JP5065657B2 - Electronic device and manufacturing method thereof - Google Patents

Description

  The present invention relates to an electronic device in which an electronic component is mounted on a mounting board, and a method for manufacturing the same.

  Conventionally, as an electronic device of this type, as shown in FIG. 4D, a component-side electrode of an electronic component 3 (here, an IC chip) is mounted on a mounting surface 1a on which a substrate-side electrode 2 of the mounting substrate 1 is formed. In this configuration, the electronic component 3 is mounted on the mounting substrate 1 by connecting the substrate-side electrode 2 and the component-side electrode 4 with the connection surface 3a on which the substrate 4 is formed facing each other.

  When manufacturing the electronic device described above, for example, metal bumps 5 are formed on the substrate side electrode 2 as shown in FIG. 4A, and solder is applied on the component side electrode 4 as shown in FIG. 4B. After the bump 6 'is formed, the substrate side electrode 2 and the component side electrode 4 are aligned, and the electronic component 3 is pressed to the mounting substrate 1 side, whereby the tip of the metal bump 5 is formed as shown in FIG. The portion is embedded in the tip of the solder bump 6 ′. Thereafter, the solder bump 6 'is heated through the electronic component 3, the solder bump 6' is melted and the periphery of the metal bump 5 is wrapped with the solder bump 6 'as shown in FIG. (Metal bump 5) and component side electrode 4 are connected by solder bump 6 '(for example, refer to patent documents 1).

In Patent Document 1, the substrate-side electrode 2 includes a Ni-side layer 2b formed by plating on a substrate-side base electrode layer 2a made of a Cu layer, and an Au layer 2c formed by plating on the Ni layer 2b. The metal bumps 5 are made of Au bumps. The component side electrode 4 has a barrier layer 4c formed on the surface thereof. Further, an underfill material 7 'made of a thermosetting resin adhesive is applied between the mounting surface 1a and the connection surface 3a, and the underfill material 7' is cured when the solder bumps 6 'are heated, so that the underfill material 7' is cured. Fill layer 7 is formed.
Japanese Patent No. 3381593 (page 2-3)

  By the way, in the above-described conventional electronic device, since the solder bump 6 ′ is interposed between the metal bump 5 provided on the substrate side electrode 2 and the component side electrode 4, the metal bump 5 is attached to the component side electrode 4. The conduction resistance between the substrate-side electrode 2 and the component-side electrode 4 is increased by the amount corresponding to the solder bumps 6 'as compared with the case of direct bonding. When the conduction resistance is increased, for example, attenuation of an electric signal may be a problem in an electronic device using a minute electric signal.

  The present invention has been made in view of the above-described reasons, and an object thereof is to provide an electronic device in which a conduction resistance between a substrate-side electrode and a component-side electrode is smaller than that of a conventional configuration and a method for manufacturing the same.

According to the first aspect of the present invention, the board-side electrode and the component-side electrode are connected with the connecting surface of the electronic component on which the component-side electrode is formed facing the mounting surface of the mounting board on which the substrate-side electrode is formed. An electronic device in which an electronic component is mounted on a mounting board by a solder layer provided on the component side electrode, and a metal bump that penetrates the solder layer and contacts the component side electrode on the substrate side electrode. The component-side electrode comprises a component-side base electrode layer, and a deformation-preventing layer formed on the component-side base electrode layer at a site where the metal bump contacts, and the deformation-preventing layer is formed from the solder layer. even hardness rather higher than and metal bumps excellent in conductivity, characterized in that it is squashed tip by a metal bump is pressed against the deformation preventing layer.

  According to this configuration, since the metal bumps are in direct contact with the component side electrode, compared with the conventional configuration in which the solder bump is interposed between the substrate side electrode and the component side electrode, the substrate side electrode and the component The conduction resistance between the side electrodes is reduced. In addition, since a deformation preventing layer having a hardness higher than that of the metal bump is formed at the part where the metal bump contacts the component side electrode, when the metal bump is brought into contact with the component side electrode, the component side electrode Even if a pressing load is applied to the part, deformation and breakage of the component side electrode can be prevented by the deformation preventing layer.

  The invention of claim 2 is characterized in that, in the invention of claim 1, the deformation preventing layer is formed of a nickel layer having a thickness of 3 to 20 μm.

  According to this configuration, the deformation preventing layer can be formed by a relatively simple method such as nickel plating.

  The invention of claim 3 is characterized in that, in the invention of claim 1, the deformation preventing layer is formed of a nickel layer having a thickness of 5 to 20 μm.

  According to this configuration, the deformation preventing layer can be formed by a relatively simple method such as nickel plating. In addition, since the thickness of the deformation prevention layer is at least 5 μm, the hardness of the deformation prevention layer is increased, and a relatively large pressing load acts on the component side electrode from the metal bump when the metal bump is brought into contact with the component side electrode. However, deformation and breakage of the component side electrode can be reliably prevented by the deformation preventing layer.

  According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, the metal bumps are formed of gold stud bumps.

  According to this configuration, since the metal bump is relatively easily deformed, the metal bump is crushed when the metal bump is brought into contact with the component side electrode even when the flatness of the component side electrode or the board side electrode is low. Thus, a large contact area between the metal bump, the component-side electrode, and the substrate-side electrode can be ensured, and the conduction resistance between the substrate-side electrode and the component-side electrode is reduced.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects of the present invention, the structure is interposed between the mounting substrate and the electronic component, and surrounds a joint portion between the metal bump and the component-side electrode. A protective underfill layer is provided.

  According to this configuration, the periphery of the joint portion between the metal bump and the component side electrode is protected by the underfill layer, so that the reliability of the joint portion after the electronic component is mounted on the mounting board is improved.

  A sixth aspect of the present invention is the method of manufacturing an electronic device according to any one of the first to fourth aspects, wherein the component-side substrate forms the component-side electrode of the electronic component together with the deformation prevention layer. A deformation preventing layer forming step of forming the deformation preventing layer on the electrode layer; a solder layer forming step of forming the solder layer on the deformation preventing layer; the metal bumps formed on the substrate side electrode; The solder layer formed on the component side electrode is aligned, the solder layer is heated so that the metal bump penetrates the solder layer and contacts the deformation preventing layer, and the metal bump and the component And a connecting step of pressing one of the side electrodes against the other.

  According to this configuration, since the metal bumps are in direct contact with the component side electrode, compared with the conventional configuration in which the solder bump is interposed between the substrate side electrode and the component side electrode, the substrate side electrode and the component The conduction resistance between the side electrodes is reduced. In addition, since a deformation prevention layer is formed on the component side electrode, even if a pressing load acts on the component side electrode from the metal bump when the metal bump is brought into contact with the component side electrode in the connection process, the component side electrode Can be prevented by the deformation preventing layer.

  The invention according to claim 7 is the method for manufacturing the electronic device according to claim 5, wherein the deformation prevention layer is formed on a component-side base electrode layer constituting the component-side electrode of the electronic component together with the deformation prevention layer. The deformation prevention layer forming step to be formed, the solder layer forming step of forming the solder layer on the deformation prevention layer, the metal bumps formed on the substrate side electrode and the component side electrode A connection that aligns with the solder layer, heats the solder layer so that the metal bump penetrates the solder layer and contacts the deformation prevention layer, and presses one of the metal bump and the component side electrode against the other And an underfill material injection step of injecting an underfill material for forming the underfill layer between the mounting substrate and the electronic component after the connection step. To.

  According to this configuration, since the joint between the metal bump and the component side electrode is protected by the underfill layer by injecting the underfill material, the reliability of the joint after the electronic component is mounted on the mounting substrate. Will improve.

  The invention according to claim 8 is the method for manufacturing the electronic device according to claim 5, wherein the deformation prevention layer is formed on a component-side base electrode layer constituting the component-side electrode of the electronic component together with the deformation prevention layer. The deformation prevention layer forming step to be formed, the solder layer forming step of forming the solder layer on the deformation prevention layer, the metal bumps formed on the substrate side electrode and the component side electrode A connection that aligns with the solder layer, heats the solder layer so that the metal bump penetrates the solder layer and contacts the deformation prevention layer, and presses one of the metal bump and the component side electrode against the other An underfill for applying a thermosetting underfill material to a portion of the mounting substrate facing the connection surface of the electronic component between the solder layer forming step and the connecting step. Has a coating step, in the connecting step, and forming the underfill layer by curing by heating the solder layer at the same time as the under-fill material.

  According to this configuration, since the underfill material is heated and cured simultaneously with the solder layer in the connection process, the process can be simplified compared to the case where there is a process only for curing the underfill material, Tact time can be shortened.

  According to a ninth aspect of the present invention, in the invention according to any one of the sixth to eighth aspects, in the connecting step, the electronic component is heated to a temperature equal to or higher than a melting point of the solder layer, and the temperature of the mounting substrate is set to the solder. It is characterized by being maintained below the melting point of the layer.

  According to this configuration, in the connection process, the temperature of the mounting board is maintained below the melting point of the solder layer while melting the solder layer on the component-side electrode, so that other components already mounted on the mounting board It is possible to avoid melting up to the solder joint.

  According to a tenth aspect of the present invention, in the eighth aspect of the invention, in the state in which the connecting step heats the electronic component to a temperature below the melting point of the solder layer, the metal bump penetrates the solder layer and the deformation occurs. A first step of applying pressure so as to contact the prevention layer; and after the first step, the electronic component is heated to a temperature equal to or higher than a melting point of the solder layer to join the metal bump and the deformation prevention layer with the solder layer. And a second stage for curing the underfill material.

  According to this configuration, since the metal bumps are pressed against the component-side electrode in the first stage where the solder layer is not melted, the solder layer flows due to the spreading of the underfill material in the first stage. In addition, there is an advantage that a good solder layer fillet can be formed on the metal bumps in the second stage.

  In the present invention, since the metal bump is in direct contact with the component side electrode by contacting the deformation preventing layer having higher conductivity than the solder layer, the solder bump is interposed between the substrate side electrode and the component side electrode. Compared to the conventional configuration, the conduction resistance between the substrate side electrode and the component side electrode is reduced. In addition, since the deformation prevention layer is harder than the metal bump, even if a pressing load acts on the component side electrode from the metal bump when the metal bump is brought into contact with the component side electrode, the component side electrode is not deformed or damaged. There is an advantage that it can be prevented by the deformation preventing layer.

(Embodiment 1)
As shown in FIG. 1B, the electronic device according to the present embodiment has a mounting substrate 1 in a form in which a substrate-side electrode 2 formed on the mounting substrate 1 and a component-side electrode 4 formed on the electronic component 3 are connected. And an electronic component 3 mounted thereon. As shown in FIG. 1A, the substrate-side electrode 2 is formed on a mounting surface 1a that is one surface of the mounting substrate 1, and the component-side electrode 4 is a connection surface 3a that is a surface facing the mounting surface 1a of the electronic component 3. The electronic component 3 is flip-chip mounted on the mounting substrate 1.

  In this embodiment, the mounting substrate 1 is made of a glass epoxy substrate, and metal bumps 5 made of Au stud bumps formed of Au wires are provided on the substrate-side electrode 2. The substrate side electrode 2 is formed by plating a Ni layer 2b on a substrate side base electrode 2a made of a Cu layer and further an Au layer 2c (bonding Au plating) on the substrate side electrode 2a so that the metal bumps 5 can be formed. It has the structure made.

  On the other hand, a solder layer 6 made of Pb (lead) -free solder is formed on the component-side electrode 4 of the electronic component 3 (here, an IC chip). As the Pb-free solder, Sn—Ag, Sn—Bi, Sn—Zn and the like are used. The solder layer 6 is formed on the component side electrode 4 by electroless solder plating.

  The component side electrode 4 has a configuration in which a Ni layer (nickel layer) having a thickness of 3 to 20 μm (preferably 5 to 20 μm) is formed as a deformation preventing layer 4b on a component side base electrode layer 4a made of an Al layer. . The deformation preventing layer 4b is formed on the component-side base electrode layer 4a by electroless plating. The thickness dimension of the deformation preventing layer 4b can be increased by increasing the plating time. The deformation prevention layer 4 b is formed with higher conductivity than the solder layer 6 and higher hardness than the metal bump 5. Furthermore, since the deformation preventing layer 4b is an Ni layer, the deformation preventing layer 4b also serves as a barrier layer for preventing the solder layer 6 from diffusing into the component-side base electrode layer 4a.

  The metal bump 5 described above penetrates the solder layer 6 and contacts the component side electrode 4, thereby electrically connecting the substrate side electrode 2 and the component side electrode 4. In the present embodiment, since the deformation preventing layer 4b is formed on the surface of the component side electrode 4, the metal bump 5 contacts the deformation preventing layer 4b in a state where the metal bump 5 contacts the component side electrode 4. Become.

  Here, the deformation preventing layer 4b (here, Ni) has a hardness higher than that of the metal bump 5 (here, Au) and has a thickness of 3 μm or more capable of withstanding the pressing load from the metal bump 5, so that the metal bump 5 is formed. Even if a pressing load acts on the component side electrode 4 from the metal bump 5 when contacting the component side electrode 4, the deformation of the electronic component 3 including the component side electrode 4 is received by receiving the pressing load by the deformation preventing layer 4b. And damage can be prevented. That is, as shown in FIG. 1B, the metal bump 5 can be pressed against the component side electrode 4 until the tip end portion of the metal bump 5 is crushed without deforming or damaging the component side electrode 4.

  In the present embodiment, since the Ni layer is the deformation preventing layer 4b, sufficient strength to prevent damage to the component side electrode 4 when the metal bump 5 and the electronic component 3 are joined even when the thickness is 20 μm or less as described above. Can be secured. When flip-chip mounting the electronic component 3 on the mounting substrate 1, the load for pressing the metal bump 5 against the component-side electrode 4 (hereinafter referred to as “mounting load”) is 100 g / bump (that is, a load of 100 g per metal bump). In order to prevent deformation of the deformation prevention layer 4b when flip chip mounting is performed on the component side electrode 4 under a high load condition, such as when the load is high and the heating temperature is 200 ° C. or higher. Further, it is desirable that the thickness of the deformation preventing layer 4b is 5 μm or more.

  Further, since the metal bump 5 is directly connected to the component side electrode 4 by contacting the deformation preventing layer 4b which is more conductive than the solder layer 6, the metal bump 5 is interposed between the substrate side electrode 2 and the component side electrode 4. Compared to the conventional configuration in which the solder bump 6 ′ is interposed, the conduction resistance between the substrate side electrode 2 and the component side electrode 4 is reduced.

  Below, the manufacturing method of the electronic device of this embodiment is demonstrated.

  Metal bumps 5 are formed on the substrate-side electrode 2 of the mounting substrate 1 in a bump forming process. On the other hand, the deformation preventing layer 4b is formed on the component side electrode 4 of the electronic component 3 in the deformation preventing layer forming step. Then, in the solder layer forming step, the solder layer 6 is formed on the deformation preventing layer 4b. Note that either the bump forming step or the deformation preventing layer forming step may be performed first or simultaneously.

  Thereafter, in the connecting step, the electronic component 3 and the metal component 5 are formed so that the metal bump 5 formed on the substrate side electrode 2 and the solder layer 6 formed on the component side electrode 4 abut each other as shown in FIG. Alignment (alignment) with the mounting substrate 1 is performed. Further, in the connection step, as shown in FIG. 1B, the solder layer 6 is heated so that the metal bump 5 penetrates the solder layer 6 and comes into contact with the deformation prevention layer 4b, and the metal bump 5 is made to the component side electrode 4. By pressing, the electronic component 3 is flip-chip mounted on the mounting substrate 1. That is, at the time of flip chip mounting in the connection process, the electronic component 3 and the mounting substrate 1 are pressurized so as to apply a mounting load in a direction to reduce the distance between the electronic component 3 and the mounting substrate 1, and the metal bumps 5 It abuts on the deformation preventing layer 4b.

  At this time, the solder layer 6 is pushed away around the metal bump 5 by the metal bump 5. The pushed solder layer 6 comes into contact with the peripheral surface (side surface) of the metal bump 5 whose tip is crushed by being pressed against the deformation preventing layer 4b. Here, Sn (tin) and Au in the solder layer 6 are easily diffused, and the solder layer 6 and the metal bump 5 are metal-bonded around the tip of the metal bump 5, so that the deformation prevention layer 4 b and the metal bump 5 are formed. It becomes the structure which reinforces joining with.

  Further, since the solder layer 6 is formed on the deformation preventing layer 4b before the connecting step, the contact surface between the deformation preventing layer 4b and the metal bump 5, that is, the interface between the deformation preventing layer 4b and the metal bump 5 is also provided. When a very thin diffusion layer or an intermetallic compound layer in which Ni is diffused into Sn exists, and when the metal bump 5 is heated and pressed on the interface, Au diffuses into the diffusion layer or between the metals. Metal bonding is performed by forming a compound layer.

  These metal bonds are greatly affected by the heating temperature and mounting load during the connection process. That is, in the connecting step, the electronic component 3 side is heated to a temperature equal to or higher than the melting point of the solder layer 6. As a result, the solder layer 6 is melted and the metal bumps 5 and Sn are easily diffused, whereby the strength of the metal bond is improved, and the reliability of the connection state between the board side electrode 2 and the component side electrode 4 after mounting is improved. Will also improve. Moreover, the fillet of the solder layer 6 can be formed by melting the solder layer 6, and the mechanical connection strength is also improved. In the connection step, the component side electrode 4 may be pressed against the metal bump 5.

  Next, a specific example of the electronic device of this embodiment is shown.

  The metal bump 5 is formed from an Au wire having a diameter of 15 to 35 μm. Here, by heating the mounting substrate 1 to 150 to 250 ° C. on the substrate-side electrode 2 of the mounting substrate 1 made of a glass epoxy substrate and applying a load and an ultrasonic wave, the outer diameter is reduced from an Au wire having a diameter of 25 μm. The metal bump 5 having a height of 70 to 80 μm and a height of 90 μm from the surface of the substrate side electrode 2 is formed. The metal bump 5 has a height dimension of 20 to 30 μm from the surface of the substrate-side electrode 2 in a state where the tip portion is crushed by being pressed against the deformation preventing layer 4b in flip chip mounting. The thickness dimension of the Ni layer 2b in the substrate side electrode 2 is 3 to 5 μm, and the thickness dimension of the Au layer 2c is 0.1 to 0.5 μm.

  Moreover, regarding the solder layer 6, if it is the electroless solder plating mentioned above, it can form in thickness of about 3-10 micrometers. Here, when making the thickness dimension of the solder layer 6 larger, a method other than electroless solder plating such as solder dipping may be used. If it is a solder dip, the solder layer 6 with a thickness of 3 to 60 μm can be formed. However, when the thickness dimension of the solder layer 6 increases, the solder layer 6 contacts the substrate side electrode 2 when the electronic component 3 is mounted and spreads out, and contacts the adjacent component side electrode 4 or the substrate side electrode 2 to cause a short circuit. Since there is a possibility, it is desirable to suppress the thickness dimension of the solder layer 6 to 15 μm or less. On the other hand, in the configuration in which the solder bump 6 ′ is provided on the component side electrode 4 as in the electronic device shown as the conventional configuration, the solder bump 6 ′ wraps around the metal bump 5 when melted. Since the amount must be relatively large, when the component side electrodes 4 are arranged at a narrow pitch, the adjacent component side electrodes 4 (or the substrate side electrodes 2) with the melted solder bumps 6 '. May be short-circuited.

  In the above-described embodiment, the glass epoxy substrate is exemplified as the mounting substrate 1. However, the present invention is not limited to this example. For example, a ceramic substrate may be used as the mounting substrate 1. Moreover, although the example which formed the deformation | transformation prevention layer 4b on the component side base electrode layer 4a which consists of Al layers as the component side electrode 4 was shown, it does not restrict to this example, for example on the component side base electrode layer which consists of Cu layers The component side electrode 4 may be configured by forming the deformation preventing layer 4b.

(Embodiment 2)
As shown in FIG. 2B, the electronic device of the present embodiment is interposed between the mounting surface 1 a of the mounting substrate 1 and the connection surface 3 a of the electronic component 3, and the metal bump 5 and the component-side electrode 4 The electronic device according to the first embodiment is different from the electronic device according to the first embodiment in that an underfill layer 7 that protects the periphery of the joint is provided.

  The underfill layer 7 is formed by curing an underfill material 7 ′ (see FIG. 3B) made of a thermosetting insulating resin material mainly composed of an epoxy resin filled with a filler. The underfill layer 7 protects the joint by sealing the periphery of the joint between the metal bump 5 and the component side electrode 4.

  If there is no underfill layer 7 and the electronic device undergoes a temperature change, such as after the electronic device is heated in the connection process, the thermal stress due to the difference in coefficient of thermal expansion between the electronic component 3 and the mounting substrate 1 will cause metal bumps. 5 may be concentrated on the joint between the component side electrode 4 and the component side electrode 4, and a crack may occur in the joint. On the other hand, in this embodiment provided with the underfill layer 7, the thermal stress acting on the joint portion can be reduced by receiving the thermal stress in the underfill layer 7.

  Below, the manufacturing method of this embodiment is demonstrated. The process up to the connection step of flip-chip mounting the electronic component 3 on the mounting substrate 1 as shown in FIG.

  After the connecting step, as shown in FIG. 2B, the underfill material 7 is formed in the gap g1 (see FIG. 2A) formed between the mounting surface 1a of the mounting substrate 1 and the connecting surface 3a of the electronic component 3. 'Is injected (underfill material injection process). Then, the underfill material 7 ′ is heated to cure the underfill material 7 ′ in the state of FIG. 2B to form the underfill layer 7 (underfill material curing step).

  In the present embodiment, as an example, an underfill material 7 ′ that is cured in 1 to 3 hours while being heated to 150 ° C. is employed. Other configurations and functions are the same as those of the first embodiment.

(Embodiment 3)
As shown in FIG. 3B, the electronic device of the present embodiment is that the underfill material 7 ′ is applied to a part of the mounting surface 1a of the mounting substrate 1 before the connecting step, as shown in FIG. Is different.

  The underfill material 7 ′ is applied to the mounting substrate 1 after the bump forming process, the deformation preventing layer forming process, and the solder layer forming process are completed, and in the underfill material applying process before the connecting process. The underfill material 7 ′ is applied to a part of the mounting surface 1 a that faces the connection surface 3 a of the electronic component 3 in a state where the electronic component 3 is mounted. In this embodiment, the underfill material 7 ′ is applied as shown in FIG. As described above, the underfill material 7 ′ is applied to the portion surrounded by the substrate-side electrode 2. The underfill material 7 ′ thus applied is cured in the connecting step shown in FIG. In short, in the connecting step, as shown in FIG. 3C, the solder layer 6 is heated so that the metal bump 5 penetrates the solder layer 6 and comes into contact with the deformation preventing layer 4b, and the metal bump 5 is moved to the component side electrode 4. The underfill material 7 ′ is heated and cured simultaneously with the solder layer 6.

  Here, in the connection step, the electronic component 3 needs to be heated to a temperature equal to or higher than the melting point of the solder layer 6 in order to melt the solder layer 6. It is desirable to maintain the temperature below the melting point of the solder layer 6 in order to avoid melting to the solder joints of other parts already mounted on the solder layer 6. Therefore, in the present embodiment, the temperature is set so that the electronic component 3 can be heated to a temperature equal to or higher than the melting point of the solder layer 6 in a crimping tool (not shown) that heats and pressurizes the electronic component 3 during flip chip mounting. In the stage (not shown) for fixing the mounting substrate 1, the temperature is set so that the mounting substrate 1 is maintained at a temperature lower than the melting point of the solder layer 6.

  In the present embodiment, the solder layer 6 having a melting point higher than the curing temperature of the underfill material 7 ′ is employed. For this reason, it is desirable to raise the heating temperature above the melting point of the solder layer 6 during the curing of the underfill material 7 ′ so that the flow of the molten solder layer 6 is not hindered by the underfill material 7 ′.

  By the way, in the method of mounting the electronic component 3 on the mounting substrate 1 after applying the underfill material 7 ′, the gap between the electronic component 3 and the mounting substrate 1 flows when the pressure is applied. G1 spreads and fills the gap g1, but if the solder layer 6 is in a molten state at this time, the molten solder layer 6 flows along with the flow of the underfill material 7 ′, and the metal bumps 5 and There is a possibility that a good connection state with the component side electrode 4 cannot be secured by the solder layer 6. Therefore, in the present embodiment, in a state where the heating temperature is set to a temperature lower than the melting point of the solder layer 6, the metal bump 5 penetrates the solder layer 6 and is pressed so as to contact the deformation preventing layer 4 b and is held for a certain time. The first stage and after the first stage are set, and the heating temperature is raised to the melting point of the solder layer 6 or higher and held for a certain period of time, thereby joining the metal bump 5 and the deformation preventing layer 4b with the solder layer 6 and underfilling. The connection process is divided into the second stage in which the material 7 'is cured.

  According to this configuration, when the underfill material 7 ′ flows due to pressurization, the solder layer 6 is not melted, and the flow of the underfill material 7 ′ stops and the fillet of the underfill material 7 ′ is formed. Later, since the solder layer 6 is melted and the metal bump 5 and the component side electrode 4 are metal-bonded, a good connection state between the metal bump 5 and the component side electrode 4 can be ensured. In the first stage, since the solder layer 6 is softened by heating although it is less than the melting point, the metal bump 5 can be brought into contact with the component side electrode 4 through the solder layer 6. is there. At this time, the solder layer 6 is pushed away around the metal bump 5, and the pushed-out portion comes into contact with the peripheral surface (side surface) of the tip portion of the crushed metal bump 5. When 6 is heated to the melting point or higher, it melts to form a metal bond.

  In the present embodiment, since the underfill material 7 ′ is cured simultaneously with the flip chip mounting, it is desirable to employ the underfill material 7 ′ that is cured in a short time in order to shorten the tact time. An underfill material 7 ′ that cures within 20 seconds in a state heated to ˜300 ° C. is employed. In this case, when performing heating for melting the solder layer 6 in the connection step, the electronic component 3 is heated to 220 to 250 ° C. at a temperature equal to or higher than the melting point of the solder layer 6, and the mounting substrate 1 is soldered. The temperature below the melting point of the layer 6 is maintained at 100 ° C. or lower (for example, 30 ° C.). Other configurations and functions are the same as those of the second embodiment.

It is explanatory drawing of the manufacturing method of Embodiment 1 of this invention. It is explanatory drawing of the manufacturing method of Embodiment 2 of this invention. It is explanatory drawing of the manufacturing method of the actual child form 3 of this invention. It is explanatory drawing of the manufacturing method of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mounting substrate 1a Mounting surface 2 Substrate side electrode 3 Electronic component 3a Connection surface 4 Component side electrode 4a Component side base electrode layer 4b Deformation prevention layer 5 Metal bump 6 Solder layer 7 Underfill layer 7 'Underfill material

Claims (10)

An electronic component is mounted on the mounting substrate by connecting the substrate-side electrode and the component-side electrode with the connecting surface of the electronic component facing the mounting surface of the mounting substrate on which the substrate-side electrode is formed. In the mounted electronic device, a solder layer is provided on the component side electrode, and a metal bump that penetrates the solder layer and contacts the component side electrode is provided on the substrate side electrode. A component-side base electrode layer, and a deformation-preventing layer formed on the component-side base electrode layer at a portion where the metal bumps abut , the deformation-preventing layer being superior in conductivity and metal to the solder layer. hardness than bumps rather high, the electronic device, wherein the metal bump tip is crushed by being pressed against the deformation preventing layer.   The electronic device according to claim 1, wherein the deformation preventing layer is formed of a nickel layer having a thickness of 3 to 20 μm.   The electronic device according to claim 1, wherein the deformation preventing layer is formed of a nickel layer having a thickness of 5 to 20 μm.   4. The electronic device according to claim 1, wherein the metal bumps are formed of gold stud bumps. 5.   5. The underfill layer that is interposed between the mounting substrate and the electronic component and protects the periphery of the joint portion between the metal bump and the component side electrode. The electronic device according to claim 1.   5. The method of manufacturing an electronic device according to claim 1, wherein the deformation prevention is performed on a component-side base electrode layer that constitutes the component-side electrode of the electronic component together with the deformation prevention layer. A deformation preventing layer forming step for forming a layer; a solder layer forming step for forming the solder layer on the deformation preventing layer; and the metal bumps formed on the substrate side electrode and the component side electrode. The solder layer is aligned, the solder layer is heated so that the metal bump penetrates the solder layer and contacts the deformation prevention layer, and one of the metal bump and the component side electrode is set to the other. And a connecting step of pressing the electronic device.   6. The method of manufacturing an electronic device according to claim 5, wherein the deformation prevention layer is formed on the component-side base electrode layer constituting the component-side electrode of the electronic component together with the deformation prevention layer. A solder layer forming step of forming the solder layer on the deformation prevention layer, and the metal bumps formed on the substrate side electrode and the solder layer formed on the component side electrode. A connecting step of heating the solder layer so that the metal bump penetrates the solder layer and contacts the deformation preventing layer and presses one of the metal bump and the component side electrode against the other, and An electronic device manufacturing method comprising an underfill material injection step of injecting an underfill material for forming the underfill layer between the mounting substrate and the electronic component after the connecting step. Method.   6. The method of manufacturing an electronic device according to claim 5, wherein the deformation prevention layer is formed on the component-side base electrode layer constituting the component-side electrode of the electronic component together with the deformation prevention layer. A solder layer forming step of forming the solder layer on the deformation prevention layer, and the metal bumps formed on the substrate side electrode and the solder layer formed on the component side electrode. A connecting step of heating the solder layer so that the metal bump penetrates the solder layer and contacts the deformation preventing layer and presses one of the metal bump and the component side electrode against the other, and Between the solder layer forming step and the connecting step, an underfill material applying step of applying a thermosetting underfill material to a portion of the mounting substrate facing the connecting surface of the electronic component, Serial The connection method of manufacturing an electronic device characterized by forming the underfill layer by curing by heating the solder layer at the same time as the under-fill material.   9. The method according to claim 6, wherein, in the connecting step, the electronic component is heated to a temperature equal to or higher than a melting point of the solder layer, and a temperature of the mounting substrate is maintained below a melting point of the solder layer. A method for manufacturing an electronic device according to claim 1.   The connecting step is a first stage of applying pressure so that the metal bump penetrates the solder layer and contacts the deformation preventing layer in a state where the electronic component is heated to a temperature lower than the melting point of the solder layer; After the first step, the electronic component is heated to a temperature equal to or higher than the melting point of the solder layer, thereby joining the metal bumps and the deformation prevention layer with the solder layer and curing the underfill material. The method of manufacturing an electronic device according to claim 8.

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