JP2016219539A - Apparatus and method for joining semiconductor component to metal member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a joint apparatus and joint method that are capable of securing reliability of a joint between a semiconductor component and a metal member even when the temperature of the joint parts becomes high, while using laser light for joining the semiconductor component to the metal member.SOLUTION: A metal member 60 comprises: an opposite surface 61 that forms a laser light passage region, with a first metal film; and a plurality of salients 63 that protrude in an island shape from the opposite surface and have a tip in contact with the first metal film. An aperture 65 that opens outwards is formed at the outer periphery of the laser light passage region. A joint apparatus makes laser light be incident on the laser light passage region, from the aperture; makes part of the laser light be reflected a plurality of times on a metal exposure surface in the laser passage region while making the other part of the laser light be absorbed; and raises temperatures of respective contact surfaces between the first metal film and the tip of the salient until the state of each contact surface becomes a liquid phase state in which the contact surface is melted, or a solid phase state that is established at a temperature lower than that in the liquid phase state and enables joining in a solid state.SELECTED DRAWING: Figure 4A

Description

  The present invention relates to a joining apparatus and joining method for joining a semiconductor component and a metal member by laser light irradiation.

  Conventionally, there is a technique of joining using a laser beam when joining a semiconductor component made of silicon or the like and a metal member. For example, Patent Document 1 describes that a semiconductor chip (semiconductor component) and a base material (metal member) are welded (joined) with laser light having a predetermined infrared wavelength. Specifically, first, a semiconductor component is placed on a metal member, and a bonding material such as solder is disposed between the metal member and the semiconductor component. At this time, an absorbing resin is disposed around the bonding material, and the bonding material is surrounded by the absorbing resin. As the absorbing resin, a member having a better absorption rate of the laser beam having the predetermined infrared wavelength described above than the semiconductor component and the bonding material is used. When the laser beam is irradiated, the laser beam passes through the semiconductor component and is absorbed by the absorbing resin. Thereby, the absorption resin is heated and melted, the bonding material is melted by the heat of the heated absorption resin, and the metal member and the semiconductor component are bonded by the molten bonding material.

JP 2014-150130 A

  In the prior art described in Patent Document 1, it is a necessary condition that the material as the bonding material has a melting temperature lower than the melting temperature of the absorbent resin. For this reason, Patent Literature 1 includes lead-free solder, Sn alloy solder, and the like as selection targets for the bonding material.

  However, in recent years, for example, in an electric vehicle or a hybrid vehicle, a PCU (power control unit) that controls electric power has been increased in voltage and current. For this reason, a high voltage is also applied to a semiconductor component used in an inverter constituting the PCU and a large current flows, so that the temperature between the semiconductor component and the metal member, that is, the bonding material may become high. . In such a case, there is a concern that it is difficult to ensure the quality of the bonding with the above-described bonding material made of lead-free solder, Sn alloy, or the like having a low melting point.

  The present invention has been made in view of such circumstances, and uses a laser beam for joining a semiconductor component and a metal member, and the reliability of the joining between the semiconductor component and the metal member even when the joining portion becomes high temperature. It is an object of the present invention to provide a bonding apparatus and a bonding method capable of securing the property.

  According to a first aspect of the present invention, there is provided a bonding apparatus comprising: a semiconductor main body; a semiconductor component including a first metal film formed on a first surface of the semiconductor main body; and the semiconductor component; A metal member disposed in contact with the first metal film by a laser beam, wherein the metal member is opposed to the first metal film at a distance, A laser beam passing region comprising: a facing surface that forms a laser beam passage region with the metal coating; and a plurality of convex portions that project in an island shape from the facing surface and have tips that contact the first metal coating. An opening that opens outward is formed on the outer periphery of the region, and the bonding apparatus allows the laser light to enter the laser light passage region from the opening, and on a metal exposed surface in the laser light passage region. A portion of the laser beam is reflected multiple times The other part of the laser beam is absorbed while the contact surfaces of the first metal film and the tip part of the convex part are in a melted liquid state, or at a temperature lower than the liquid phase state. Bonding is performed by raising the temperature until a solid phase is obtained that can be joined in a solid state.

  According to the said aspect, the heat which heated up by the 1st metal film and the convex part by absorption of the other part of a laser beam is a side with a high temperature via a contact surface between a 1st metal film and a convex part. The temperature of the contact surface is increased at the same time. Then, when the temperature of the contact surface reaches the melting point of each material forming the first metal film and the convex portion, each contact surface becomes a liquid state that is a molten state, and joining corresponding to normal welding is possible. It becomes. Further, in a state where the temperature of each contact surface is low before reaching the liquid phase state, each contact surface is in a solid phase state, and bonding by solid phase diffusion bonding is possible. By such joining in either the liquid phase state or the solid phase state, the contact surfaces are joined without using solder, so that the heat resistance is improved as compared with the case where the contact surfaces are joined by solder. . As a result, even if the semiconductor component becomes high temperature during use, the reliability of bonding of the contact surfaces between the semiconductor component and the metal member is ensured.

  According to a seventh aspect of the present invention, there is provided a bonding method comprising: a semiconductor body; a semiconductor component including a first metal film formed on a first surface of the semiconductor body; and the semiconductor component formed separately. A metal member disposed in contact with the first metal film by a laser beam, wherein the metal member is opposed to the first metal film at a distance, and A laser beam passing region comprising: a facing surface that forms a laser beam passage region with the metal coating; and a plurality of convex portions that project in an island shape from the facing surface and have tips that contact the first metal coating. In the outer periphery of the region, an opening that opens outward is formed. In the bonding method, the laser light is incident on the laser light passage region from the opening, and the metal exposure surface in the laser light passage region is exposed. A part of the laser beam several times A liquid phase state where the irradiation step of absorbing the other part of the laser light while irradiating and each contact surface between the first metal film and the tip of the convex portion is in a molten state, or the liquid phase state A temperature raising step for raising the temperature to a solid phase that can be bonded in a solid state that is established at a lower temperature, and each contact that has become the liquid phase or the solid phase by the temperature raising step A joining step for joining the surfaces. Thereby, joining similar to the joining obtained with the said joining apparatus with high reliability thermally is obtained.

It is a schematic diagram of a joining device concerning an embodiment. It is a figure explaining the semiconductor component and metal member (heat spreader) which concern on embodiment. It is a top view of a metal member. It is a figure explaining the establishment state of the laser irradiation concerning this invention. It is the Z section enlarged view of Drawing 4A. It is a flowchart of a joining method. It is a figure corresponding to Drawing 4B in a modification.

  A joining apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of the joining apparatus 10. The bonding apparatus 10 includes a laser oscillator 20 (corresponding to an oscillation source of the present invention), a laser head 30 (corresponding to an irradiation angle changing apparatus of the present invention), a reflection unit 40, a casing 70, and a control device 80. The joining device 10 is a device that joins the semiconductor component 50 and the heat spreader 60 (corresponding to the metal member of the present invention) with a laser beam (see FIG. 1). For convenience of description of the bonding apparatus 10, first, the semiconductor component 50 and the heat spreader 60 to be bonded will be described. In the following description, the upper side of FIG. 1 will be described as the upper side, and the lower side as the lower side.

(1. Semiconductor component 50 and heat spreader 60)
As shown in FIGS. 1 and 2, the semiconductor component 50 is used in a PCU (power control unit) that controls electric power, for example, in an electric vehicle or a hybrid vehicle. Specifically, the semiconductor component 50 shall be used as a semiconductor switching element (IGBT) of an inverter constituting the PCU. In addition to the inverter, the semiconductor component 50 is also used for other devices using a semiconductor switching element. In addition, since IGBT is a well-known technique, detailed description is abbreviate | omitted.

  As shown in FIG. 2, the semiconductor component 50 is formed in a flat plate shape. The semiconductor component 50 includes a semiconductor body 51, a first metal film 52, and a second metal film 53. The second metal film 53 is formed on the second surface of the semiconductor body 51 (the upper surface of the semiconductor body 51 in FIG. 2 and corresponding to the surface of the semiconductor body 51 described later). The semiconductor body 51 is a semiconductor layer formed of a semiconductor such as Si.

  The first metal film 52 is formed on the first surface of the semiconductor body 51 (the lower surface of the semiconductor body 51 in FIG. 2). The first metal film 52 includes a base bonding layer 52a and a bonding layer 52b in order from the first surface of the semiconductor body 51 downward. The base bonding layer 52a is formed as a base of the bonding layer 52b. Both the base bonding layer 52a and the bonding layer 52b are formed of a metal material having a melting point higher than that of solder. Further, the first metal film 52 is heated by absorbing a part of the laser light L having a predetermined near infrared wavelength, and may be in a solid phase state (described later) or melted to be in a liquid phase state. Is possible. Specifically, the first metal film 52 is formed of a material that reflects part of the first metal film 52 and absorbs the other part while hardly transmitting the laser light L. In addition, the energy of the laser beam absorbed becomes large, so that the energy density of the laser beam L irradiated to the 1st metal film 52 is large. The first metal film 52 is electronically coupled to the lower surface (second surface) of the semiconductor body 51.

  The second metal film 53 includes a base electrode layer 53b and an electrode layer 53a in order from the second surface of the semiconductor body 51 upward in FIG. The base electrode layer 53b is formed as a base of the electrode layer 53a. In the present embodiment, the base electrode layer 53 b and the electrode layer 53 a are formed of the same material as the base bonding layer 52 a and the bonding layer 52 b of the first metal film 52. The second metal film 53 is electronically coupled to the surface of the semiconductor body 51.

  From the above, in the second metal film 53 and the first metal film 52, the electrode layer 53a and the bonding layer 52b are electronically coupled to the surfaces of the base electrode layer 53b and the base bonding layer 52a, respectively. That is, the lower surface of the base electrode layer 53b in FIG. 2 is electronically coupled to the semiconductor body 51, and the upper surface of the base bonding layer 52a in FIG. 2 is electronically coupled to the semiconductor body 51. .

  The heat spreader 60 is a metal member formed of Cu, for example. The heat spreader 60 is formed separately from the semiconductor component 50 and is disposed in contact with the lower side of the first metal film 52 provided in the semiconductor component 50 in FIG. As shown in FIGS. 2 and 3, the heat spreader 60 includes a facing surface 61, a plurality of convex portions 63, and a reflecting portion 40. The reflection unit 40 is a constituent member of the bonding apparatus 10.

  At the time of joining, the facing surface 61 is opposed to the first metal film 52 with a predetermined distance h2, and the laser light passage region P (see the two-dot chain line reference) between the facing surface 61 and the first metal film 52. ). An opening 65 that opens outward is formed on the outer periphery of the laser beam passage region P.

  As shown in FIGS. 2 and 3, the plurality of convex portions 63 protrude in an island shape from the facing surface 61, and the tip portions are in contact with the first metal film 52. In addition, island shape means the state in which the some convex part 63 has a predetermined clearance gap between the adjacent convex parts 63, and is each independently arrange | positioned on the opposing surface 61. FIG. However, the “island shape” only needs to have a predetermined gap between the adjacent convex portions 63, and includes a state in which the convex portions 63 are arranged in contact with each other.

  As shown in FIGS. 2 and 3, the convex portion 63 is formed in a frustum shape in which the apex side of the quadrangular pyramid is cut parallel to the bottom surface of the quadrangular pyramid. The convex portion 63 is formed such that the first bottom surface 63 a in contact with the facing surface 61 of the heat spreader 60 (metal member) has a larger area than the second bottom surface 63 b in contact with the first metal film 52. Actually, the first bottom surface 63 a of the convex portion 63 is formed integrally with the facing surface 61. The convex portion 63 has a frustum shape based on a quadrangular pyramid. However, it is not limited to this aspect. The convex portion 63 may have a truncated pyramid shape based on a triangular pyramid or another pyramid. Further, the convex portion 63 may have a frustum shape based on another cone.

  The reflection part 40 is arranged on the outer peripheral part of the heat spreader 60 so as to be opposed to the opening part 65 outside the opening part 65 of the laser beam passage region P. The reflection unit 40 includes a reflection surface 40 a on the side facing the opening 65. The reflection surface 40 a is formed with a predetermined angle with respect to the opening 65. The reflection surface 40a of the reflection unit 40 opens the reflected laser light L while partially reflecting the laser light L emitted from the laser head 30 (irradiation angle changing device of the present invention) and absorbing the other part. This is the part that enters the portion 65.

  The heat spreader 60 is coupled to the semiconductor component 50 by joining the second bottom surface 63 b (contact surface) of the convex portion 63 and the contact surface of the first metal film 52. That is, the heat spreader 60 is joined to the first surface of the semiconductor body 51 via the first metal film 52. The heat spreader 60 has a mass of a predetermined capacity and has a function of releasing the heated heat of the semiconductor component 50 through the first metal film 52 and the second bottom surface 63 b of the convex portion 63. Compared with the case where the solder is interposed between the first metal film 52 and the heat spreader 60 as a bonding agent as in the prior art, the bonding speed of the heat is greatly increased. Can be fast.

  Thereby, the heat generated in the semiconductor component 50 cannot escape toward the heat spreader 60 through the bonded contact surface, and the heat is stored in the semiconductor component 50 and does not become high temperature. For this reason, before the semiconductor component 50 reaches a high temperature, the heat immediately flows to the heat spreader 60 side through the bonded contact surface, and the heat spreader 60 radiates heat well. Accordingly, since the temperature of the heat spreader 60 does not rise, for example, the cooling of the heat spreader 60 that has been water-cooled until now can be changed to air-cooling. Further, since the heat capacity of the heat spreader 60 can be reduced, the heat spreader 60 can be downsized.

  In the semiconductor component 50, an unillustrated lead frame is disposed in contact with the upper surface of the second metal film 53 in FIG. The lead frame is a metal member formed of Cu, for example. The lead frame is formed separately from the semiconductor component 50. The lead frame is joined to the semiconductor component 50 so as to be electrically conductive. That is, the lead frame is bonded to the second surface of the semiconductor body 51 through the second metal film 53. The lead frame is a wiring member that supplies power to the semiconductor component 50. The semiconductor body 51 and the lead frame may be joined using any method. As an example, the lead frame and the semiconductor component 50 may be joined by welding using another joining material having a melting point higher than that of solder.

(2. Configuration of the joining apparatus 10)
As shown in FIG. 1, the bonding apparatus 10 includes a laser oscillator 20, a laser head 30, a reflection unit 40, a housing 70, and a control device 80. The laser head 30 and the reflection unit 40 are disposed in the housing 70. As described above, the reflection portion 40 is a part of the heat spreader 60 (metal material).

  The laser oscillator 20 generates laser light by oscillating so that the wavelength becomes a predetermined near infrared wavelength set in advance. At this time, when the material of the base bonding layer 52a of the first metal film 52 is Ti / Ni and the material of the bonding layer 52b is Au as an example, the predetermined near infrared wavelength of the laser light L is 1 It may be around 0.0 μm. Since the near-infrared wavelength of the laser beam L is in the range of about 1.0 μm, the laser beam L is exposed in the laser beam passage region P, and the metal exposed surface of the convex portion 63. Is partially reflected by the exposed metal surface. The laser beam L reflected from the exposed metal surface is repeatedly reflected a plurality of times while irradiating the other exposed metal surface within the laser beam passage region P. In addition, the laser beam L other than the reflected laser beam L is absorbed by the irradiated metal exposed surface, and the first metal film 52 or each convex portion 63 (heat spreader 60) that forms the metal exposed surface. Increase the temperature. This temperature increase rate can be controlled by increasing the output of the laser light L or increasing the irradiation time of the laser light L.

  In the present embodiment, the contact surfaces of the first metal film 52 and the convex portions 63 are formed at a temperature lower than the liquid phase that is in a molten state by irradiation with the laser light L, and are in a solid state. The temperature is raised until a solid state is obtained in which bonding (known solid phase diffusion bonding) is possible. As described above, the temperature of the contact surface is increased by the movement of heat from the first metal film 52 that is heated by absorption of the laser beam L in the other part of the laser beam L and the projections 63. . As an example, the solid phase state can be obtained even at about 200 degrees Celsius. At this time, the irradiation conditions of the laser beam L are set based on prior experiments.

  Specific examples of the laser light L include HoYAG (wavelength: about 1.5 μm), YVO (yttrium vanadate, wavelength: about 1.06 μm), Yb (ytterbium, wavelength: about 1.09 μm), fiber laser, and the like. Adopted. The laser oscillator 20 includes an optical fiber 22 that transmits the laser light L oscillated from the laser oscillator 20 to the laser head 30.

  As shown in FIG. 4A, the laser head 30 is disposed at a predetermined distance from the second metal film 53 of the semiconductor component 50 and facing the second metal film 53. The laser head 30 can change the irradiation angle of the laser light L oscillated from the laser oscillator 20. FIG. 4A illustrates a case where the bonding apparatus 10 is used and the first metal film 52 is first irradiated after the laser beam L is incident on the opening 65.

  In FIG. 4A, the upper side is the upper side and the lower side is the lower side. In addition, as a premise of the configuration of the bonding apparatus 10, the semiconductor component 50 has, for example, a prismatic shape with a square bottom surface, and the length of one side of the bottom surface is D1. Further, the thickness of the semiconductor component 50 including the first metal film 52 is assumed to be t. Further, the height (predetermined distance) from the upper surface of the second metal film 53 to the irradiation center position C of the laser beam L in the laser head 30 (irradiation angle changing device) is set to h3.

  As shown in FIG. 1, the laser head 30 includes a collimating lens 32, a mirror 34, a galvano scanner 36, and an fθ lens 38. As described above, the collimating lens 32, the mirror 34, the galvano scanner 36, and the fθ lens 38 are disposed in the housing 70. The collimating lens 32 collimates the laser light L emitted from the optical fiber 22 and converts it into parallel light.

  The mirror 34 changes the traveling direction of the laser light L so that the collimated laser light L enters the galvano scanner 36. In the present embodiment, the mirror 34 converts the traveling direction of the laser light L by 90 degrees.

  The galvano scanner 36 changes the traveling direction of the laser beam L, and the calculated position of the laser beam L on the reflecting surface 40a of the reflecting unit 40 facing the opening 65 shown in FIG. Irradiate. As the galvano scanner 36, for example, a known scanner including a pair of movable mirrors (not shown) capable of swinging in two orthogonal directions is used.

  The fθ lens 38 is a lens that condenses the parallel laser light L incident from the galvano scanner 36. 4A, the irradiation angle θ of the laser light L is an angle toward an arbitrary position on the outer side (outer diameter side) from the second metal film 53, and specifically, the reflection unit 40 described above. The angle toward the reflecting surface 40a.

  As shown in FIG. 4B, the reflecting portion 40 is opposed to the direction orthogonal to the opening 65 with a preset angle γ, and is arranged so as to continuously surround the outer peripheral surface of the opening 65. Is done. In other words, the angle γ is an angle formed by the horizontal line perpendicular to the vertical line VL1 extending in the vertical direction in FIG.

  Further, the irradiation angle of the laser light L from the laser head 30 is assumed to be θ. Note that the irradiation angle θ is an angle between the perpendicular line VL1 hanging from the irradiation center position C of the laser light L of the laser head 30 and the central axis of the optical path of the laser light L. Further, the height from the first metal film 52 to the reflection position of the laser beam L on the reflection surface 40a of the reflection unit 40 is the reflection position height h1, and the reflection position of the laser beam L on the reflection surface 40a of the reflection unit 40 from the perpendicular line VL1. Is the horizontal distance r. Further, the distance between the first metal film 52 and the facing surface 61 is a distance h2. Note that the vertical width of the opening 65 in FIG. 4A is equal to the distance h2.

  Further, as shown in FIG. 4B, the reflection angle of the laser beam L irradiated from the laser head 30 and reflected by the reflecting surface 40a of the reflecting portion 40 is β, and the laser beam L reflected by the reflecting surface 40a is compared with the horizontal beam in FIG. 4B. Let α be the angle between the (left and right) line. The laser beam L irradiated from the laser head 30 and reflected from the reflecting surface 40a is incident on the opening 65, and the laser beam L reflected from the point p1 irradiated to the lower surface of the first metal film 52 and the reflecting surface 40a of the reflecting unit 40 is reflected. A horizontal distance from the reflection position of the light L is L1, and an angle formed between the lower surface of the first metal film 52 and the laser light L reflected from the lower surface of the first metal film 52 is α. Further, the horizontal (left / right) direction distance from the point p1 where the laser beam L incident on the opening 65 is reflected on the lower surface of the first metal film 52 to the point p2 reflected on the opposing surface 61 next is the horizontal distance. Let w1.

  As described above, the laser beam L emitted from the laser head 30 is reflected by the reflecting surface 40a of the reflecting unit 40, enters the opening 65, and then is reflected by the lower surface of the first metal film 52 to pass the laser beam. When moving in the region P, the following formulas (1) to (6) are established.

(Equation 1)
α = tan ⁻¹ (h2 / w1)
α: angle between the laser beam L reflecting the reflecting surface 40a and the horizontal line h2; distance between the first metal film 52 and the opposing surface 61 w1; after the laser beam L is incident on the opening 65, the first metal film 52 The horizontal distance from the bottom surface of the light beam to the next reflected surface 61

(Equation 2)
α + β = tan ⁻¹ (h / r)
β: Reflection angle of the laser beam L reflecting off the reflecting surface 40a h: Reflection position of the laser beam L on the reflecting surface 40a and height to the irradiation center position C of the laser beam L on the laser head 30 (irradiation angle changing device) ( distance)
r: horizontal distance from the vertical line VL1 to the reflection position of the laser beam L on the reflection surface 40a.

(Equation 3)
γ = (180−β) / 2−α
γ: Angle formed by the horizontal line orthogonal to the perpendicular line VL1 and the reflection surface 40a of the reflection unit 40 facing the outer peripheral surface of the opening 65

(Equation 4)
θ ≧ tan ⁻¹ ((D1 / 2) / h3)
θ: irradiation angle of the laser beam L from the laser head 30 D1; length of one side h3 of the semiconductor component 50; irradiation center position of the laser beam L in the upper surface of the second metal film 53 and the laser head 30 (irradiation angle changing device) Height to C (distance)

(Equation 5)
r = h × tan θ
(Equation 6)
(R− (D1 / 2)) <L1 = h1 / tanα
L1; a position where the laser beam L reflected from the reflecting surface 40a is incident from the opening 65 and irradiated to the lower surface of the first metal film 52 and a reflecting position of the laser beam L reflecting the reflecting surface 40a of the reflecting unit 40 Horizontal distance
h1: Height from the lower surface of the first metal film 52 to the reflection position of the laser beam L on the reflection surface 40a of the reflection portion 40

  When the semiconductor device 50 and the heat spreader 60 are joined, the control device 80 shown in FIG. 1 determines the position of the laser head 30 and the irradiation angle of the laser light L emitted from the laser head 30. And it calculates from the shape of the heat spreader 60 in advance. Then, the control device 80 controls the position of the laser head 30 and the irradiation angle based on the calculation result. Specifically, the control device 80 inputs basic information (D1, t, etc.) of the semiconductor component 50 and the heat spreader 60, and thereby the irradiation center position of the laser light L in the laser head 30 from the upper surface of the second metal film 53. The height h3 (distance) to C is calculated. In addition, the control device 80 operates a driving device (not shown) to move the irradiation center position C of the laser head 30 to the calculated height h3. Further, the control device 80 calculates the irradiation angle θ of the laser light L from the laser head 30 and controls the irradiation angle so that the irradiation can be performed in the calculated direction.

The control device 80 includes a basic information storage unit 81, a distance calculation unit 82, an irradiation angle calculation unit 83, an irradiation angle change device movement control unit 84, and an irradiation angle change control unit 85.
The basic information storage unit 81 stores basic information that is each position and each shape of the input semiconductor component 50, the opening 65, and the reflection unit 40. The basic information may be input by an operator from an input unit (not shown) by his / her own hand. The basic information may be obtained by reading the semiconductor component 50 and the heat spreader 60 with an imaging device arranged at a predetermined position and reading various dimension data from the acquired image. At this time, as an example of the input data, for example, the length D1 of one side of the semiconductor component 50 formed in a square (rectangular shape), the thickness t of the semiconductor component 50, the relative position of the reflecting portion 40 with respect to the opening 65, The inclination γ of the reflecting surface 40a of the reflecting portion 40, the vertical width (= distance h2) of the opening 65 in FIG. In addition, each calculation in the distance calculation part 82 and the irradiation angle calculation part 83 demonstrated below is performed based on the (Formula 1) Formula-(Formula 6) mentioned above.

  The distance calculation unit 82 extends from the second metal film 53 to the irradiation center position C of the laser head 30 (irradiation angle changing device) so that the laser light L reflected by the reflection unit 40 can enter the opening 65. Is calculated based on the basic information. The height h3 is, for example, a median value within a range in which the laser beam L can be incident on the opening 65.

  When it is assumed that the laser head 30 is arranged at a height h3 from the second metal film 53, the irradiation angle calculation unit 83 opens the laser light L reflected by the reflection surface 40a of the reflection unit 40. Based on the basic information, the laser head 30 calculates the irradiation angle θ of the laser light L that should be irradiated toward the reflection unit 40 so that the laser beam can enter the unit 65. At this time, the irradiation angle θ is, for example, an angle at which the laser beam L reflected by the reflecting surface 40 a is incident from the opening 65 and is irradiated to an arbitrary position near the opening 65 on the lower surface of the first metal film 52. And Thereby, a larger number of reflections can be expected with respect to the exposed metal surface in the laser beam passage region P. In addition, although the distance calculation part 82 and the irradiation angle calculation part were described separately, actually, it calculates simultaneously, exchanging a result.

The irradiation angle changing device movement control unit 84 operates a driving device (not shown) to move the laser head 30 so that the laser head 30 is disposed at a position where the height h3 is reached.
The irradiation angle change control unit 85 changes the setting of the irradiation angle of the laser head 30 so that the laser light L is emitted at the calculated irradiation angle θ.

(3. Joining method)
Next, the joining method of the joining apparatus 10 is demonstrated based on the flowchart of FIG. 4A, FIG. 4B, and FIG. As shown in FIG. 5, the bonding method includes an incident step S10, a temperature raising step S12, and a bonding step S14.

  First, the operation of the control device 80 that is activated first will be briefly described. For example, it is assumed that the worker starts joining of a semiconductor component and a heat spreader other than the semiconductor component and the heat spreader that have been joined so far.

  In this case, the worker first inputs the basic information (such as the relative positional relationship such as D1, t) of the semiconductor component to be joined and the heat spreader to the basic information storage unit 81 of the control device 80. Next, the distance calculation unit 82 calculates the height h3 from the second metal film 53 to the irradiation center position C of the laser head 30 (irradiation angle changing device) based on the basic information. In addition, when the laser head 30 is disposed at the height h3 by the irradiation angle calculation unit 83, the laser head L can be incident on the opening 65 so that the laser light L reflected by the reflection surface 40a of the reflection unit 40 can enter. The irradiation angle θ of the laser light L that 30 irradiates toward the reflecting portion 40 is calculated based on the basic information.

  Then, the driving device (not shown) is operated and moved by the irradiation angle changing device movement control unit 84 so that the laser head 30 is disposed at the calculated height h3. Further, the irradiation angle change control unit 85 changes the setting of the irradiation angle of the laser head 30 so that the laser light L is emitted at the calculated irradiation angle θ. In this way, operations other than the input of basic information are automatically performed.

  In the incident step S10, first, the laser oscillator 20 is driven to oscillate the laser light L at a predetermined near infrared wavelength. As described above, at this time, the predetermined near-infrared wavelength of the laser light L is about 1.0 μm. The laser light L oscillated from the laser oscillator 20 is incident on the optical fiber 22 and transmitted to the laser head 30 (see FIG. 1).

  The laser light L emitted from the optical fiber 22 is collimated by the collimator lens 32, reflected by the mirror 34, passes through the galvano scanner 36, and is irradiated toward the reflection unit 40 through the fθ lens 38. At this time, the galvano scanner 36 changes the angle of the laser light L incident on the fθ lens 38 by swinging a pair of orthogonal movable mirrors (not shown). The angle of the laser beam L to be changed is based on the command value from the irradiation angle change control unit 85 as described above.

  As a result, the laser light L is irradiated to a predetermined position on the opening 65 side of the reflection part 40 formed on the heat spreader 60 described above via the fθ lens 38, and a part of the laser light L is reflected by the reflection part 40. Then, the reflected laser beam L enters the laser beam passage region P from the opening 65 (see FIGS. 4A and 4B).

  In the temperature raising step S12, the other part of the laser beam L is absorbed each time while a part of the laser beam L is reflected a plurality of times on the exposed metal surface in the laser beam passage region P. The metal exposed surface mainly refers to a part of the facing surface 61 of the heat spreader 60, the side surface of the convex portion 63, and the lower surface of the first metal film 52 that are exposed in the laser beam passage region P.

  By such irradiation to the exposed metal surface, the other part of the laser beam L is absorbed from the exposed metal surface. Thereby, the temperature of the convex portion 63 and the first metal film 52 is gradually raised, and the contact surface between the second bottom surface 63b and the first metal film 52 which is the tip portion of the convex portion 63 is also heated by the movement of heat. . Each contact surface is thus heated up and melted to form a liquid phase state, which is established at a lower temperature, and a solid phase state in which the contact surfaces can be joined in a solid state. At this time, whether or not it is in the solid phase state may be managed by acquiring the time until the solid phase state is obtained by a prior experiment.

  In joining process S14, each contact surface of the 2nd bottom face 63b of the convex part 63 used as the solid-phase state and the 1st metal film 52 is pressurized in the direction to join (refer FIG. 4A). At this time, the pressurizing pressure may be set by a prior experiment. Moreover, the pressurization method is not ask | required. As long as the semiconductor component 50 is not broken, the pressure may be applied by any method. Thereby, the 2nd bottom face 63b of the convex part 63 and the 1st metal film 52 are joined by solid phase diffusion joining. For this reason, since the 2nd bottom face 63b of the convex part 63 and the 1st metal film 52 can be joined without soldering, high heat resistance is acquired with respect to joining of a contact surface. Solid phase diffusion bonding is a known technique in which free electrons move between the surfaces of two metals in contact with each other to generate a bonding force and bond them. Thus, since it is well-known, detailed description is abbreviate | omitted.

  In the above embodiment, when the second bottom surface 63b of the convex portion 63 and the first metal film 52 are joined, the pressure is applied in the joining direction. However, it is not limited to this aspect. By further improving the surface roughness of each contact surface of the second bottom surface 63b and the first metal film 52 and having a mirror finish, there is a case where both can be joined without applying pressure. There is no need.

  In the description of the above process, only one irradiation with one laser beam L has been described for convenience of description. However, actually, in the incident step S10, the galvano scanner 36 intermittently irradiates the laser beam L while moving a pair of orthogonal movable mirrors in the rotation direction with respect to the vertical line VL1. That is, the flowchart shown in FIG. 5 is repeatedly executed. Thereby, the temperature of the convex part 63 is uniformly increased, and a good bonding state with the first metal film 52 is obtained.

  In the above description, the irradiation with the laser beam L may be a so-called pulse laser that irradiates the laser beam L intermittently. Further, the laser light L may be continuously irradiated by a CW laser (Continuous wave laser) which is not irradiated intermittently and whose energy control is easy.

(4. Effects of the embodiment)
According to the said embodiment, the semiconductor component 50 provided with the 1st metal membrane | film | coat 52 formed in the semiconductor body 51 and the 1st surface of a semiconductor body, and the semiconductor component 50 and a 1st metal membrane | film | coat are formed separately. 52, a heat spreader 60 (metal member) disposed in contact with 52 by a laser beam L. The heat spreader 60 is opposed to the first metal film 52 with a distance therebetween, and A counter surface 61 that forms a laser beam passage region P with the one metal film 52, and a plurality of protrusions 63 that protrude from the counter surface 61 in an island shape and whose tip portion contacts the first metal film 52. An opening 65 that opens outward is formed on the outer periphery of the laser beam passage region P, and the bonding apparatus 10 makes the laser beam L incident on the laser beam passage region P through the opening 65 and passes the laser beam. The metal exposed surface in the region P absorbs the other part of the laser beam L while reflecting a part of the laser beam a plurality of times, and melts each contact surface between the first metal film 52 and the tip of the projection 63. Bonding is performed by raising the temperature until a solid phase state is established at a temperature lower than the liquid phase state, which is in a state where it can be joined in a solid state.

  According to this, the heat raised in the first metal film 52 and the convex part 63 due to the absorption of the other part of the laser light L is between the first metal film 52 and the convex part 63 via the contact surface. It moves from the higher temperature side to the lower side, and at the same time the temperature of the contact surface is increased. And when the temperature of a contact surface will be in a solid-phase state, each contact surface will be joined by solid-phase diffusion bonding. Thereby, since contact surfaces are joined without using solder, heat resistance improves compared with the case where each contact surface is joined by solder. As a result, even if the semiconductor component becomes high temperature during use, the reliability of bonding of the contact surfaces between the semiconductor component and the metal member is ensured.

  Moreover, according to the said embodiment, when joining each contact surface of the 1st metal membrane | film | coat 52 and the front-end | tip part of the convex part 63, the joining apparatus 10 pressurizes in the direction which joins each contact surface. Thereby, even if the surface roughness is rough, the 1st metal film 52 and the convex part 63 can be joined reliably.

  Moreover, according to the said embodiment, the convex part 63 has the 1st bottom face 63a integrally formed in the opposing surface 61 with which the heat spreader 60 (metal member) is equipped from the 2nd bottom face 63b which contact | connects the 1st metal film 52. It is formed in a frustum shape having a large area. Thereby, since the laser beam L freely passes through the laser beam passage region P and the contact area with the first metal coating 52 can be sufficiently secured by the second bottom surface 63b, the convex portion 63 and the first metal coating 52 are secured. It is possible to achieve both a strong bonding with and.

  Further, according to the above embodiment, the bonding apparatus 10 includes the laser oscillator 20 that oscillates the laser light L (corresponding to an oscillation source) and the second metal provided on the semiconductor component 50 on the opposite side of the first metal film 52. The irradiation angle of the laser beam L, which is disposed at a distance from the coating 53 and is opposed to the second metal coating 53, is changed, and the laser beam L is applied to an arbitrary position outside the semiconductor component. An irradiating laser head 30 (irradiation angle changing device) is arranged outside the opening 65 in the laser beam passage region P so as to face the opening 65, and reflects the laser beam L emitted from the laser head 30. And a reflecting portion 40 that is incident on the opening 65. Thereby, the semiconductor component 50 and the heat spreader 60 (metal member) can be simply joined by simply setting the semiconductor component 50 and the heat spreader 60 (metal member) at a predetermined position and starting the joining device.

  Moreover, according to the said embodiment, the reflection part 40 is formed in the heat spreader 60 (metal member). Accordingly, it is not necessary to separately manufacture the reflective portion and fix it to the housing 70, so that an operation such as matching the relative positions of the reflective portion and the opening 65 is unnecessary, and the operation becomes easy. This also contributes to cost reduction.

  Moreover, according to the said embodiment, the joining apparatus 10 is provided with the control apparatus 80, and the control apparatus 80 is the basic information which is each position and each shape of the semiconductor component 50, the opening part 65, and the reflection part 40 which are input. The height from the second metal film 53 for allowing the laser beam L reflected by the reflecting unit 40 to be incident on the opening 65 to the laser head 30 (irradiation angle changing device). In order to allow the laser beam L reflected by the reflecting unit 40 to be incident on the opening 65 when the distance calculating unit 82 that calculates h3 based on the basic information and the laser head 30 at the height h3 are arranged, a laser is used. An irradiation angle calculation unit 83 that calculates the irradiation angle θ of the laser light L emitted from the head 30 toward the reflection unit 40 based on the basic information, and the laser head 30 are arranged so as to be arranged at the calculated height h3. An irradiation angle changing device movement control unit 84 for moving the head 30, and an irradiation angle changing control unit 85 for changing the setting of the irradiation angle of the laser head 30 so that the laser beam L is irradiated at the calculated irradiation angle θ. Prepare. As a result, a joined body of the semiconductor component 50 having heat resistance at the joint portion and the heat spreader 60 (metal member) is obtained.

  Further, according to the embodiment, the bonding apparatus 10 includes the semiconductor body 51 and the semiconductor component 50 including the first metal film 52 formed on the first surface of the semiconductor body 51, and the semiconductor component 50. The heat spreader 60 (metal member) formed in contact with the first metal film 52 and bonded to the first metal film 52 by a laser beam L, the heat spreader 60 being a distance from the first metal film 52. Are opposed to each other and form a laser beam passage region P between the first metal film 52 and a plurality of islands projecting from the opposed surface 61 in an island shape and having tip portions in contact with the first metal film 52. And an opening 65 that opens outward is formed on the outer periphery of the laser beam passage region P. The bonding method includes an incident step S10 in which the laser beam L is incident on the laser beam passage region P from the opening 65, and a part of the incident laser beam L is reflected a plurality of times at the exposed metal surface in the laser beam passage region P. The other portion of the laser beam L is absorbed while the contact surfaces of the first metal film 52 and the tip of the convex portion 63 are formed at a temperature lower than the liquid phase state and can be joined in a solid state. There are provided a temperature raising step S12 for raising the temperature until the phase state is reached, and a joining step S14 for joining the contact surfaces that are in the solid phase by the temperature raising step S12. Thereby, the joining of the semiconductor component 50 and the heat spreader 60 obtained by the joining apparatus 10 is obtained.

  According to the bonding method of the above embodiment, in the bonding step S14, when the contact surfaces are bonded, pressure is applied in the direction in which the contact surfaces are bonded. Thereby, each contact surface can be reliably joined even if the surface roughness is rough.

<Deformation mode>
In the embodiment described above, the reflecting portion 40 is formed integrally with the heat spreader 60 (metal member). However, the present invention is not limited to this aspect, and the reflecting portion 40 may be formed separately from the heat spreader 60. In this case, the reflection part 40 should just be fixed to the internal peripheral surface of the housing | casing 70 (not shown).

  In the above embodiment, the reflecting surface 40 a of the reflecting portion 40 is formed with a predetermined angle with respect to the opening 65. However, the present invention is not limited to this mode, and the reflecting surface 40a may be formed in parallel with the opening 65 as shown in FIG. In this case, as shown in FIG. 6, the laser beam L reflected by the reflecting surface 40a is once irradiated on the opposing surface 61 of the heat spreader 60 (metal member) formed outside the opening 65 and then reflected. Then, the light may enter the opening 65. This also provides the same effect.

  2 and 3, according to the above-described embodiment and modification, the convex portion 63 has a first bottom surface 63a on the facing surface 61 side of the heat spreader 60 (metal member). 52 is formed in a frustum shape having an area larger than that of the second bottom surface 63 b in contact with 52. However, it is not limited to this aspect. Any shape may be used as long as it has a predetermined gap between the adjacent convex portions 63 and the laser beam L can move in the laser beam passage region P. For example, the gap between the convex portions 63 may be parallel in the vertical direction. A corresponding effect can be expected also by this.

  Moreover, in the said embodiment and the deformation | transformation aspect, although the convex part 63 and the 1st metal membrane | film | coat 52 of the heat spreader 60 were joined by the solid phase diffusion bond, it is not restricted to this aspect. In the temperature raising step S12, the temperature is raised until each contact surface between the second bottom surface 63b, which is the tip of the convex portion 63, and the first metal film 52 is melted, and the liquid phase is the same as in conventional welding. The heat spreader 60 and the first metal film 52 may be joined in a state. As a result, although it takes time until the temperature rises, the same effect can be expected.

  Moreover, in the said embodiment and the deformation | transformation aspect, it was supposed that the laser beam L was the laser beam L which has a near-infrared wavelength. However, the present invention is not limited to this, and the laser light L may be a blue laser.

  Moreover, in the said embodiment and modification, the joining apparatus 10 is provided with the control apparatus 80, and even if it inserts into a joining apparatus 10 the semiconductor component and heat spreader from which size differs, it joins a semiconductor component and a heat spreader favorably. It explained as a general-purpose machine that can. However, it is not limited to this aspect. The joining apparatus 10 may be a dedicated machine that does not include the control device 80 and that joins only one type of semiconductor component 50 and the heat spreader 60.

  Moreover, in the said embodiment and a deformation | transformation aspect, when the laser beam L is reflected in the laser beam passage area | region P, the convex part 63 which the heat spreader 60 (metal member) has, and the 1st metal film of the semiconductor component 50 It has been explained that it moves while reciprocally reflecting between 52 and 52. However, it is not limited to this aspect. The laser beam L may move while reflecting only between the convex portion 63 of the heat spreader 60 (metal member) and the opposing surface 61 or between the plurality of convex portions 63, and only raise the temperature of the convex portion 63. . Also by this, as long as time is required, heat is transferred from the convex portion 63 to the contact surface and the temperature is raised, so that the joining can be performed.

  DESCRIPTION OF SYMBOLS 10 ... Joining device, 20 ... Laser oscillator (oscillation source), 30 ... Laser head (irradiation angle changing device), 40 ... Reflecting part, 40a ... Reflecting surface, 50 ... Semiconductor Components: 51 ... Semiconductor body 52 ... First metal film 53 ... Second metal film 60 ... Heat spreader (metal member) 61 ... Opposite surface 63 ... Projection 63a ... First bottom surface, 63b ... Second bottom surface, 65 ... Opening, 70 ... Housing, 80 ... Control device, 81 ... Basic information storage unit, 82 ... -Distance calculator, 83 ... Irradiation angle calculator, 84 ... Irradiation angle change device movement controller, 85 ... Irradiation angle change controller, C ... Irradiation center position, h1 ... Reflection position Height, h2 ... Distance, h3 ... Height, L ... Z light, P: laser beam passing region, S10: incident process, S12: temperature raising process, S14: bonding process, VL1: perpendicular, θ: irradiation angle.

Claims (8)

A semiconductor component comprising a semiconductor body and a first metal film formed on a first surface of the semiconductor body;
A metal member formed separately from the semiconductor component and disposed in contact with the first metal film;
Is a joining device for joining with laser light,
The metal member is
Opposing the first metal film at a distance and facing the first metal film to form a laser light passage region with the first metal film,
A plurality of convex portions protruding in an island shape from the facing surface, the tip portion contacting the first metal film,
With
On the outer periphery of the laser beam passage region, an opening that opens outward is formed,
The joining device includes:
The laser beam is incident on the laser beam passage region from the opening,
Absorbing the other part of the laser beam while reflecting a part of the laser beam multiple times at the exposed metal surface in the laser beam passage region,
Each contact surface between the first metal film and the tip of the convex portion is in a liquid state that is in a molten state or a solid state that can be joined in a solid state at a temperature lower than the liquid phase state. An apparatus for joining a semiconductor component and a metal member, which is heated and joined to a phase state.   2. The semiconductor component and the metal member according to claim 1, wherein when the contact surfaces of the first metal film and the tip of the convex portion are joined, the contact surfaces are pressed in the joining direction. Joining equipment.   The said convex part is formed in the frustum shape in which the 1st bottom face which contact | connects the said opposing surface of the said metal member has a larger area than the 2nd bottom face which contact | connects said 1st metal membrane | film | coat. Joining device for semiconductor parts and metal members. The joining device includes:
An oscillation source for oscillating the laser beam;
Irradiation of the laser light oscillated from the oscillation source, arranged at a distance from the second metal film provided on the opposite side of the first metal film in the semiconductor component and opposed to the second metal film An irradiation angle changing device capable of changing the angle and irradiating the laser beam to any position outside the semiconductor component;
A reflection part that is arranged outside the opening part of the laser light passage region so as to be opposed to the opening part and reflects the laser light emitted from the irradiation angle changing device and makes it incident on the opening part;
The joining apparatus of the semiconductor component and metal member of any one of Claims 1-3 provided with these.   The said reflection part is a bonding | joining apparatus of the semiconductor component and metal member of Claim 4 formed in the said metal member. The joining device includes a control device,
The controller is
A basic information storage unit that stores basic information that is each position and each shape of the semiconductor component, the opening, and the reflection unit that are input;
A distance calculation unit for calculating an optimum distance from the second metal film to the irradiation angle changing device for allowing the laser beam reflected by the reflection unit to enter the opening, based on the basic information;
When the irradiation angle changing device is disposed at the optimum distance, the irradiation angle changing device irradiates the reflecting portion so that the laser beam reflected by the reflecting portion can enter the opening. An irradiation angle calculation unit for calculating an optimum irradiation angle of the laser light based on the basic information;
An irradiation angle changing device movement control unit for moving the irradiation angle changing device so that the irradiation angle changing device is arranged at the calculated optimum distance;
An irradiation angle change control unit for changing the setting of the irradiation angle of the irradiation angle changing device so that the laser beam is irradiated at the calculated optimal irradiation angle;
The joining apparatus of the semiconductor component and metal member of Claim 5 provided with these. A semiconductor component comprising a semiconductor body and a first metal film formed on a first surface of the semiconductor body;
A metal member formed separately from the semiconductor component and disposed in contact with the first metal film;
Is a joining method for joining with laser light,
The metal member is
Opposing the first metal film at a distance and facing the first metal film to form a laser light passage region with the first metal film,
A plurality of convex portions protruding in an island shape from the facing surface, the tip portion contacting the first metal film,
With
On the outer periphery of the laser beam passage region, an opening that opens outward is formed,
The joining method is:
An incident step of causing the laser beam to enter the laser beam passage region from the opening;
The metal exposed surface in the laser beam passage region absorbs the other part of the laser beam while reflecting a part of the incident laser beam a plurality of times, and the first metal film and the tip of the convex portion A temperature raising step of raising the temperature of each contact surface to a molten phase, or a solid phase that can be joined in a solid state at a temperature lower than the liquid phase,
A bonding step of bonding the contact surfaces in the liquid phase state or the solid phase state by the temperature raising step;
A method for joining a semiconductor component and a metal member.   The method for joining a semiconductor component and a metal member according to claim 7, wherein, in the joining step, when the contact surfaces are joined, the contact surfaces are pressurized in the joining direction.

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