Patent ID: 12249560

MODE FOR CARRYING OUT THE INVENTION

Electronic devices according to preferred embodiments of the present disclosure will be described below with reference to the drawings. Constituent elements that are the same or similar are given the same reference numerals, and a redundant description will be omitted.

FIGS.1to7show an electronic device according to a first embodiment. An electronic device A1according to the first embodiment includes an electronic component1, a lead frame2, a bonding material3, connecting members4, and a resin member5.

FIG.1is a plan view of the electronic device A1in which the resin member5is indicated by an imaginary line (a dashed-and-double-dotted line).FIG.2is a diagram corresponding to the plan view ofFIG.1in which an illustration of the connecting members4is omitted, and the electronic component1is indicated by an imaginary line.FIG.3is a bottom view of the electronic device A1.FIG.4is a side view (right side view) of the electronic device A1.FIG.5is a cross-sectional view taken along the line V-V shown inFIG.1.FIG.6is a partially enlarged cross-sectional view of a region VI shown inFIG.5.FIG.7is a partially enlarged cross-sectional view of a region VII shown inFIG.5.

For the sake of convenience of the description, inFIGS.1to7, three directions that are orthogonal to each other are defined as x direction, y direction, and z direction. The z direction is the thickness direction of the electronic device A1. The x direction is the left-right direction of the plan view of the electronic device A1(seeFIG.1). The y direction is the up-down direction of the plan view of the electronic device A1(seeFIG.1). In the description given below, one side in the z direction (the upper side of the cross-sectional view shown inFIG.5) may be referred to as “upper side”, and the other side in the z direction (the lower side of the cross-sectional view shown inFIG.5) may be referred to as “lower side”, but it is not intended to limit the orientation of the electronic device A1. The z direction corresponds to “first direction” recited in the appended claims.

The electronic device A1is a surface mount packaged electronic device. As shown inFIGS.1to7, the electronic device A1is configured in a package in which lead wires (terminal lead portions23, which will be described later) do not protrude from the resin member5as viewed in a plan view.

The electronic component1serves as the functional center of the electronic device A1. The electronic component1is, for example, an integrated circuit (IC) such as an LSI (Large Scale Integration). The electronic component1is not limited to an IC, and may be a voltage controlling element such as a LDO (Low Drop Out), an amplifying element such as an operational amplifier, a discrete component such as a transistor, a diode, an LED, or a terahertz element, or the like. Alternatively, the electronic component1may be, for example, a resistor, an inductor, a capacitor, or the like.

The electronic component1has, for example, a rectangular shape as viewed in a plan view. The electronic component1is bonded to a portion of the lead frame2(a die pad portion21, which will be described later) by using the bonding material3. As shown inFIGS.4and5, the electronic component1includes an obverse surface11and a reverse surface12.

The obverse surface11and the reverse surface12are spaced apart from each other in the z direction. The obverse surface11serves as an upper surface of the electronic component1, and the reverse surface12serves as a lower surface of the electronic component1. The obverse surface11and the reverse surface12are both flat.

The electronic component1includes a plurality of electrode pads13. The electrode pads13serve as terminals of the electronic component1. The electrode pads13are exposed from the obverse surface11.

The lead frame2is mounted on a circuit board such as an electronic device, and thereby serves as a conduction path between the electronic component1and the circuit board. The lead frame2supports the electronic component1. The lead frame2includes a conductive material. The conductive material is, for example, a metal that contains Cu (copper). Specifically, the lead frame2may be a metal plate made of Cu or a Cu alloy, or an organic substrate with a Cu layer formed on a surface thereof. The surface layer of the lead frame2is made of a metal that contains Cu. The lead frame2corresponds to “support member” recited in the appended claims. As shown inFIG.1, the lead frame2includes a die pad portion21, a plurality of hanging lead portions22, and a plurality of terminal lead portions23. In the electronic device A1, as shown inFIG.1, the lead frame2includes one die pad portion21, two hanging lead portions22, and eight terminal lead portions23.

As shown inFIGS.1and5, the electronic component1is mounted on the die pad portion21by being fixedly attached to the die pad portion21via the bonding material3. The die pad portion21has, for example, a rectangular shape as viewed in a plan view. As shown inFIG.5, the die pad portion21includes an obverse surface211and a reverse surface212.

The obverse surface211and the reverse surface212are spaced apart from each other in the z direction. The obverse surface211serves as an upper surface of the die pad portion21. The reverse surface212serves as a lower surface of the die pad portion21. As shown inFIGS.3to5, the reverse surface212is exposed from the resin member5. The reverse surface212may be covered with the resin member5. However, when the reverse surface212is exposed from the resin member5, the effect of dissipating heat from the electronic component1increases. As shown inFIG.2, the obverse surface211includes a first region211aand a second region211b. A detailed description of the first region211aand the second region211bwill be given later. The obverse surface211corresponds to “mount surface” recited in the appended claims.

As shown inFIGS.1and5, the plurality of hanging lead portions22are connected to the die pad portion21. As viewed in a plan view, the plurality of hanging lead portions22extend in the y direction from opposing end edges of the die pad portion21in the y direction. Each hanging lead portion22is partially bent in the z direction. In the example shown inFIG.5, an end edge of each hanging lead portion22that is connected to the die pad portion21in the y direction is positioned lower in the z direction than the other end edge of the hanging lead portion22that is on the opposite side, but it may be positioned higher in the z direction.

The plurality of terminal lead portions23are partially exposed from the resin member5and serve as external terminals of the electronic device A1. As shown inFIG.1, the terminal lead portions23are spaced apart from the die pad portion21and the hanging lead portions22. As shown inFIGS.1to4, each terminal lead portion23includes a pad portion231and a terminal portion232.

One end of a connecting member4is bonded to the pad portion231. The terminal portion232is partially exposed from the resin member5. In each terminal lead portion23, the pad portion231and the terminal portion232are connected to each other, and are unitarily formed as a single piece.

As shown inFIGS.4and5, the bonding material3is provided between the electronic component1and the die pad portion21(the lead frame2) to bond them. The material that constitutes the bonding material3contains a first composition in the form of a solid. The first composition is, for example, solder. The solder may be lead-free solder or lead-containing solder. The bonding material3may be a conductive bonding material other than solder. Alternatively, the bonding material3may be an insulating bonding material, instead of the conductive bonding material. The first composition is a material that undergoes a phase transition to a liquid by being heated.

As shown inFIG.5, the bonding material3includes a first surface31, a second surface32, and a third surface33. The first surface31faces upward in the z direction, and is in contact with the electronic component1. The second surface32faces downward in the z direction, and is in contact with the die pad portion21of the lead frame2. In the present embodiment, the second surface32substantially completely overlaps the first region211aas viewed in a plan view. The third surface33is connected to the first surface31and the second surface32. The third surface33is a curved surface. In the present embodiment, as shown inFIG.2, a portion of the third surface33(outer periphery as viewed in a plan view) overlaps the second region211bas viewed in a plan view. The third surface33does not necessarily need to overlap the second region211bas viewed in a plan view.

The plurality of connecting members4electrically connect the electronic component1and the lead frame2(the terminal lead portions23). The connecting members4are, for example, bonding wires. The connecting members4are not limited to bonding wires, and may be bonding ribbons or plate-like clip members. The material that constitutes the connecting members4may be any one of Cu, Au (gold), and Al (aluminum).

In each connecting member4, one end is bonded to one of the electrode pads13of the electronic component1, and the other end is bonded to the pad portion231of one of the terminal lead portions23. In the present embodiment, each connecting member4is a bonding wire, with one end being bonded to an electrode pad13through ball bonding and the other end being bonded to a pad portion231through wedge bonding. Alternatively, one end may be bonded to a pad portion231through ball bonding, and the other end may be bonded to an electrode pad13through wedge bonding.

The resin member5serves as a sealing material in the electronic device A1. As shown inFIGS.4and5, the resin member5covers the electronic component1, a portion of the lead frame2, the bonding material3, and the plurality of connecting members4. The material that constitutes the resin member5contains a second composition in the form of a solid. The second composition is, for example, an epoxy resin. The resin member5has, for example, a rectangular shape as viewed in a plan view. As shown inFIGS.1to5, the resin member5includes a resin obverse surface51, a resin reverse surface52, and a plurality of resin side surfaces53.

The resin obverse surface51and the resin reverse surface52are spaced apart from each other in the z direction. The resin obverse surface51serves as an upper surface of the resin member5. The resin reverse surface52serves as a lower surface of the resin member5. As shown inFIG.3, a portion of the lead frame2(a portion of the reverse surface212of the die pad portion21and the terminal portions232) is exposed from the resin reverse surface52. The plurality of resin side surfaces53are connected to both the resin obverse surface51and the resin reverse surface52, and are sandwiched between the resin obverse surface51and the resin reverse surface52in the z direction. The resin member5includes a pair of resin side surfaces531that are spaced apart from each other in the x direction and a pair of resin side surfaces532that are spaced apart from each other in the y direction. In the present embodiment, in the terminal portion232of each terminal lead portion23, a portion of the terminal portion232is exposed from the resin reverse surface52and is also exposed from one of the pair of resin side surfaces531.

Next, the first region211aand the second region211bincluded in the obverse surface211of the die pad portion21will be described.

As shown inFIG.5, the first region211ais in contact with the bonding material3. The first region211ahas, for example, a rectangular shape as viewed in a plan view. The electronic component1overlaps the first region211aas viewed in a plan view. As shown inFIG.6, the first region211aincludes a plurality of grooves711, a plurality of raised portions712, and a plurality of intervening portions713.

The plurality of grooves711are recessed toward the lower side in the z direction from the intervening portions713. The plurality of grooves711may be formed through, for example, laser processing in which laser light is applied thereto. The method for forming the plurality of grooves711is not limited to laser processing, and may be, for example, etching or the like. The plurality of grooves711are arranged in an arrangement pattern described below. The grooves711extend linearly in a direction perpendicular to the z direction. In the present embodiment, as shown inFIG.2, the grooves711extend in the x direction, but may extend in the y direction. The plurality of grooves711are arranged in parallel to each other. Each groove711has a width W1(seeFIG.6) of, for example, about 20 to 40 μm. Each groove711has a depth d1(seeFIG.6) of, for example, about 5 to 20 μm. A spacing P1between two adjacent grooves711(seeFIG.6) is, for example, about 30 to 200 μm. The spacing P1refers to the distance between the centers of two adjacent grooves711in the width direction.

As shown inFIG.6, the plurality of raised portions712are provided such that each raised portion712is connected to one of two end edges of one groove711in the y direction. One of two end edges of each raised portion712in the y direction is connected to one of the grooves711and the other end edge is connected to one of the intervening portions713. The raised portions712protrude toward the upper side in the z direction from the intervening portions713.

As shown inFIG.6, each of the plurality of intervening portions713is provided between two adjacent grooves711. Each intervening portion713is interposed between two adjacent grooves711in the y direction via the raised portions712. The intervening portions713are formed as a result of laser light being not applied during the formation of the grooves711. As shown inFIG.8, the intervening portions713may not be formed depending on the width W1and the spacing P1between the plurality of grooves711formed by laser processing. For example, if the spacing P1is smaller than the width W1of the grooves711, the intervening portions713are not formed. In this case, as shown inFIG.8, each raised portion712is provided between two adjacent grooves711, and both end edges of the raised portion712in the y direction are connected to the grooves711.

The first region211ais roughened due to the plurality of grooves711, the plurality of raised portions712, and the plurality of intervening portions713. Accordingly, the first region211ais a rough surface. Also, the surface of each of the plurality of grooves711and the surface of each of the plurality of raised portions712have fine irregularities that are formed through laser processing. Accordingly, the surface of each of the plurality of grooves711and the surface of each of the plurality of raised portions712are rough surfaces due to the fine irregularities. The surface of each of the plurality of grooves711and the surface of each of the plurality of raised portions712have a surface roughness finer than that of the first region211a.

The first region211ahas a lyophilicity for the first composition (for example, solder) in the form of a liquid. In the present embodiment, due to the plurality of grooves711formed in the first region211a, the first region211ahas a lyophilicity for the first composition in the form of a liquid. Also, the first region211awhere the plurality of grooves711are formed has a higher lyophilicity for the first composition in the form of a liquid than the first region211awhere the plurality of grooves711are not formed.

As shown inFIG.5, the second region211bis not in contact with the bonding material3, but is in contact with the resin member5. The second region211bhas, for example, a rectangular annular shape as viewed in a plan view. The second region211bsurrounds the first region211aas viewed in a plan view. The second region211bis configured such that an inner edge thereof is in contact with an outer edge of the first region211aas viewed in a plan view. As shown inFIG.7, the second region211bincludes a plurality of grooves721, a plurality of raised portions722, and a plurality of intervening portions723.

As shown inFIG.7, the plurality of grooves721are recessed toward the lower side in the z direction from the intervening portions723. The plurality of grooves721may be formed through, for example, laser processing. The method for forming the plurality of grooves721is not limited to laser processing, and may be, for example, etching or the like. The plurality of grooves721are arranged in an arrangement pattern described below. The grooves721extend linearly in a direction perpendicular to the z direction. In the present embodiment, as shown inFIG.2, the grooves721extend in the x direction, but may extend in the y direction. The plurality of grooves721are arranged in parallel to each other. Each groove721has a width W2(seeFIG.7) of, for example, about 5 to 10 μm. Each 721 has a depth d2(seeFIG.7) of, for example, about 5 to 10 μm. A spacing P2between two adjacent grooves721(seeFIG.7) is, for example, about 10 to 20 μm. The spacing P2refers to the distance between the centers of two adjacent grooves721in the width direction.

As shown inFIG.7, the plurality of raised portions722are provided such that each raised portion722is connected to one of two end edges of one groove721in the y direction. One of two end edges of each raised portion722in the y direction is connected to one of the grooves721and the other end edge is connected to one of the intervening portions723. The raised portions722protrude toward the upper side in the z direction from the intervening portions723.

As shown inFIG.7, each of the plurality of intervening portions723is provided between two adjacent grooves721. Each intervening portion723is interposed between two adjacent grooves721in the y direction via the raised portions722. The intervening portions723are formed as a result of laser light being not applied during the formation of the grooves721. As with the intervening portions713, the intervening portions723may not be formed (seeFIG.8) depending on the width W2and the spacing P2between the plurality of grooves721formed by laser processing. For example, if the spacing P2is smaller than the width W2of each groove721, the intervening portions723are not formed. In this case, each raised portion722is provided between two adjacent grooves721, and both end edges of the raised portion722in the y direction are connected to the grooves721.

The second region211bis roughened due to the plurality of grooves721, the plurality of raised portions722, and the plurality of intervening portions723. Accordingly, the second region211bis a rough surface. Also, the surface of each of the plurality of grooves721and the surface of each of the plurality of raised portions722have fine irregularities that are formed through laser processing. Accordingly, the surface of each of the plurality of grooves721and the surface of each of the plurality of raised portions722are rough surfaces due to the fine irregularities. The surface of each of the plurality of grooves721and the surface of each of the plurality of raised portions722have a surface roughness finer than that of the second region211b.

The second region211bhas a lyophilicity for the second composition (for example, an epoxy resin) in the form of a liquid. In the present embodiment, due to the plurality of grooves721formed in the second region211b, the second region211bhas a lyophilicity for the second composition in the form of a liquid.

In the obverse surface211of the die pad portion21, the first region211ahas a higher lyophilicity for the first composition in the form of a liquid than the second region211b. In the present embodiment, the first composition is solder, and thus the first region211ahas a solder wettability higher than that of the second region211b. For example, by adjusting the width W1, the spacing P1, and the depth d1of the grooves711formed in the first region211aand the width W2, the spacing P2, and the depth d2of the grooves721formed in the second region211b, a difference is generated between the lyophilicity for the first composition in the form of a liquid and the lyophilicity for the second composition in the form of a liquid. In the electronic device A1, for example, the width W1of the grooves711is adjusted to be larger than the width W2of the grooves721, and the spacing P1between grooves711is adjusted to be larger than the spacing P2between grooves721. In doing so, the lyophilicity of the first region211afor the first composition in the form of a liquid is higher than the lyophilicity of the second region211bfor the first composition in the form of a liquid.

A method for manufacturing the electronic device A1will be described next with reference toFIGS.9to13.FIGS.9to13are plan views illustrating the steps of a method for manufacturing the electronic device A1.

First, as shown inFIG.9, a lead frame2is prepared. This step corresponds to “first step” recited in the appended claims. The lead frame2to be prepared may be formed by, for example, punching or bending a copper plate. As shown inFIG.9, the lead frame2at this time includes a die pad portion21, a plurality of hanging lead portions22, a plurality of terminal lead portions23, and a plurality of tie bars25. The die pad portion21, the plurality of hanging lead portions22, and the plurality of terminal lead portions23are connected by the plurality of tie bars25.

Next, as shown inFIG.10, a first region211aand a second region211bare formed in the die pad portion21of the lead frame2. This step corresponds to “second step” recited in the appended claims. The first region211ais a region where a bonding material3is formed and an electronic component1is mounted. The second region211bis a region where the bonding material3is not formed. Specifically, laser light is applied to the obverse surface211of the die pad portion21of the lead frame2so as to excavate the obverse surface211and form a plurality of grooves711and a plurality of grooves721. The application of laser light is performed using a well-known laser application apparatus. The plurality of grooves711are formed in, for example, a rectangular region as viewed in a plan view. The region where the plurality of grooves711are formed is the first region211a. The plurality of grooves721are formed in a rectangular annular region as viewed in a plan view that surrounds the region (the first region211a) where the plurality of grooves711are formed. The region where the plurality of grooves721are formed is the second region211b. The arrangement pattern of the plurality of grooves711and the arrangement pattern of the plurality of grooves721have already been described above. The first region211aand the second region211bmay be formed in any order, and may be formed simultaneously. In the drawings (FIGS.11to13) that are to be referred to in the following description, an illustration of the grooves711and721is omitted.

Next, as shown inFIG.11, a bonding material3in the form of a paste is applied to the region (the first region211a) where the plurality of grooves711are formed, and an electronic component1is placed on the bonding material3in the form of a paste. The step of applying a bonding material3in the form of a paste corresponds to “third step” recited in the appended claims, and the step of placing an electronic component1on the bonding material3in the form of a paste corresponds to “fourth step” recited in the appended claims. The material that constitutes the bonding material3is a first composition. The first composition is, for example, solder. Accordingly, a solder paste is applied to the first region211a.

Next, reflow processing is performed. This step corresponds to “fifth step” recited in the appended claims. In the reflow processing, due to heat during the reflow processing, the bonding material3in the form of a paste turns into a liquid, and thus the flowability increases. The bonding material3in the form of a liquid spreads over the first region211a. This is because, due to the plurality of grooves711, the first region211ahas a lyophilicity for the bonding material3in the form of a liquid. At this time, the bonding material3in the form of a liquid spreads uniformly over the first region211adue to the lyophilicity of the first region211afor the bonding material3in the form of a liquid. Also, the bonding material3in the form of a liquid remains in the first region211a, and does not flow out to the second region211b. This is because the lyophilicity of the second region211bfor the bonding material3in the form of a liquid is lower than that of the first region211a, and thus a force that causes the bonding material3in the form of a liquid to remain in the first region211aacts, as a result of which, the likelihood of the bonding material3flowing to the second region211bis suppressed. After that, through cooling during the reflow processing, the bonding material3in the form of a liquid solidifies and turns into a solid. As a result, the electronic component1is bonded to the lead frame2(the die pad portion21) by the bonding material3in the form of a solid.

Next, as shown inFIG.12, electrode pads13provided in the obverse surface11of the electronic component1and pad portions231provided in the terminal lead portions23of the lead frame2are electrically connected using connecting members4. The connecting members4are, for example, bonding wires, and the connecting members4are formed by using, for example, a wire bonding apparatus that includes a capillary.

Next, as shown inFIG.13, a resin member5is formed. The resin member5is formed by, for example, transfer molding. The material that constitutes the resin member5contains a second composition in the form of a solid. The second composition is, for example, an epoxy resin.

Next, the lead frame2and the resin member5are cut to singulate individual electronic components1. For example, the individual electronic components1can be obtained by blade dicing.

An electronic device A1as shown inFIGS.1to7is formed through the steps described above. The manufacturing method described above is merely an example.

The electronic device A1configured as described above has the following advantageous effects.

In the electronic device A1, the electronic component1is fixedly attached to the lead frame2(the die pad portion21) by the bonding material3(solid). The lead frame2(the die pad portion21) includes the obverse surface211on which the electronic component1is mounted. The obverse surface211includes the first region211awhere the plurality of grooves711are formed and the second region211bthat surrounds the first region211aas viewed in a plan view. The bonding material3is in contact with the first region211a, and is not in contact with the second region211b. With this configuration, the bonding material3is not formed in the second region211bthat surrounds the first region211a, and thus the likelihood of the thickness of the bonding material3being thin or non-uniform in the first region211acan be suppressed. For example, if the bonding material3has a non-uniform thickness, the electronic component1will be fixedly attached in an inclined state, which causes a bonding failure of the electronic component1, a bonding failure of the connecting members4, and the like. On the other hand, in the electronic device A1, the likelihood of the thickness of the bonding material3being non-uniform can be suppressed, and thus the bonding failures described above can be suppressed. Accordingly, with the electronic device A1, the reliability can be improved.

In the electronic device A1, the bonding material3is the first composition (for example, solder) in the form of a solid, and the first region211ahas a higher lyophilicity for the first composition in the form of a liquid than that of the second region211b. With this configuration, when the bonding material3turns into a liquid during the process of manufacturing the electronic device A1(reflow processing), the bonding material3in the form of a liquid tends to remain in the first region211athat has a relatively high lyophilicity for the first composition in the form of a liquid, and it is therefore possible to prevent the bonding material3in the form of a liquid from spreading to the second region211bthat has a relatively low lyophilicity for the first composition in the form of a liquid. Accordingly, in the electronic device A1, as a result of the first region211ahaving a higher lyophilicity for the first composition in the form of a liquid than that of the second region211b, the likelihood of the bonding material3in the form of a liquid flowing to the second region211bcan be suppressed.

In the electronic device A1, the plurality of grooves711are formed in the first region211a. With this configuration, the plurality of grooves711formed in the first region211aare filled with the bonding material3. Accordingly, due to the anchor effect, the adhesion strength of the bonding material3to the die pad portion21(the first region211a) increases. Furthermore, the plurality of grooves711are formed through laser processing, and thus fine irregularities are formed on the surfaces of the plurality of grooves711. Accordingly, due to the anchor effect, the adhesion strength of the bonding material3to the die pad portion21(the first region211a) can be further improved.

In the electronic device A1, the resin member5is the second composition (for example, an epoxy resin) in the form of a solid. The plurality of grooves721are formed in the second region211b, and due to the plurality of grooves721, the second region211bhas a lyophilicity for the second composition in the form of a liquid. With this configuration, the plurality of grooves721formed in the second region211bare filled with the resin member5. Accordingly, due to the anchor effect, the adhesion strength of the resin member5to the die pad portion21(the second region211b) increases. Furthermore, the plurality of grooves721are formed through laser processing, and thus fine irregularities are formed on the surfaces of the plurality of grooves721. Accordingly, due to the anchor effect, the adhesion strength of the resin member5to the die pad portion21(the second region211b) can be further improved.

FIGS.14and15show an electronic device according to a second embodiment. An electronic device A2according to the second embodiment is different from the electronic device A1in that the electronic device A2further includes a third region211cin the obverse surface211of the die pad portion21.FIG.14is a plan view of the electronic device A2. InFIG.14, the electronic component1, the bonding material3, and the resin member5are indicated by imaginary lines, and an illustration of the connecting members4is omitted.FIG.15is a cross-sectional view taken along the line XV-XV shown inFIG.14.

The third region211cis provided between the first region211aand the second region211bas viewed in a plan view. The third region211chas, for example, a rectangular annular shape as viewed in a plan view. The third region211cis configured such that an inner edge thereof is in contact with the outer edge of the first region211a, and an outer edge thereof is in contact with the inner edge of the second region211bas viewed in a plan view. No grooves are formed in the third region211c, and the third region211cis flat. The third region211cis plated with, for example, an Ag coating (a silver coating). As shown inFIG.15, the third region211cis in contact with the bonding material3. In the present embodiment, the second surface32of the bonding material3is in contact with both the first region211aand the third region211c, and the second surface32of the bonding material3overlaps the first region211aand the third region211cas viewed in a plan view. However, the third region211cmay have a configuration different from the example shown inFIG.15. The third region211cmay be configured by forming a plurality of grooves711continuously from the first region211aand plating the plurality of grooves711with an Ag coating. The third region211cis formed in the step of forming the first region211aand the second region211bin the die pad portion21of the lead frame2.

Due to the Ag coating that has been formed, the third region211chas a lyophilicity for the first composition in the form of a liquid. The third region211chas a higher lyophilicity for the first composition in the form of a liquid than that of the first region211a. As described above, the first region211ahas a higher lyophilicity for the first composition in the form of a liquid than that of the second region211b, and thus the third region211chas a higher lyophilic for the first composition in the form of a liquid than that of the second region211b.

The method for manufacturing the electronic device A2is different from the method for manufacturing the electronic device A1in that the third region211cis formed. Other than this, the method for manufacturing the electronic device A2is substantially the same as the method for manufacturing the electronic device A1.

In the electronic device A2, the obverse surface211of the die pad portion21(the lead frame2) includes the first region211awhere the plurality of grooves711are formed, and the bonding material3is in contact with the first region211a. With this configuration, in the electronic device A2, as with the electronic device A1, the bonding material3is not formed in the second region211bthat surrounds the first region211a, and thus the likelihood of the thickness of the bonding material3being thin or non-uniform in the first region211acan be suppressed. Accordingly, with the electronic device A2, as with the electronic device A1, the reliability can be improved.

In the electronic device A2, in the obverse surface211of the die pad portion21, the third region211cis formed between the first region211aand the second region211bas viewed in a plan view. The third region211chas a higher lyophilicity for the first composition in the form of a liquid than that of the second region211b. With this configuration, when the bonding material3turns into a liquid during the process of manufacturing the electronic device A2(reflow processing), the bonding material3in the form of a liquid tends to remain in the third region211cthat has a relatively high lyophilicity for the first composition in the form of a liquid, and it is therefore possible to prevent the bonding material3in the form of a liquid from spreading to the second region211bthat has a relatively low lyophilicity for the first composition in the form of a liquid. Accordingly, in the electronic device A2, as a result of the third region211chaving a higher lyophilicity for the first composition in the form of a liquid than that of the second region211b, the likelihood of the bonding material3in the form of a liquid flowing to the second region211bcan be suppressed.

In the electronic device A2, the third region211chas a higher lyophilicity for the first composition in the form of a liquid than that of the first region211a. With this configuration, the difference in the lyophilicity for the first composition in the form of a liquid at a boundary between the third region211cand the second region211bis larger than that at a boundary between the first region211aand the second region211b. Accordingly, in the electronic device A2, it is possible to more effectively suppress the likelihood of the bonding material3in the form of a liquid flowing to the second region211b, as compared with the electronic device A1. That is, with the electronic device A2, the reliability can be further improved as compared with the electronic device A1.

Other than the foregoing, the electronic device A2has the same configuration as that of the electronic device A1, and thus can provide the same advantageous effects as those of the electronic device A1.

In the second embodiment, an example was described in which the third region211cis plated with an Ag coating such that the third region211chas a lyophilicity for the first composition (the bonding material3) in the form of a liquid, and the lyophilicity of the third region211cfor the first composition in the form of a liquid is higher than that of the first region211a, but the configuration is not limited thereto. Instead of plating the third region211cwith an Ag coating, a coating agent or the like may be used as long as the third region211chas a higher lyophilicity for the first composition in the form of a liquid than that of the first region211a.

FIGS.16and17show an electronic device according to a third embodiment. An electronic device A3according to the third embodiment is different from the electronic device A2in that the third region211cis recessed relative to the first region211aand the second region211b.FIG.16is a plan view of the electronic device A3. InFIG.16, the electronic component1, the bonding material3, and the resin member5are indicated by imaginary lines, and an illustration of the connecting members4is omitted.FIG.17is a cross-sectional view taken along the line XVII-XVII shown inFIG.16.

In the electronic device A3, as described above, the third region211cis recessed relative to the first region211aand the second region211b. In the third region211c, a groove731that surrounds the first region211ais formed. As shown inFIG.17, the third region211cof the present embodiment is not in contact with the bonding material3. In the present embodiment, the second surface32of the bonding material3is in contact with the first region211a, and is not in contact with the third region211c. Also, the third surface33of the bonding material3is configured such that a portion (the outer periphery as viewed in a plan view) thereof does not overlap the second region211b, and overlaps the third region211cas viewed in a plan view. The groove731has, for example, a rectangular annular shape as viewed in a plan view, and an inner edge of the groove731is connected to the outer edge of the first region211aand an outer edge of the groove731is connected to the inner edge of the second region211b. The groove731has a width of, for example, about 50 to 200 μm and a depth of, for example, about 30 to 100 μm. The groove731may be formed through, for example, laser processing or etching.

The method for manufacturing the electronic device A3is different from the method for manufacturing the electronic device A2in that the third region211cis formed in a different manner. Other than this, the method for manufacturing the electronic device A3is substantially the same as the method for manufacturing the electronic device A2.

In the electronic device A3, the obverse surface211of the die pad portion21(the lead frame2) includes a first region211awhere a plurality of grooves711are formed, and the bonding material3is in contact with the first region211a. With this configuration, in the electronic device A3, as with the electronic device A1, the bonding material3is not formed in the second region211bthat surrounds the first region211a, and thus the likelihood of the thickness of the bonding material3being thin or non-uniform in the first region211acan be suppressed. Accordingly, with the electronic device A3, as with the electronic device A1, the reliability can be improved.

In the electronic device A3, in the obverse surface211of the die pad portion21, the third region211cis formed between the first region211aand the second region211bas viewed in a plan view. In the third region211c, the groove731is formed, and due to the groove731, the third region211cis recessed toward the lower side in the z direction from the first region211aand the second region211b. With this configuration, in the process of manufacturing the electronic device A3(reflow processing), the bonding material3in the form of a liquid remains in the first region211aby the action of surface tension at a boundary between the first region211aand the third region211c, and thus the likelihood of the bonding material3flowing to the third region211cis suppressed. For this reason, the bonding material3is not in contact with the third region211c. Accordingly, with the electronic device A3, the likelihood of the bonding material3in the form of a liquid flowing to the second region211bcan be suppressed. That is, with the electronic device A3, the reliability can be improved.

Other than the foregoing, the electronic device A3has the same configuration as that of the electronic device A1(or A2), and thus can provide the same advantageous effects as those of the electronic device A1(or A2).

FIGS.18and19show an electronic device according to a fourth embodiment. An electronic device A4according to the fourth embodiment is different from the electronic device A2in that the third region211chas a liquid repellency to the first composition in the form of a liquid.FIG.18is a plan view of the electronic device A4. InFIG.18, the electronic component1, the bonding material3, and the resin member5are indicated by imaginary lines, and an illustration of the connecting members4is omitted.FIG.19is a cross-sectional view taken along the line XIX-XIX shown inFIG.18.

In the electronic device A4, as shown inFIG.19, the third region211cis not in contact with the bonding material3. In the present embodiment, the second surface32of the bonding material3is in contact with the first region211a, and is not in contact with the third region211c. Also, the third surface33of the bonding material3is configured such that a portion (the outer periphery as viewed in a plan view) thereof does not overlap the second region211b, and overlaps the third region211cas viewed in a plan view. As described above, the third region211chas a liquid repellency to the first composition in the form of a liquid. That is, because the first composition is solder, the third region211chas a low solder wettability. A groove731is formed in the third region211c, and in the groove731, a plurality of protrusions that protrude toward the upper side in the z direction from the bottom surface of the groove731are formed. Accordingly, the third region211cis a rough surface with a plurality of protrusions. The third region211chas a surface structure (shape) that is similar to, for example, the surface structure (shape) of a lotus leaf, a taro leaf, or the like. Due to the surface structure, the third region211chas a liquid repellency to the first composition in the form of a liquid. The groove731may be formed through, for example, laser processing or etching.

The method for manufacturing the electronic device A4is different from the method for manufacturing the electronic device A2in that the third region211cis formed in a different manner. Other than this, the method for manufacturing the electronic device A4is substantially the same as the method for manufacturing the electronic device A2.

In the electronic device A4, the obverse surface211of the die pad portion21(the lead frame2) includes the first region211awhere the plurality of grooves711are formed, and the bonding material3is in contact with the first region211a. With this configuration, in the electronic device A4, as with the electronic device A1, the bonding material3is not formed in the second region211bthat surrounds the first region211a, and thus the likelihood of the thickness of the bonding material3being thin or non-uniform in the first region211acan be suppressed. Accordingly, with the electronic device A4, as with the electronic device A1, the reliability can be improved.

With the electronic device A4, in the obverse surface211of the die pad portion21, the third region211cis formed between the first region211aand the second region211bas viewed in a plan view. The third region211chas a liquid repellency to the first composition in the form of a liquid. With this configuration, in the process for manufacturing the electronic device A4(reflow processing), the bonding material3in the form of a liquid remains in the first region211aby the action of surface tension at a boundary between the first region211aand the third region211c, and thus the likelihood of the bonding material3flowing to the third region211cis suppressed. For this reason, the bonding material3is not in contact with the third region211c. Accordingly, with the electronic device A4, the likelihood of the bonding material3in the form of a liquid flowing to the second region211bcan be suppressed. That is, with the electronic device A4, the reliability can be improved.

Other than the foregoing, the electronic device A4has the same configuration as that of the electronic device A1(A2or A3), and thus can provide the same advantageous effects as those of the electronic device A1(A2or A3).

FIGS.20to23show an electronic device according to a fifth embodiment. An electronic device A5according to the fifth embodiment is different from the electronic device A1primarily in that the lead frame2has a different configuration.

FIG.20is a plan view of the electronic device A5. InFIG.20, the resin member5is indicated by an imaginary line.FIG.21is a partially enlarged view of a relevant part ofFIG.20. InFIG.20, the electronic component1and the resin member5are indicated by imaginary lines, and an illustration of the bonding material3and the connecting members4is omitted.FIG.22is a side view (right side view) of the electronic device A5. In FIG.22, the resin member5is indicated by an imaginary line.FIG.23is a cross-sectional view taken along the line XXIII-XXIII shown inFIG.20.

The electronic device A5is configured in a so-called TO (Transistor Outline) package.

In the electronic device A5, as shown inFIG.23, each of the electrode pads13provided in the electronic component1includes an obverse surface electrode131and a reverse surface electrode132. The obverse surface electrode131is exposed at the obverse surface11, and the reverse surface electrode132is exposed at the reverse surface12. The reverse surface electrode132is electrically connected to the die pad portion21(the lead frame2) via the bonding material3. Accordingly, the bonding material3according to the present embodiment is conductive.

In the lead frame2, one of the plurality of terminal lead portions23is connected to the die pad portion21. In the electronic device A5, as shown inFIG.20, the terminal lead portion23that is disposed at the center in the x direction is connected to the die pad portion21. The terminal lead portion23that is connected to the die pad portion21does not include a pad portion231, and includes a terminal portion232. Also, the terminal lead portions23protrude from the resin member5.

In the lead frame2, as with the electronic device A1, the obverse surface211of the die pad portion21includes the first region211aand the second region211b. The first region211aand the second region211bhave the same configurations as those of the electronic device A1. In the electronic device A5, as shown inFIG.21, the plurality of grooves711formed in the first region211ahave a linear shape extending the y direction, and are arranged in parallel to each other. Likewise, the plurality of grooves721formed in the second region211bhave a linear shape extending in the y direction, and are arranged in parallel to each other. As with the electronic device A1, the plurality of grooves711and the plurality of grooves721may have a linear shape extending in the x direction.

The method for manufacturing the electronic device A5is different from the method for manufacturing the electronic device A1in that a different lead frame2is prepared. Other than this, the method for manufacturing the electronic device A5is substantially the same as the method for manufacturing the electronic device A1.

In the electronic device A5, the obverse surface211of the die pad portion21(the lead frame2) includes the first region211awhere the plurality of grooves711are formed, and the bonding material3is in contact with the first region211a. With this configuration, in the electronic device A5, as with the electronic device A1, the bonding material3is not formed in the second region211bthat surrounds the first region211a, and thus the likelihood of the thickness of the bonding material3being thin or non-uniform in the first region211acan be suppressed. Accordingly, with the electronic device A5, as with the electronic device A1, the reliability can be improved.

Other than the foregoing, the electronic device A5has the same configuration as that of the electronic device A1, and thus can provide the same advantageous effects as those of the electronic device A1.

In the fifth embodiment, an example was described in which the first region211aand the second region211bare formed in the obverse surface211of the die pad portion21of the lead frame2, but the configuration is not limited thereto. In the obverse surface211, for example, the third region211caccording to any one of the second to fourth embodiments may also be formed. In this case, the same advantageous effects as those of any one of the second to fourth embodiments can be provided.

In each of the first to fifth embodiments, an example was described in which the plurality of grooves711formed in the first region211ahave a linear shape, and are arranged in parallel to each other as viewed in a plan view, but the configuration is not limited thereto. For example, the plurality of grooves711may have a linear shape and be arranged in a mesh as viewed in a plan view.FIG.24shows the first region211awhere the plurality of linear grooves711are arranged in a mesh as viewed in a plan view. In this case, the lyophilicity for the first composition in the form of a liquid and the lyophilicity for the second composition in the form of a liquid may be changed by adjusting a width W11of the grooves711and a width W12of the grooves711(seeFIG.24) as well as a spacing P11between grooves711and a spacing P12between grooves711(seeFIG.24). In the present variation as well, the first region211ahas a lyophilicity for the first composition in the form of a liquid. The same applies to the plurality of grooves721that are formed in the second region211b. That is, the plurality of grooves721may have a linear shape, and be arranged in a mesh as viewed in a plan view.

In each of the first to fifth embodiments, an example was described in which the plurality of grooves711formed in the first region211ahave a linear shape as viewed in a plan view, but the configuration is not limited thereto. For example, the plurality of grooves711may have a circular shape (dot shape) and be arranged in a matrix as viewed in a plan view.FIG.25shows the first region211awhere the plurality of circular grooves711are arranged in a matrix as viewed in a plan view. In this case, the lyophilicity for the first composition in the form of a liquid and the lyophilicity for the second composition in the form of a liquid may be changed by adjusting the width W1of the grooves711(diameter) (seeFIG.25) and an arrangement spacing Px between grooves711and an arrangement spacing Py between grooves711(seeFIG.25). In the present variation as well, the first region211ahas a lyophilicity for the first composition in the form of a liquid. The same applies to the plurality of grooves721that are formed in the second region211b. That is, the plurality of grooves721may have a circular shape and be arranged in a matrix as viewed in a plan view.

In each of the first to fifth embodiments, an example was described in which the plurality of grooves711formed in the first region211ahave a linear shape as viewed in a plan view, but the configuration is not limited thereto. For example, the plurality of grooves711may be in the shape of a wave-shaped or crank-shaped curve as viewed in a plan view. For example, the grooves711in the shape of a wave-shaped or crank-shaped curve as viewed in a plan view may be formed by moving laser light in the shape of a wave or a crank instead of linearly moving laser light during the formation of the grooves711. As used herein, the term “crank-shaped” is not limited to a shape with a right bending angle, but also encompasses a shape with an acute bending angle and a shape with an obtuse bending angle. In the present variation as well, the first region211ahas a lyophilicity for the first composition in the form of a liquid. The same applies to the plurality of grooves721that are formed in the second region211b. That is, the plurality of grooves721may be in the shape of a wave-shaped or crank-shaped curve as viewed in a plan view.

In the first to fifth embodiments, the arrangement patterns of the plurality of grooves711formed in the first region211a, the plurality of grooves721formed in the second region211b, and the groove731formed in the third region211care not limited to those described above. The first region211a, the second region211b, and the third region211cmay be configured to have lyophilicity or liquid repellency described above. For example, the grooves711,721, and731may be arranged in an arrangement pattern based on well-known biomimetics so as to have lyophilicity or liquid repellency.

In each of the first to fifth embodiments, an example was described in which the electronic device includes one electronic component1, but the electronic device may include a plurality of electronic components1. In this case, the first region211ais formed on the lower side of an electronic component1, and an electronic component1may be bonded onto the first region211avia the bonding material3.

In each of the first to fifth embodiments, an example was shown in which a plurality of grooves721are formed in the second region211b. However, the configuration is not limited thereto. For example, the second region211bmay be flat.

The electronic device and the method for manufacturing an electronic device according to the present disclosure are not limited to the embodiments given above. Various modifications can be made to the designs of specific configurations of the constituent elements of the electronic device of the present disclosure and specific processing operations of the steps of the method for manufacturing an electronic device of the present disclosure.

The electronic device and the method for manufacturing an electronic device according to the present disclosure encompass embodiments recited in the following clauses.

Clause 1.

An electronic device comprising:

an electronic component;

a support member that includes a mount surface on which the electronic component is mounted; and

a bonding material that is provided between the electronic component and the support member to fixedly attach the electronic component to the support member,

wherein the mount surface includes a first region where a plurality of grooves are formed and a second region that surrounds the first region as viewed in a first direction, and

the bonding material is in contact with the first region, and is not in contact with the second region.

Clause 2.

The electronic device according to Clause 1, wherein the bonding material contains a first composition in the form of a solid, andthe first region has a lyophilicity for the first composition in the form of a liquid, and the lyophilicity for the first composition in the form of a liquid is higher than that of the second region.
Clause 3.

The electronic device according to Clause 2, wherein the first composition is solder.

Clause 4.

The electronic device according to Clause 2 or 3, wherein the mount surface further includes a third region that is provided between the first region and the second region as viewed in the first direction.

Clause 5.

The electronic device according to Clause 4, wherein the third region is in contact with the bonding material.

Clause 6.

The electronic device according to Clause 5, wherein the third region has a higher lyophilicity for the first composition in the form of a liquid than that of the first region.

Clause 7.

The electronic device according to Clause 5 or 6, wherein the third region is plated with an Ag coating.

Clause 8.

The electronic device according to Clause 4, wherein the third region is not in contact with the bonding material.

Clause 9.

The electronic device according to Clause 8, wherein the third region is recessed relative to the first region and the second region.

Clause 10.

The electronic device according to Clause 8, wherein the third region has a liquid repellency to the first composition in the form of a liquid.

Clause 11.

The electronic device according to any one of Clauses 1 to 10, further comprising:a resin member that covers the electronic component and the mount surface,wherein the resin member contains a second composition in the form of a solid.
Clause 12.

The electronic device according to Clause 11, wherein the second region has a lyophilicity for the second composition in the form of a liquid.

Clause 13.

The electronic device according to Clause 11 or 12, wherein the second composition is an epoxy resin.

Clause 14.

The electronic device according to any one of Clauses 1 to 13, wherein the support member includes a die pad portion that includes the mount surface and a terminal lead portion that is spaced apart from the die pad portion.

Clause 15.

The electronic device according to Clause 14, wherein a surface layer of the die pad portion is made of a metal that contains Cu.

Clause 16.

The electronic device according to Clause 14 or 15, further comprising:a connecting member that electrically connects the electronic component and the terminal lead portion.
Clause 17.

The electronic device according to any one of Clauses 1 to 16, wherein a plurality of grooves are formed in the second region, andthe plurality of grooves formed in the second region are different from the plurality of grooves formed in the first region.
Clause 18.

The electronic device according to Clause 17, wherein the plurality of grooves formed in the first region have a width larger than that of the plurality of grooves formed in the second region.

Clause 19.

The electronic device according to Clause 17 or 18, wherein an arrangement spacing between the plurality of grooves formed in the first region is larger than that between the plurality of grooves formed in the second region.

Clause 20.

The electronic device according to any one of Clauses 17 to 19, wherein the plurality of grooves formed in the first region are linear and are arranged in parallel to each other.

Clause 21.

The electronic device according to any one of Clauses 17 to 20, wherein the plurality of grooves formed in the second region are linear and are arranged in parallel to each other.

Clause 22.

The electronic device according to any one of Clauses 1 to 21, wherein the first region has a rectangular shape as viewed in the first direction.

Clause 23.

A method for manufacturing an electronic device, the method comprising:a first step of preparing a support member that includes a mount surface;a second step of forming, in the mount surface, a first region and a second region that surrounds the first region as viewed in a first direction;a third step of applying a bonding material to the first region;a fourth step of placing an electronic component on the bonding material; anda fifth step of heating and cooling the bonding material such that the electronic component is fixedly attached to the support member by the bonding material,wherein, in the second step, the first region is formed by forming a plurality of grooves in a portion of the mount surface, andthe bonding material after the fifth step is in contact with the first region, and is not in contact with the second region.