Method for forming a conductive layer, conductive layer, electronic module, and electronic device.

Abstract

To efficiently form shield layers 250, 260 on a top face 102 and a side face 104 of a substrate 100.SOLUTION: A method for forming a shield layer 200 includes: a first application step of applying, by an ink jet head 400, an ink 500 including conductive material 520 to a top face 102 of a substrate 100; and a second application step of applying, by the ink jet head 400, the ink 500 to a side face 104 of the substrate 100.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a method for forming a conductive layer, a conductive layer, an electronic module, and an electronic apparatus. [Background Art]

[0002] Patent Document 1 describes a semiconductor integrated circuit which is mounted on a printed circuit board on which a wiring pattern is formed and connected to said wiring pattern via a plurality of terminals, characterized in that it comprises a shielding part that shields electromagnetic noise provided to cover a surface of the semiconductor integrated circuit opposite the printed circuit board side, and a connecting part for connecting said shielding part and a ground on said printed circuit board.

[0003] Patent Document 2 describes an EMI shield in which a conductive layer includes inkjet printing. [Prior Art Literature] [Patent Literature]

[0004] [Patent Document 1] Japanese Unexamined Patent Publication No. 2001-127211 [Patent Document 2] U.S. Patent No. 9,282,630 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] An object of the present invention is to efficiently form a conductive layer. [Means for Solving the Problem]

[0006] A method for forming a conductive layer according to claim 1 of the present invention is A method for forming a conductive layer using a liquid composition containing a conductive material,The process includes a first application step of applying a liquid composition to the upper surface of an object using an application unit, and a second application step of applying a liquid composition to the side surface of an object using an application unit, wherein in the second application step, the application unit applies the liquid composition to the side surface which has a plurality of protrusions formed on its surface, and the protrusions are such that the density is higher at the bottom than at the top in the conductive layer formed on the side surface. [Effects of the Invention]

[0007] According to claim 1 of the present invention, a conductive layer can be efficiently formed. [Brief explanation of the drawing]

[0008] [Figure 1] This is an explanatory diagram of an electronic device according to an embodiment of the present invention. [Figure 2] This is an explanatory diagram of another electronic device according to the present embodiment. [Figure 3] This is an explanatory diagram of the method for forming an electromagnetic wave shield according to this embodiment. [Figure 4] Another explanatory diagram of the method for forming an electromagnetic shield according to this embodiment. [Figure 5] This diagram illustrates the process of forming the electromagnetic shield according to this embodiment. [Figure 6] This diagram illustrates the electromagnetic shield after its formation according to this embodiment. [Figure 7] Another explanatory diagram illustrating the process of forming the electromagnetic shield according to this embodiment. [Figure 8] This is another explanatory diagram showing the electromagnetic shield after its formation according to this embodiment. [Figure 9] This is an explanatory diagram of the process for forming an electromagnetic shield according to this embodiment. [Figure 10] This is an explanatory diagram of an electromagnetic shield according to an embodiment of this model. [Modes for carrying out the invention]

[0009] Printed wiring boards (PWBs) in their unattached state, used in high-speed communication such as 5G and autonomous driving, and printed circuit boards (PCBs) in their operational state with soldered electronic components, require high reliability, and control technologies using electromagnetic waves generated from electronic components and wiring are known. Furthermore, with the miniaturization and weight reduction of products, PCBs and other components are also required to be thinner and lighter, and technologies for electromagnetic shielding of PCBs and the electronic components used in them are also known.

[0010] In other words, electronic components and electronic devices such as IC chips, capacitors, resistors, diodes, solenoids, and semiconductor packages are sometimes covered with conductive materials such as shielding films, metal caps, conductive paints, or electromagnetic wave absorbers to act as electromagnetic shielding.

[0011] Figure 1 is an explanatory diagram of an electronic device according to an embodiment of the present invention.

[0012] As shown in Figure 1(a), the electronic device 1 includes a shield layer 200 and a protective layer 300 on a substrate 100 formed on the outer surface of a semiconductor package 110. The shield layer 200 is electrically connected to the ground portion 100G included in the semiconductor package 110. The protective layer 300 may be omitted or may be formed integrally with the shield layer 200.

[0013] As shown in Figure 1(b), in this embodiment, the inkjet head 400 ejects ink 500 containing a conductive material onto the surface of the substrate 100, which is placed on the outer circumferential surface of the semiconductor package 110, thereby forming a shield layer 200 on the surface of the substrate 100.

[0014] Here, ink 500 is an example of a liquid composition containing a conductive material, and inkjet head 400 is an example of a dispensing unit that dispenses the liquid composition. Also, shield layer 200 is an example of a conductive layer.

[0015] FIG. 2 is an explanatory diagram of another electronic device according to the present embodiment.

[0016] As shown in FIG. 2(a), the electronic device 1 includes an electronic component 120 and a substrate 130. A connecting portion 125 provided on the electronic component 120 is electrically connected to a wiring 135 provided on the substrate 130 when the electronic component 120 is attached to the substrate 130.

[0017] The electronic component 120 includes a shield layer 200 on a base material 100 formed on an outer peripheral surface. The shield layer 200 is electrically connected to a ground portion 100G provided on the substrate 130 when the electronic component 120 is attached to the substrate 130. The electronic component 120 is an example of an electronic module.

[0018] As shown in FIG. 2(b), in the present embodiment, an inkjet head 400 discharges ink 500 containing a conductive material onto the surface of the base material 100 arranged on the outer peripheral surface of the electronic component 120, thereby forming the shield layer 200 on the surface of the base material 100.

[0019] U.S. Patent No. 9282630 describes an EMI shield in which a conductive layer is formed by inkjet printing, but does not mention efficiently forming the shield layer 200.

[0020] That is, as shown in FIG. 1 and FIG. 2, the shield layer 200 needed to be formed on five surfaces of the base material 100: the top surface, the left and right side surfaces, and the front and rear side surfaces.

[0021] An object of the present embodiment is to efficiently form the shield layer 200 on the base material 100 having a plurality of surfaces.

[0022] FIG. 3 is an explanatory diagram of a method for forming an electromagnetic wave shield according to the present embodiment.

[0023] As shown in Figure 3(a), the inkjet head 400 applies ink 500 to the upper surface 102 of the substrate 100 placed on the mounting table 600, thereby forming a shield layer 250 on the upper surface. This is an example of a first application step in which a liquid composition containing a conductive material is applied to the upper surface of an object by an application unit.

[0024] Next, the mounting platform 600 is moved in the direction of the arrow in the figure. This is an example of a movement process in which the object and the application unit are moved relative to each other in a direction intersecting the direction in which the application unit applies the liquid composition.

[0025] Next, as shown in Figure 3(b), the inkjet head 400 applies ink 500 to the corners 106 of the substrate 100 placed on the mounting table 600, causing the ink 500 to drip onto the side surface 104 of the substrate 100, thereby forming a side shield layer 260.

[0026] Here, the direction in which the inkjet head 400 ejects the ink 500 is the same in Figures 3(a) and 3(b).

[0027] Then, by rotating the mounting base 600 around the vertical axis in the diagram, the inkjet head 400 applies ink 500 to the other three sides 104 of the substrate 100 placed on the mounting base 600, thereby forming the shield layer 260 on the other three sides.

[0028] Figure 4 is another explanatory diagram of the method for forming an electromagnetic shield according to this embodiment.

[0029] The inkjet head 400 shown in Figure 3 was positioned to eject ink 500 in the direction normal to the upper surface 102 of the substrate 100, but the inkjet head 400 shown in Figure 4 is positioned to eject ink 500 in a direction intersecting the upper surface 102 and the side surface 104 of the substrate 100.

[0030] As shown in Figure 4(a), the inkjet head 400 applies ink 500 to the upper surface 102 of the substrate 100 placed on the mounting table 600, thereby forming the upper surface shield layer 250.

[0031] Next, the mounting platform 600 is moved in the direction of the arrow in the figure. This is an example of a movement process in which the object and the application unit are moved relative to each other in a direction intersecting the direction in which the application unit applies the liquid composition. The above is the same as in Figure 3.

[0032] Next, as shown in Figure 4(b), the inkjet head 400 applies ink 500 to the corners 106 and sides 104 of the substrate 100 placed on the mounting table 600, thereby forming a side shield layer 260.

[0033] Here, the direction in which the inkjet head 400 ejects the ink 500 is the same in Figures 4(a) and 4(b).

[0034] Then, by rotating the mounting base 600 around the vertical axis in the diagram, the inkjet head 400 applies ink 500 to the other three sides 104 of the substrate 100 placed on the mounting base 600, thereby forming the shield layer 260 on the other three sides.

[0035] As shown in Figures 3 and 4, in this embodiment, by simply moving the mounting table 600 in the horizontal direction of the figure or rotating the mounting table 600 around the vertical axis of the figure, a single inkjet head 400 can form a shield layer 200 on five surfaces of the substrate 100: the top surface, left and right sides, and front and rear sides.

[0036] In other words, compared to rotating the substrate 100 so that the side surface 104 of the substrate 100 faces upward, or providing separate inkjet heads 400 for each of the five surfaces of the substrate 100 (top surface, left and right sides, and front and rear sides), or changing the orientation of the inkjet heads 400, this embodiment allows for efficient formation of the shield layer 200.

[0037] Furthermore, when the inkjet head 400 is positioned as shown in Figure 4, the ink 500 can be ejected facing the side surface 104 of the substrate 100, thus ensuring the formation of a side shield layer 260 on the side surface 104 of the substrate 100.

[0038] Here, as shown in Figures 3 and 4, the thickness of the upper shield layer 250 is almost uniform, but the shield layer 260 on the side 104 is formed by the dripping of ink 500, so the lower part is thicker than the upper part.

[0039] In other words, the shield layer 260 is formed such that the difference between the thickness of the shield layer 260 at one end of the side surface 104, which is an example of a first surface, and the thickness of the shield layer 260 at the other end of the side surface 104 opposite to that end is greater than the difference between the thickness of the shield layer 250 at one end of the top surface 102, which is an example of a second surface, and the thickness of the shield layer 250 at the other end of the top surface 102 opposite to that end.

[0040] Figure 5 is an explanatory diagram illustrating the process of forming the electromagnetic shield according to this embodiment. Figure 5(a) is a side view of the substrate 100, and Figure 5(b) is a cross-sectional view AA in Figure 5(a).

[0041] As shown in Figures 5(a) and (b), an insulating material 510 is applied to the lower end of the side surface 104 of the substrate 100, and a conductive material 520 ejected by the inkjet head is dripped from above the side surface 104. The insulating material 510 is preferably applied by ejection by the inkjet head, but may be applied by other methods. The insulating material 510 is a thermosetting and photocurable resin and is an example of a protrusion formed on the surface of the side surface 104.

[0042] The insulating material 510 can be any material that has the same functionality as the ink 500 applied by the inkjet, such as Taiyo Ink IJSR-4000 or Go-O Chemical PR-1205.

[0043] Figure 6 is an explanatory diagram of the electromagnetic shield after formation according to this embodiment. Figure 6(a) is a side view of the substrate 100, and Figure 6(b) is a cross-sectional view AA in Figure 6(a).

[0044] As shown in Figures 6(a) and (b), the insulating material 510 applied to the lower end of the side surface 104 of the base material 100 blocks the conductive material 520 dripping from above. As a result, the conductive material 520 is formed so that the lower part is thicker than the upper part of the side surface 104.

[0045] The conductive material 520 is preferably the ink 500 applied by inkjet, such as GenesInk Smart Jet I (S-CS01520) Ag particles or Bando Chemical SR7000 Ag particles, but any conductive material having the same function as these inks is acceptable.

[0046] Here, the insulating material 510 is provided with a gap that allows the conductive material 520 to pass through, so that a portion of the conductive material 520 dripped from above reaches the ground portion 100G. Alternatively, the insulating material 510 may be provided so that it extends beyond the ground portion 100G.

[0047] As described above, in this embodiment, by applying insulating material 510 to the lower end of the side surface 104 of the base material 100, it is possible to suppress the leakage of conductive material 520 that has been dripped onto the side surface 104 before it hardens, and to reliably form a side shield layer 260 on the side surface 104 of the base material 100.

[0048] Figure 7 is another explanatory diagram showing the process of forming the electromagnetic shield according to this embodiment. Figure 7(a) is a side view of the substrate 100, and Figure 7(b) is a cross-sectional view AA in Figure 7(a).

[0049] As shown in Figures 7(a) and (b), an insulating material 510 is applied to the side surface 104 of the substrate 100, and the conductive material 520 ejected by the inkjet head is dripped from above the side surface 104.

[0050] Unlike in Figures 5 and 6, the insulating material 510 is applied to the base material 100 in addition to the lower end of the side surface 104, but it is applied in such a way that the density is higher at the bottom compared to the top of the side surface 104.

[0051] Figure 8 is another explanatory diagram showing the electromagnetic shield after formation according to this embodiment. Figure 8(a) is a side view of the substrate 100, and Figure 8(b) is a cross-sectional view AA in Figure 8(a).

[0052] As shown in Figures 8(a) and (b), the insulating material 510 applied to the side surface 104 of the base material 100 obstructs the flow of the conductive material 520 dripped from above, and the insulating material 510 applied to the lower end of the side surface 104 of the base material 100 blocks the flow of the conductive material 520 dripped from above.

[0053] As a result, the conductive material 520 is formed such that the lower part is thicker than the upper part of the side surface 104.

[0054] Here, as in Figures 5 and 6, the insulating material 510 is provided with a gap that allows the conductive material 520 to pass through, so that a portion of the conductive material 520 dripped from above reaches the ground portion 100G. Alternatively, the insulating material 510 may be provided so that it extends beyond the ground portion 100G.

[0055] As described above, in this embodiment, by applying insulating material 510 to the side surface 104 of the base material 100, the outflow of conductive material 520 that has dripped onto the side surface 104 is suppressed. Furthermore, by making the density higher at the lower part of the side surface 104 of the base material 100 compared to the upper part, and by applying insulating material 510 to the lower end, the outflow of conductive material 520 that has dripped onto the side surface 104 is reliably suppressed. This ensures that a side shield layer 260 is reliably formed on the side surface 104 of the base material 100.

[0056] Furthermore, the shield layer 250 on the upper surface 102 of the base material 100 does not have to contain insulating material 510, as the conductive material 520 does not flow out as on the side surface 104. However, insulating material 510 may be included for reasons such as oxidation prevention. In that case, it is preferable that the density of insulating material 510 within the shield layer 250 be uniform.

[0057] Figure 9 is an explanatory diagram of the process for forming an electromagnetic shield according to this embodiment.

[0058] First, the substrate 100 is set as the workpiece in the inkjet device (step S1), and the workpiece is cleaned (step S2). In this example, air blow cleaning using air pressure was used for cleaning the workpiece, but general organic solvents (such as alcohols), adhesive roller cleaning, plasma cleaning, etc. may also be used.

[0059] Next, as explained in Figures 6 and 8, ink 500 containing insulating material 510 is applied to the side surface 104 of the substrate 100 placed on the mounting table 600 using the inkjet head 400 (step S3), and the insulating material 510 is cured by UV exposure (step S4).

[0060] In this example, IJSR4000IJ material manufactured by Taiyo Ink Manufacturing Co., Ltd. was used as the insulating material 510, and UV exposure was performed at a wavelength of 365 nm for 1 to 9 seconds.

[0061] By repeating steps S3 and S4, the thickness of the insulating material 510 can be increased to a desired thickness.

[0062] Next, the appearance and film thickness of the insulating material 510 are inspected (step S5), and the temperature of the mounting table 600 is raised to 30-200°C, preferably 130°C (step S6).

[0063] Then, as explained in Figures 3 and 4, ink 500 containing conductive material 520 is applied to the upper surface 102 and side surface 104 of the substrate 100 placed on the mounting table 600 by the inkjet head 400 (step S7), and the conductive material 520 is heat-cured (step S8).

[0064] In the example, ULVAC's Ag material was used as the conductive material 520, and the thermosetting was carried out at 150°C for 30 minutes.

[0065] Next, an appearance and film thickness inspection is performed on the conductive material 520 to check its coating position, film thickness, and other film conditions (Step S9).

[0066] Figure 10 is an explanatory diagram of an electromagnetic shield according to an embodiment of this model, and is a photograph showing the object whose coating state was observed in step S9 of Figure 9.

[0067] In the embodiment, the thickness of the insulating material 510 was generally thin, so the conductive material 520 was generally coated on the surface of the side surface 260 of the shield layer. Near the boundary between the side surface 104 of the substrate 100 and the ground portion 100G, the insulating material 510 created irregularities, and the conductive material 520 was blocked in this area.

[0068] These results confirm that by optimizing the thickness of the insulating material 510 and the surface energy and discharge rate of the conductive material 520, it is possible to form a shield layer 200 on the side surface 104 of the substrate 100.

[0069] Furthermore, these results confirm that conductive material 520 can be applied to workpieces even when they have an uneven surface.

[0070] ●Summary● As described above, a method for forming a shield layer 200 according to one embodiment of the present invention includes a first application step of applying ink 500 containing a conductive material 520 to the upper surface 102 of a substrate 100 using an inkjet head 400, and a second application step of applying ink 500 to the side surface 104 of the substrate 100 using an inkjet head 400. Preferably, between the first application step and the second application step, a moving step is included in which the substrate 100 and the inkjet head 400 are moved relative to each other in a direction intersecting the direction in which the inkjet head 400 applies the ink 500.

[0071] Here, the substrate 100 is an example of an object, the shield layer is an example of a conductive layer, the inkjet head 400 is an example of an ink application unit, and the ink 500 is an example of a liquid composition.

[0072] This allows for the efficient formation of shield layers 250 and 260 on the upper surface 102 and side surface 104 of the substrate 100.

[0073] In the second application step, the inkjet head 400 applies ink in a direction intersecting the upper surface 102 and side surface 104 of the substrate 100. This allows the ink 500 to be ejected opposite the side surface 104 of the substrate 100, thereby ensuring the formation of a shield layer 260 on the side surface 104 of the substrate 100.

[0074] In the second application step, the direction in which the inkjet head 400 applies ink to the side surface 104 is the same as the direction in which the inkjet head 400 applies ink to the top surface 102 in the first application step.

[0075] This allows for more efficient formation of the shield layers 250 and 260 compared to changing the orientation of the inkjet head 400.

[0076] As a result of the above formation method, the shield layer 260 formed on the side surface 104 is configured to be thicker at the bottom than at the top.

[0077] The shield layer 260 formed on the side surface 104 includes an insulating material 510. This prevents the conductive material 520 dropped onto the side surface 104 from flowing out before it hardens, ensuring the formation of a shield layer 260 on the side surface 104. The insulating material 510 is an example of a protrusion formed on the surface of the side surface 104 and a photocurable resin.

[0078] In the shield layer 260 formed on the side surface 104, the insulating material 510 has a higher density at the bottom compared to the top. This reliably prevents the conductive material 520 dripped onto the side surface 104 from flowing out before it hardens, and allows for a more reliable formation of the shield layer 260 on the side surface 104.

[0079] The method for forming the shield layer 200 includes a third application step, prior to the first application step, in which ink 500 containing an insulating material 510 is applied to the side surface 104 by an inkjet head 400.

[0080] This allows the insulating material 510 to be applied to the side surface 104 before the inkjet head 400 applies the ink 500 containing the conductive material 520.

[0081] The shield layer 200 according to one embodiment of the present invention is a shield layer 200 formed on an upper surface 102, which is an example of a first surface that intersects with the substrate 100, and a side surface 104, which is an example of a second surface, wherein the difference between the thickness of the shield layer 260 at one end of the side surface 104 and the thickness of the shield layer 260 at the other end of the side surface 104 is greater than the difference between the thickness of the shield layer 250 at one end of the upper surface 102 and the thickness of the shield layer 250 at the other end of the upper surface 102 opposite to the one end. This makes it possible to obtain an efficiently formed shield layer 200.

[0082] Furthermore, the shield layer 200 according to one embodiment of the present invention is a shield layer 200 formed on a side surface 104, which is an example of the surface of the substrate 100, wherein the thickness of the shield layer 260 at one end of the side surface 104 is greater than the thickness of the shield layer 260 at the other end opposite to the side surface 104, and the density of the insulating material 510 contained in the shield layer 260 at one end of the side surface 104 is greater than the density of the insulating material 510 contained in the shield layer 260 at the other end opposite to the side surface 104. This makes it possible to obtain a shield layer 200 that is formed efficiently and reliably. [Explanation of symbols]

[0083] 1 Electronic equipment 100 Base material 102 Top surface 104 Side view 106 corners 100G Ground Section 110 Semiconductor Packages 120 Electronic Components 125 Connection part 130 circuit boards 135 Wiring 200 Shielding layer (an example of a conductive layer) 250 Top 260 Side view 300 protective layer 400 Inkjet head (Example of application part) 500 Ink (an example of a liquid composition) 510 Insulating material 520 Conductive material 600 mounting platform

Claims

1. A method for forming a conductive layer using a liquid composition containing a conductive material, A first application step involves applying the liquid composition to the upper surface of the object using an application unit, A second application step involves applying the liquid composition to the side surface of the object using the application unit, Includes, In the second application step, the application unit applies the liquid composition to the side surface on which a plurality of protrusions are formed on the surface. The aforementioned protrusion is a method for forming a conductive layer in which the density of the lower part is higher than that of the upper part in the conductive layer formed on the side surface.

2. A first application step involves applying a liquid composition containing a conductive material to the upper surface of the object using an application unit, A second application step involves applying the liquid composition to the side surface of the object using the application unit, Includes, In the second application step, the application unit applies the liquid composition to the side surface on which a plurality of protrusions are formed on the surface. Prior to the first application step, A method for forming a conductive layer, comprising a third application step of applying a liquid composition to the side surface using an application unit to form the plurality of protrusions.

3. Between the first application step and the second application step, a moving step is provided in which the object and the application unit are moved relative to each other in a direction intersecting the direction in which the application unit applies the liquid composition, A method for forming a conductive layer according to claim 1 or 2, further comprising:

4. In the second application step, The method for forming a conductive layer according to any one of claims 1 to 3, wherein the application portion applies the liquid composition in a direction intersecting the upper surface and the side surface of the object.

5. A method for forming a conductive layer according to any one of claims 1 to 4, wherein in the second application step, the direction in which the application unit applies the liquid composition to the side surface is the same as the direction in which the application unit applies the liquid composition to the upper surface in the first application step.

6. The method for forming a conductive layer according to any one of claims 1 to 5, wherein the conductive layer formed on the side surface has a greater thickness at the bottom than at the top.

7. The method for forming a conductive layer according to any one of claims 1 to 6, wherein the aforementioned protrusions are formed by a curable resin.

8. The method for forming a conductive layer according to claim 7, wherein the curable resin is cured by light.

9. The method for forming a conductive layer according to any one of claims 1 to 8, wherein the plurality of protrusions are formed of an insulating material.

10. Prior to the first application step, A method for forming a conductive layer according to claim 1, comprising a third application step of applying a liquid composition to the side surface using an application unit to form the plurality of protrusions.

11. A conductive layer formed on the surface of an object, The thickness of the conductive layer at one end of the surface is greater than the thickness of the conductive layer at the other end of the surface opposite to the one end. A conductive layer in which the density of the curable resin contained in the conductive layer at one end of the surface is greater than the density of the curable resin contained in the conductive layer at the other end of the surface opposite to the one end.

12. An electronic module comprising the conductive layer according to claim 11.

13. An electronic device comprising the conductive layer according to claim 11, or the electronic module according to claim 12.

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