1: Top surface TP2: Top surface TP3: Top surface TP4: Top surface T1: First thickness T2: Second thickness VS0: Convex surface VS1: Convex VS2: Convex

Claims

1. An electronic device comprising: A circuit board includes a substrate, and a first pad and a second pad disposed on the substrate; and a first filling layer, including a first portion located between the first pad and the second pad, wherein the first pad and the second pad are adapted to respectively connect to two electrodes of a first electronic element, and wherein the first filling layer has an absorption rate of more than 80% for light in the range of 200 nm to 355 nm, and wherein the first filling layer has an absorption rate of less than 5% for light in the range of 900 nm to 1000 nm.

2. The electronic device of claim 1, wherein the first filling layer has an absorption rate of greater than 95% for light in the range of 200 nm to 355 nm.

3. The electronic device as claimed in claim 1, wherein the first filler layer comprises a (meth)acrylate copolymer.

4. The electronic device of claim 1, wherein when the first filling layer is irradiated with light in the range of 200 nm to 355 nm, the first filling layer generates a gas, and the gas includes at least one of carbon dioxide, carbon monoxide, and water molecules.

5. The electronic device of claim 1 further includes a second filling layer disposed on the first filling layer, wherein the second filling layer has an absorption rate of less than 20% for light in the range of 200 nm to 355 nm.

6. The electronic device of claim 5, wherein a portion of the surface of the substrate between the first pad and the second pad is exposed by the first portion of the first filler layer.

7. The electronic device of claim 5, wherein the first portion of the first filling layer has a first thickness and a second thickness, the first thickness being different from the second thickness.

8. The electronic device as claimed in claim 5, wherein the second filler layer comprises a tackifying resin.

9. An electronic device comprising: A circuit board includes a substrate and a first pad, a second pad, a third pad and a fourth pad disposed on the substrate; The first filling layer includes a first portion located between the first pad and the second pad, and a second portion located between the third pad and the fourth pad, wherein the first pad and the second pad are adapted to connect to two electrodes of a first electronic element, and the third pad and the fourth pad are adapted to connect to two electrodes of a second electronic element, wherein the second portion of the first filling layer includes a top surface defining a first virtual reference plane, and the first portion of the first filling layer includes at least one concave surface located between the first virtual reference plane and the substrate, wherein the first filling layer has an absorption rate of less than 5% for light in the range of 900 nm to 1000 nm.

10. The electronic device of claim 9, wherein the first filler layer comprises a (meth)acrylate copolymer.

11. The electronic device of claim 9 further includes a second filler layer disposed on the first filler layer and including a first portion between the first pad and the second pad and a second portion between the third pad and the fourth pad, wherein the second portion of the second filler layer includes a top surface defining a second virtual reference surface, the first portion of the second filler layer includes at least one convex surface, and the second virtual reference surface is located between the substrate and the at least one convex surface.

12. The electronic device of claim 11, wherein there is at least one cavity between the first portion of the second filling layer and the first portion of the first filling layer.

13. The electronic device of claim 11, wherein the second filler layer comprises a tackifying resin.

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