Patent ID: 12211811

DESCRIPTION OF THE EMBODIMENTS

The present disclosure will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. The terms used herein such as “on”, “above”, “below”, “front”, “back”, “left” and “right” are for the purpose of describing directions in the figures only and are not intended to be limiting of the disclosure. Moreover, in the following embodiments, the same or similar reference numbers denote the same or like components.

The present disclosure is directed to an electronic device and a method for manufacturing the electronic device, which can reduce the stress difference on the bonding surface when the electronic component is disposed on a non-planar substrate.

FIG.1is a schematic cross-sectional view of an electronic device according to an embodiment of the disclosure.FIG.2is a schematic diagram of a manufacturing process of an electronic device according to an embodiment of the disclosure. Referring to bothFIG.1andFIG.2, in the present embodiment, the electronic device100may include a substrate110, an electronic component120, a first conductive interposing layer130, and a second conductive interposing layer140as shown inFIG.1. The manufacturing method of the electronic device100of this embodiment may include the following steps. In one embodiment, step S110is performed to provide a substrate110. In some embodiments, the substrate110may include an insulating substrate and a conductive material disposed on the insulating substrate, wherein, the insulating substrate of the substrate110may include polyethylene terephthalate (PET), poly (ethylene terephthalateco-1, 4-cylclohexylenedimethylene terephthalate) (PETG), polycarbonate (PC), polyimide (PI), poly(methyl methacrylate) (PMMA), Polyethersulfone (PES), polydimethylsiloxane (PDMS), acrylic, any combination thereof or other suitable insulating substrates. In an embodiment, the substrate110may be formed by, for example, in-mold electronic (IME) technology. In-mold electronic technology can embed electronic components in injection molding devices, or the like, to form a double-sided molded component by molding two layers of film, one side is used for decoration, while film circuit is molded to the other side. Molding resin is usually injected between the two films. In this structure, the circuit including printed sensors, resistors, and other required components can form a fully functional independent component (circuit substrate) with an insulating substrate, and sealed with a molded resin. With this method, the substrate110can be easily formed into a polygonal (for example, a triangle, a rectangle, or a pentagon), an arc, a circle, or a structure with a shape that has at least one curved edge.

In some embodiments, the substrate110is a non-planar substrate. In the present embodiment, the substrate110is a curvy substrate. In other words, the substrate110includes a substrate bonding surface112for bonding with the electronic component120, and the substrate bonding surface112is non-planar. In one embodiment, the curvature of the substrate bonding surface112is not zero, that is, the substrate bonding surface112is a curvy surface. In the present embodiment, the substrate110includes a plurality of substrate pads, where the substrate pad includes a first substrate pad114and a second substrate pad116. Certainly, this disclosure does not limit the number of substrate pads on the substrate bonding surface112. In an embodiment, the materials of the first substrate pad114and the second substrate pad116may include gold, silver, copper, aluminium, nickel, tin, alloys thereof, or any combination thereof. In the present embodiment, the material of the first substrate pad114and the second substrate pad116may be silver, but it is not limited thereto. In one embodiment, the radius of curvature R1of the substrate110is substantially from about 20 mm to about 100 mm, the thickness of the substrate110is substantially from about 0.1 mm to about 5 mm. In addition, the Young's modulus of the substrate110can be substantially from about 0.5 GPa to about 20 GPa. Certainly, this disclosure is not limited thereto.

In one embodiment, step S120is performed to provide an electronic component120, where the electronic component120can be a light-emitting diode, a chip, or various other electronic component120suitable for being disposed on the substrate110. In the present embodiment, the electronic component120may include a component bonding surface122for bonding with the substrate110and a plurality of component pads. In one embodiment, a plurality of component pads may be disposed on the component bonding surface122. The component pads include a first component pad124and a second component pad126. In addition, the first component pad124and the second component pad126face and correspond to the first substrate pad114and the second substrate pad116respectively, so as to form an electrical connection with the first substrate pad114and the second substrate pad116when the electronic component120is disposed on the substrate110. Certainly, the present disclosure does not limit the number of component pads on the component bonding surface122. In an embodiment, the materials of the first component pad124and the second component pad126may include gold, silver, copper, aluminium, nickel, tin, alloys thereof, or any combination thereof. In the present embodiment, the component bonding surface122of the electronic component120is a planar surface. That is, the curvature of the component bonding surface122is about zero. In other words, in the present embodiment, the electronic component120having the substantially planar component bonding surface122is disposed on the substrate110that is non-planar, e.g., curvy. Therefore, the bonding surface between the electronic component120and the substrate110to be bonded is not conformal and has a height difference, e.g., height difference Δh as shown inFIG.3.

FIG.3is a schematic cross-sectional view of an electronic device in intermediate stages of the manufacturing process according to an embodiment of the disclosure. Referring toFIG.1toFIG.3, step S130is then performed, the height difference Δh between the second component pad126and the second substrate pad116when the first component pad124contacts the first substrate pad114is obtained according to the radius of curvature R1of the substrate110or the length L1of the electronic component120. In detail, in the present embodiment, since the bonding surfaces between electronic component120and substrate110are not conformal, e.g., the substrate bonding surface112being a curvy surface, while the component bonding surface122being a planar surface, there is a height difference Δh between the second component pad126and the second substrate pad116when the first component pad124contacts the first substrate pad114. The height difference Δh is the distance between the second component pad126and the second substrate pad116in a normal direction of the primary surface1261of the second component pad126. This height difference Δh would cause a greater difference, e.g., stress difference, between the bonding surface stress of the first substrate pad114and the first component pad124and the bonding surface stress of the second substrate pad116and the second component pad126when a pick and place device is utilized to apply pressure for disposing (pressing) the electronic component120onto the substrate110. As such, the electrical connection and electrical performance between the substrate110and the electronic component120may be poor, and the electronic component120may even be damaged, such as deformation or cracking.

FIG.4is a schematic diagram of electronic components with different lengths disposed on a substrate according to an embodiment of the disclosure. Referring toFIG.4, in the present embodiment, the first component pad124and the second component pad126may be two of the plurality of component pads that are farthest apart in the lengthwise direction. Therefore, the height difference Δh between the second component pad126and the second substrate pad116can be seen as the greatest height difference among the component pads and the substrate pads. Therefore, in order to control the stress difference between the electronic component120and the substrate110, the height difference Δh between the second component pad126and the second substrate pad116needs to be firstly calculated, the height difference Δh is associated with the radius of curvature R1of the substrate110or the length L1of the electronic component120. In the present embodiment, the relation between the radius of curvature R1/length L1of the electronic component120and the height difference Δh of the pads116and126can be analysed based on big data and multivariate regression analysis methods.

In detail, the height difference Δh between the second component pad126and the second substrate pad116can be taken as the dependent variable, the radius of curvature R1of the substrate110and the length L1of the corresponding electronic component120can be taken as the argument to build a multivariate regression model, e.g., relation (formula). Then, based on the big data of multiple experiments, e.g., multiple substrates having different radiuses of curvature and/or multiple electronic components having different lengths, the coefficients, such as fixed coefficients and weight coefficients, in the multivariate regression model are calculated. Then, the calculated coefficient is substituted into the multivariate regression model to obtain a correction model of the height difference Δh between the pads126and116. In this way, the actual radius of curvature R1of the substrate110and/or the actual length L1of the electronic component120can be substituted into the relation (formula) to obtain a estimated height difference Δh.

FIG.5is a schematic diagram of the relationship between the radius of curvature of the substrate of an electronic device and the height difference of the pads according to an embodiment of the present disclosure. Please refer toFIG.3andFIG.5, for example, in the present embodiment, under the condition that the electronic component120has a specific (same) length L1, the height difference Δh between second component pad126and second substrate pad116is taken as the dependent variable, and the different radiuses of curvature of substrate110are taken as the arguments to build a multivariate regression model. Then, based on the big data of multiple experiments, e.g., multiple substrates having different radiuses of curvature, the coefficients, such as fixed coefficient and weight coefficient, etc., in the multivariate regression model are calculated, so as to obtain the relation between different radiuses of curvature of the substrate110and the height difference Δh. In the present embodiment, the relation (formula) between the radius of curvature R1of the substrate110and the height difference Δh of the pads116and126is as follows:
y=1E−0.6x2−0.0006x+0.0694

Wherein y represents the height difference Δh between the second component pad126and the second substrate pad116, and x represents the radius of curvature of the substrate110.

Accordingly, a correction model, illustrated as a dashed line inFIG.5, of the height difference Δh between the second component pad126and the second substrate pad116can be obtained. Then, the radius of curvature R1of the substrate110is substituted into the relation to obtain the estimated height difference Δh between the second component pad126and the second substrate pad116.

FIG.6is a schematic diagram of the relationship between the length of the electronic component of an electronic device and the height difference of the pads according to an embodiment of the disclosure. Referring toFIG.4andFIG.6, in another embodiment, under the condition that the substrate110has a specific (same) curvature R1, the height difference Δh between the second component pad126and the second substrate pad116is taken as the dependent variable, and the different lengths, such as lengths L1, L2, L3, of the electronic component120are taken as the argument to build a multivariate regression model. Then, based on the big data of multiple tests, e.g., multiple electronic components120having different lengths, the coefficients, such as fixed coefficients and weight coefficients, in the multivariate regression model are calculated, so as to obtain the relation between the different lengths and the height difference Δh of the electronic component120. In the present embodiment, the relation between the different lengths of the electronic component120and the height difference Δh of the pads116and126is as follows:
y=0.063x2−0.1065x+0.0692

Wherein y represents the height difference Δh between the second component pad126and the second substrate pad116, and x represents the length of the electronic component120.

Accordingly, a correction model, illustrated as a dashed line inFIG.6, of the height difference Δh between the second component pad126and the second substrate pad116can be obtained. Then, the length L1of the electronic component120is substituted into the relation to obtain the estimated height difference Δh between the second component pad126and the second substrate pad116.

FIG.7toFIG.10are schematic diagrams of the relationship between the length of the electronic component and the height difference of the pad under the conditions that the substrate has different radius of curvature in an electronic device according to an embodiment of the present disclosure. In another embodiment,FIG.7toFIG.10respectively show that the substrate110is in different radiuses of curvature. For example, the radius of curvature of the substrate110inFIG.7is 20 mm, the radius of curvature of the substrate110inFIG.8is 40 mm, the radius of curvature of the substrate110inFIG.9is 60 mm, and the radius of curvature of substrate110inFIG.10is 80 mm, the height difference Δh between the second component pad126and the second substrate pad116is taken as the dependent variable, and the different lengths of the electronic component120is taken as the argument to build a multivariate regression model. Then, based on the big data of multiple experiments, e.g., multiple substrate110having different radiuses of curvature and multiple electronic component120having different lengths, the coefficients, such as fixed coefficient and weight coefficient, etc., in the multivariate regression model are calculated, so as to obtain the relations between the length of the electronic component120and the height difference Δh of the pads116and126under the conditions that the substrate110is in different radiuses of curvature.

In the embodiment ofFIG.7, under the condition that the radius of curvature of the substrate110is 20 mm, the relation between the different lengths of the electronic component120and the height difference Δh of the pads116and126is as follows:
y=0.063x2−0.1065x+0.0692

Wherein y represents the height difference Δh between the second component pad126and the second substrate pad116, and x represents the length of the electronic component120.

In the embodiment ofFIG.8, under the condition that the radius of curvature of the substrate110is 40 mm, the relation between the different lengths of the electronic component120and the height difference Δh of the pads116and126is as follows:
y=0.0406x2−0.1213x+0.1301

Wherein y represents the height difference Δh between the second component pad126and the second substrate pad116, and x represents the length of the electronic component120.

In the embodiment ofFIG.9, under the condition that the radius of curvature of the substrate110is 60 mm, the relation between the different lengths of the electronic component120and the height difference Δh of the pads116and126is as follows:
y=0.0224x2−0.043x+0.0465

Wherein y represents the height difference Δh between the second component pad126and the second substrate pad116, and x represents the length of the electronic component120.

In the embodiment ofFIG.10, under the condition that the radius of curvature of the substrate110is 80 mm, the relation between the different lengths of the electronic component120and the height difference Δh of the pads116and126is as follows:
y=0.0219x2−0.0447x+0.0454

Wherein y represents the height difference Δh between the second component pad126and the second substrate pad116, and x represents the length of the electronic component120.

After that, the radius of curvature R1of the substrate110and the length L1of the electronic component120are substituted into the corresponding relation that meets the conditions, and the estimated height difference Δh between the second component pad126and the second substrate pad116can be obtained.

Referring now back toFIG.1andFIG.2, after the height difference Δh between the pads116and126is obtained by using multivariate regression analysis according to the method described above. The conductive interposing layers130and140disposed between the substrate pads114and116and the component pads124and126can be used to compensate the height difference Δh between the pads116and126. To be more specific, step S140is then performed to dispose the first conductive interposing layer130on the first substrate pad114or the first component pad124, and dispose the second conductive interposing layer140on the second substrate pad116or the second component pad126. In addition, the thickness T2of the second conductive interposing layer140is designated to be substantially greater than the thickness T1of the first conductive interposing layer130, so as to utilize the second conductive interposing layer140with greater thickness T2to compensate the height difference Δh between the pads116and126. In one embodiment, the materials of the first conductive interposing layer130and the second conductive interposing layer140may include gold, silver, copper, aluminium, nickel, tin, alloys thereof, or any combination thereof. In another embodiment, the materials of the first conductive interposing layer130and the second conductive interposing layer140may include PEDOT, graphene, indium tin oxide (ITO), or any combination thereof. In one embodiment, the method of disposing the first conductive interposing layer130and the second conductive interposing layer140includes (gel) dispensing. Certainly, this disclosure is not limited thereto.

Through the stress simulations in big data analytics, it is known that, when the thickness difference (T2−T1) between the first conductive interposing layer130and the second conductive interposing layer140is from 0.5 to 1 times the height difference Δh, the difference in bonding surface stress between the pads is less than about 10%, which meets the requirements of product yield. Therefore, in the present embodiment, the thickness difference (T2−T1) between the first conductive interposing layer130and the second conductive interposing layer140is designed to be between 0.5 and 1 times the height difference Δh. With this configuration, there is a first bonding surface stress between the first substrate pad114and the first component pad124, there is a second bonding surface stress between the second substrate pad116and the second component pad126, and the difference between the first bonding surface stress and the second bonding surface stress is less than about 10%. For example, the thickness difference (T2−T1) between the first conductive interposing layer130and the second conductive interposing layer140can be designed to be about ⅔ times the height difference Δh. It is found through stress simulation analysis that such configuration not only makes the difference between the first bonding surface stress and the second bonding surface stress less than about 10%, but the actual values (readings) of the first bonding surface stress and the second bonding surface stress are also significantly reduced.

Accordingly, taking the embodiment ofFIG.5as an example, when the curvy substrate110is in convex warpage, the data obtained through the steps described above is shown in Table 1 below:

TABLE 1L1(mm)R1(mm)(0.5~1)Δh(mm)2/3Δh(mm)relation1.6 × 0.8200.06~0.030.04y =400.05~0.0250.031E−06x2−600.04~0.020.020.0006x + 0.0694800.028~0.0140.011000.019~0.00950.01

In another embodiment, when the curvy substrate110is in concave warpage, the data obtained through the steps described above is shown in Table 2 below:

TABLE 2radius ofcurvatureSize(mm)(mm)(0.5~1)Δh(mm)2/3Δh(mm)relation1.6 × 0.8200.06~0.030.04y =400.05~0.0250.03−1E−06x2−600.04~0.020.020.0006x + 0.0694800.028~0.0140.011000.019~0.00950.01

Herein, the data in the first column represents the size of electronic component120; the data in the second column represents the radius of curvature of substrate110; the data in the third column represents the range of the thickness difference (T2−T1), i.e., 0.5Δh to 1Δh, between the first conductive interposing layer130and the second conductive interposing layer140; the data in the fourth column represents the selected thickness difference (T2−T1), i.e., ⅔Δh, between the first conductive interposing layer130and the second conductive interposing layer140, the fifth column represents the relation between the radius of curvature of the substrate110and the height difference Δh between the pads116and126.

FIG.11is a schematic diagram of the stress distribution of an electronic device under pressure according to an embodiment of the disclosure. Referring toFIG.1andFIG.11, the step S150is then performed, wherein the electronic component120is disposed on the substrate110so that the first component pad124and the second component pad126are connected to the first substrate pad114and the second substrate pad116through the first conductive interposing layer130and the second conductive interposing layer140respectively. In the present embodiment, the electronic component120can be picked up and placed on the substrate110by, for example, a pick and place device, and a pressure is applied to the electronic component120through the nozzle of the device, so that the electronic component120is pressed against the substrate110. The first conductive interposing layer130and the second conductive interposing layer140with different thicknesses, for example, the thickness difference (T2−T1) being ⅔Δh, are used to compensate the height difference Δh between the pads116and126, such that the difference between the first bonding surface stress between the first substrate pad114and the first component pad124and the second bonding surface stress between the second substrate pad116and the second component pad126is less than about 10%.

For example,FIG.11is a schematic diagram of stress simulation analysis of an embodiment in which the radius of curvature R1of the substrate110in Table 1 is 40 mm, it can be seen fromFIG.11that, after the electronic component120and the substrate110are pressed together, the first bonding surface stress between the first substrate pad114and the first component pad124is about 11.129 MPa, the second bonding surface stress between the second substrate pad116and the second component pad126is about 12.613 MPa. It is shown that the difference between the first bonding surface stress and the second bonding surface stress is indeed less than 10%. Therefore, the electronic device100of the embodiment in the present disclosure can effectively improve the electrical performance and the yield of electrical connection between the electronic component120and the substrate110, and can further improve the reliability of the electronic device100.

FIG.12is a schematic diagram of the height of arc and thickness of a substrate of an electronic device according to an embodiment of the disclosure. As in the previous embodiments, the thickness of the substrate is from 0.1 mm to 5 mm, and the Young's modulus of the substrate is from 0.5 GPa to 20 GPa. Referring toFIG.12, in some embodiments, the substrate110may also be specially designed to further reduce the bonding surface stress between the electronic component120and the substrate110. To be more specific, the bonding surface stress between the electronic component120and the substrate110can be adjusted by controlling the ratio of the thickness T3of the substrate110to the height of arc Ah of the substrate110. Generally speaking, height of arc Δh refers to the vertical distance between the main spring coil and the center of the coil. In the curvy substrate110, the height of arc Ah of the substrate110at a certain location can represent the degree of curvature and convexity/concavity of the substrate110at that location.

For example, Table 3 below lists the values of the bonding surface stress between the electronic component120and the substrate110under the conditions of the electronic device being in different thicknesses and different heights of arc Ah.

TABLE 3substrate heightsubstratethickness/Stressof arc (mm)thickness (mm)height of arc(MPa)200.0180.000915.52300.020.0006615.75400.030.0007515.66500.040.000815.617600.050.0008315.5886700.060.0008615.5618020.0253

It is shown in Table 3 that, when the ratio of the thickness T3of the substrate110to the height of arc Ah of the substrate110is about equal to 0.025, the bonding surface stress between the electronic component120and the substrate110is significantly reduced to 3 MPa. Therefore, in the present embodiment, the electronic device can be designed as the ratio of the thickness T3of the substrate110to the height of arc Ah of the substrate110being greater than or substantially equal to 0.025, so as to reduce the bonding surface stress between the electronic component120and the substrate110to an acceptable range.

In summary, in the electronic device and the manufacturing method thereof in the disclosed embodiment, the electronic component is disposed on a non-planar substrate, and utilize the thickness difference between the conductive interposing layer between the substrate pad and the component pad to compensate for the height difference between the substrate pad and the component pad, so as to reduce difference of the bonding surface stress between the electronic component and the substrate. The height difference between the substrate pad and the component pad can be obtained according to the radius of curvature of the substrate or the length of the electronic component, and the thickness difference between the corresponding conductive interposing layers is substantially from 0.5 to 1 times the height difference. With such configuration, the difference between the bonding surface stresses of the electronic component and the substrate can be less than about 10%, which can effectively improve the electrical performance and the yield of electrical connection between the electronic component and the substrate, and also improve the reliability of the electronic device.

It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present disclosure without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the present disclosure cover modifications and variations of this disclosure provided they fall within the scope of the following claims and their equivalents.