Patent Description:
Semiconductor device packages, or modules, often include elements to mount or otherwise couple the package to a printed circuit board (PCB) or to other elements. Such mounting elements often include electrical contacts, or pins, that are configured to be press-fit into receivers of a PCB/motherboard or other element. Press-fit pins serve to establish solderless electrical connections by introducing the pins into corresponding bores of a carrier, the bore having a smaller diameter than the pin. In some approaches, the bore may be lined with a conductive material.

<CIT> refers to electrical connectors provided with pairs of prongs either of identical shape or mirror images when facing the outer ends of interengageable pairs.

The present invention is defined in the independent claim <NUM>.

Furthermore, certain elements in some of the figures may be omitted, or illustrated not-to-scale, for illustrative clarity. Furthermore, for clarity, some reference numbers may be omitted in certain drawings.

The present disclosure will now be described more fully hereinafter with reference to the accompanying drawings.

A semiconductor device package is provided which includes improved electrical contacts. As will be described further herein, electrical contacts of the present disclosure may include two or more components coupled together to form a one-body pin. A first, base portion of the pin may be first attached to a substrate, and a second, upper portion of the pin may then be coupled to the first component, e.g., after wire bonding. Each of the components may include a set of prongs, which compliment when the components are coupled together. A gap or slot between the prongs may provide stress relief during the mating process of the first and second components.

Referring now to <FIG>, an electrical contact <NUM> of an assembly <NUM> according to the present disclosure will be described. As shown, the electrical contact <NUM>, sometimes referred to as a pin, may include a first component <NUM> and a second component <NUM> generally aligned end-to-end along a lengthwise axis <NUM>. The electrical contact <NUM> is shown in a connected configuration in <FIG>, and in a separated or disconnected configuration in <FIG>. As will be described in greater detail herein, the first and second components <NUM>, <NUM> may be coupled together after the first component <NUM> has been secured to a substrate (not shown).

The first component <NUM> may include a first end <NUM> opposite a second end <NUM>. The first end <NUM> may include a flared base <NUM> to provide support to the first component <NUM>, and to increase adhesion of the electrical contact <NUM> to a substrate. The second end <NUM> may include a base slot <NUM> formed therein, wherein the base slot <NUM> is defined in part by a first set of members or prongs <NUM>. The prongs <NUM> may include a base <NUM> and a free end <NUM>. The free end <NUM> of the prongs <NUM> may be configured to flex, e.g., radially away and/or towards the lengthwise axis <NUM> to change the width of the base slot <NUM>. The prongs <NUM> may exhibit good spring characteristics. Each of the prongs <NUM> may be connected by a first base wall <NUM>. As shown, the first base wall <NUM> may be a planar surface extending generally perpendicular to the lengthwise axis <NUM>.

The second component <NUM> may include a first end <NUM> opposite a second end <NUM>. The second end <NUM> may include an upper slot <NUM> formed therein, wherein the upper slot <NUM> is defined in part by a second set of members or prongs <NUM>. The prongs <NUM> may include a base <NUM> and a free end <NUM>. The free end <NUM> of the prongs <NUM> may be configured to flex, e.g., radially away and/or towards the lengthwise axis <NUM> to change the width of the upper slot <NUM>. The prongs <NUM> may exhibit good spring characteristics. Each of the prongs <NUM> may be connected by a second base wall <NUM>. As best shown in <FIG>, a thickness 'T' of the first component <NUM> may be substantially the same as a width 'W' of the upper slot <NUM> to ensure proper assembly and support for the first and second components <NUM>, <NUM>.

At the first end <NUM> of the second component <NUM> may be an angled tip <NUM>. As shown in <FIG>, the angled tip <NUM> may include a loop <NUM>. Although non-limiting, the first and second components <NUM>, <NUM> may be same material (e.g., copper or a copper alloy with a Sn surface, galvanically formed, and with an appropriate µm thickness) with a same hardness, thus allowing optimal cold welding and preventing coefficient of thermal expansion (CTE) mismatch during extreme temperatures.

As shown in <FIG>, the first prongs <NUM> and the second prongs <NUM> may engage one another to couple the first and second components <NUM>, <NUM> together. The first component <NUM> demonstrated in <FIG> may be rotated by approximately <NUM> degrees and then lowered onto the second component <NUM> until the first component <NUM> is inserted into the upper slot <NUM> and the second component <NUM> is inserted into the base slot <NUM>. Once engaged, the first base wall <NUM> and the second base wall <NUM> may abut or engage one another to prevent further axial movement of the first component <NUM>. It will be appreciated that the base slot <NUM> and the upper slot <NUM> provide stress relief during the mating process of the first and second components <NUM>, <NUM>.

As shown, the first prongs <NUM> and the second prongs <NUM> extend adjacent one another such that the first prongs <NUM> extend along an exterior surface <NUM> of the second component <NUM>, and the second set of prongs <NUM> extends along an exterior surface <NUM> of the first component <NUM>. The first prongs <NUM> and the second prongs <NUM> may generally be oriented parallel to one another and to the lengthwise axis <NUM>.

As shown in <FIG>, the first component <NUM> may include one or more stress relief trenches <NUM> formed along a bottom surface <NUM> of the flared base <NUM> at the first end <NUM> of the device <NUM>. As shown, the stress relief trenches <NUM> may be formed across a perimeter <NUM> of the bottom surface <NUM>. It will be appreciated that virtually any number or configuration of the stress relief trenches <NUM> may be possible. Advantageously, a footprint (e.g., defined by the area of the bottom surface <NUM> of the flared base <NUM>) may be smaller than prior designs, thus providing additional valuable direct copper bonding (DCB) landing for die and wire bonding. However, specific dimensions of the electrical contact <NUM> may vary according to the application.

The stress relief trenches <NUM> may further increase adhesion between the first component <NUM> and an electrically insulating material <NUM>, as shown in <FIG>. The first component <NUM> is preferably joined to a substrate <NUM> by a solder <NUM>, deposited to the substrate <NUM>, or otherwise secured (e.g., fused, soldered, bonded, or welded) onto a conductive layer <NUM> along a top surface <NUM> of the electrically insulating material (e.g., dielectric material) <NUM>. As shown, the solder <NUM> may enter the stress relief trench <NUM>. A second conductive layer <NUM> can be secured (e.g., fused, soldered, bonded, or welded) to the bottom surface <NUM> of the electrically insulating material <NUM>. The first conductive layer <NUM> can be secured (e.g., bonded, brazed, sintered) to the top surface <NUM> of the electrically insulating material <NUM>. The conductive layer <NUM>, the electrically insulating material <NUM>, and the second conductive layer <NUM> form a complete direct copper bonding (DCB) supporting structure. The electrically insulating material <NUM> may be ceramic and the conductive layers <NUM>, <NUM> may be copper secured (e.g., fused, soldered, bonded, or welded) to opposite sides of the electrically insulating material <NUM> at a high temperature. The electrically insulating material <NUM> may be ceramic and the conductive layers <NUM>, <NUM> may be aluminum secured (e.g., bonded, brazed, sintered) to opposite sides of the electrically insulating material <NUM> at high temperature. The substrate <NUM> may be a copper leadframe. After the first component <NUM> has been secured (e.g., fused, soldered, bonded, or welded) to the electrically insulating material <NUM>, the second component <NUM> may be coupled to the first component <NUM>, e.g., by inserting the second component <NUM> into the base slot <NUM>, as described above.

The substrate <NUM> may include multiple layers. For example, the substrate <NUM> may be a power electronic substrate coupled to a baseplate, which in turn may be coupled to a heat sink or the like. The baseplate may also be omitted, and the substrate <NUM> may be directly coupled to a heat sink or the like. The power electronic substrate may include, by non-limiting example, a direct bonded copper (DBC) substrate, an active metal brazed (AMB) substrate, an insulated metal substrate (IMS), a thick film ceramic substrate, and the like.

Turning now to <FIG>, a method <NUM> according to the present disclosure will be described in greater detail. At block <NUM>, the method <NUM> may include coupling a first component of an electrical contact to a substrate, the first component including a base slot defined by a first set of prongs. The method may include providing a conductive layer over the substrate, and coupling the first component to the conductive layer by a solder.

At block <NUM>, the method <NUM> may further include coupling a second component to the first component, wherein the second component includes an upper slot defined by a second set of prongs, wherein the first set of prongs engage the second set of prongs. The method may further include positioning the first set of prongs and the second set of prongs adjacent one another when the first component and the second component are coupled together, wherein the first set of prongs and the second set of prongs are oriented parallel to a lengthwise axis extending through the first component and the second component.

The method may include inserting the first component within the upper slot, and inserting the second component within the base slot, wherein the first set of prongs extends along an exterior surface of the second component. The second set of prongs may extend along an exterior surface of the first component. Two cooperating stops of the first and second components may block the movement of the first and second components towards each other.

The electrical contact <NUM> described herein may be used with the package <NUM> shown in <FIG>. The package <NUM> may include a housing <NUM> having a main body <NUM> and a wall <NUM> extending around a perimeter of the main body <NUM>. The wall <NUM> may include a pair of end walls 214A, 214B and a pair of sidewalls 216A, 216B. As shown, the pair of end walls 214A, 214B and the pair of sidewalls 216A, 216B extend perpendicularly from the main body <NUM>. Together, the main body <NUM> and the wall <NUM> define an internal cavity (not shown) for housing one or more semiconductor devices.

The main body <NUM> may further include a plurality of terminal openings <NUM> configured to receive the electrical contact(s) <NUM> of the present disclosure. The main body <NUM> and the wall <NUM> define an internal cavity housing one or more semiconductor devices coupled to the substrate <NUM>. The semiconductor devices may include one or more power semiconductor dies, such as one or more power metal-oxide-semiconductor field-effect transistors (power MOSFETs), one or more insulated-gate bipolar transistors (IGBTs), and the like.

The electrical contacts, once coupled to the substrate <NUM>, are configured to extend upwards such as to exit the terminal openings <NUM> in the main body <NUM> when the package <NUM> is lowered towards the substrate <NUM>. The main body <NUM> may be attached to the substrate <NUM> and/or baseplate or otherwise coupled thereto, such as using screws, a friction fit, an adhesive, soldering, and the like. The electrical contacts, which extend upwards through the terminal openings <NUM>, are used to couple the one or more die to one or more power sources, one or more electrical grounds, one or more electrical components external to the package <NUM>, and the like by coupling the electrical contacts to a motherboard, printed circuit board (PCB) or the like. As indicated previously, each electrical contact may be coupled the die using a network of connection traces on a surface of the substrate <NUM>.

Turning now to <FIG>, an electrical contact <NUM> according to the present disclosure will be described. As shown, the electrical contact <NUM>, sometimes referred to as a pin, may include a first component <NUM> and a second component <NUM> generally aligned end-to-end along a lengthwise axis <NUM>. The electrical contact <NUM> is shown in a separated or disconnected configuration, wherein the first and second components <NUM>, <NUM> may be coupled together after the first component <NUM> has been secured to a substrate (not shown).

The first component <NUM> may include a first end <NUM> opposite a second end <NUM>. The first end <NUM> may include a flared base <NUM> to provide support to the first component <NUM>, and to increase adhesion of the electrical contact <NUM> to a substrate, e.g., using a solder <NUM>. The second end <NUM> may include a base slot <NUM> formed therein, wherein the base slot <NUM> is defined in part by a first set of members or prongs <NUM>. The first prongs <NUM> may include a base <NUM> and a free end <NUM>. The free end <NUM> of the first prongs <NUM> may be configured to flex, e.g., radially away and/or towards the lengthwise axis <NUM> to change the width of the base slot <NUM>. Each of the prongs <NUM> may be connected by a first base wall <NUM>, which defines a closed end of the base slot <NUM>.

The second component <NUM> may include a first end <NUM> opposite a second end <NUM>. The second end <NUM> may include an upper slot <NUM> formed therein, wherein the upper slot <NUM> is defined in part by a second set of members or prongs <NUM>. The second prongs <NUM> may include a base <NUM> and a free end <NUM>. Each of the second prongs <NUM> may be connected by a second base wall <NUM>, which defines a closed end of the upper slot <NUM>.

The first component <NUM> includes a first section <NUM>, wherein the first section is circular, and one or more planar surfaces <NUM> extending from the first section <NUM>. The planar surfaces <NUM> abuts an inner surface <NUM> of the second prongs <NUM> when the first and second components <NUM>, <NUM> are brought together. Furthermore, the first section <NUM> includes one or more prong slots <NUM> operable to receive the second prongs <NUM> of the second component <NUM>. Each prong slot <NUM> includes a radial surface <NUM> operable to engage or abut a side surface <NUM> of the second prongs <NUM> Moreover, the planar surface(s) <NUM> in contact with the inner surface <NUM> of the second prongs <NUM> prevents or minimizes movement or pivoting of the second component <NUM> along the z-direction. Meanwhile, the radial surface <NUM> in contact with the side surface <NUM> of the second prongs <NUM> prevents or minimizes movement or pivoting of the second component <NUM> along the x-direction.

<FIG> is a side view of a second component <NUM> of an electrical contact <NUM> according to the present disclosure. The electrical contact <NUM> may be the same or similar in many aspects to the electrical contacts <NUM> and <NUM> described above. As such, only certain aspects of the electrical contact <NUM> will hereinafter be discussed for the sake of brevity.

The second component <NUM> may include a first end <NUM> opposite a second end <NUM>. The second end <NUM> may include an upper slot <NUM> formed therein, wherein the upper slot <NUM> is defined in part by a second set of members or prongs <NUM>. The second prongs <NUM> may include a base <NUM> and a free end <NUM>. Between the base <NUM> and the free end <NUM> may be one or more protrusions <NUM> extending into the upper slot <NUM>. The protrusions <NUM> may provide enhanced gripping towards the middle of the second prongs <NUM> to ensure surface contact between the second component <NUM> and the first component (not shown).

<FIG> demonstrates another electrical contact <NUM> of an assembly <NUM> according to the present disclosure. As shown, the electrical contact <NUM> may include a first component <NUM> and a second component <NUM> coupled together. The first and second components <NUM>, <NUM> may be coupled together after the first component <NUM> has been secured to a substrate <NUM>, which may include an electrically insulating material <NUM> sandwiched between first and second conductive layers <NUM>, <NUM>.

The first component <NUM> may include a first end <NUM> opposite a second end <NUM>. The first end <NUM> may include a flattened base <NUM> to provide support to the first component <NUM> and the second component <NUM>, and to increase adhesion of the first component <NUM> to the substrate <NUM>. The flattened base <NUM> may be soldered, sintered, or brazed to a top surface <NUM> of the first conductive layer <NUM>. As shown, the first component <NUM> may include a hollowed interior <NUM>, which extends to the top surface <NUM> of first conductive layer <NUM>. The first component <NUM> may be solid. The second end <NUM> may include a pointed or sloped tip <NUM> extending into an interior <NUM> of the second component <NUM>. The second end <NUM> may have a square, rectangular, circular, or oval cross section. The first end <NUM> may also, or alternatively, have a square, rectangular, circular, or oval cross section. It will be appreciated that the cross section of the first and second ends <NUM>, <NUM> may be the same or different.

The second component <NUM>, which may be a power terminal, includes a first end <NUM> opposite a second end <NUM>. It will be appreciated that the second end <NUM> is cutoff in the figure. The interior <NUM>, which is defined by an internal sidewall <NUM>, may extend between the first and second ends <NUM>, <NUM>. The first end <NUM> may extend generally to a top surface <NUM> of the flattened base <NUM>. As shown, the internal sidewall <NUM> may be in direct physical and electrical contact with an exterior surface <NUM> of the first component <NUM>. The first and second components <NUM>, <NUM> are preferably fitted together, which causes the first end <NUM> of the second component <NUM> to plastically deform laterally, e.g., in a direction parallel to a plane defined by the top surface <NUM> of the first conductive layer <NUM>. Although non-limiting, the first and second components <NUM>, <NUM> may be same material (e.g., copper) with a same hardness, thus allowing optimal cold welding and preventing CTE mismatch during extreme temperature. The first and second components <NUM>, <NUM> can also be different materials.

<FIG> demonstrates a partially exploded view of an electrical contact <NUM> of an assembly <NUM> according to present disclosure. As shown, the electrical contact <NUM> may include a first component <NUM> and a second component <NUM> coupled together. The first and second components <NUM>, <NUM> may be coupled together after the first component <NUM> has been secured to a substrate <NUM>, which may include an electrically insulating material <NUM> sandwiched between first and second conductive layers <NUM>, <NUM>.

The first component <NUM> may include a first end <NUM> opposite a second end <NUM>. The first end <NUM> may include a base <NUM> to provide support to the first component <NUM> and the second component <NUM>, and to increase adhesion of the first component <NUM> to the substrate <NUM>. The base <NUM> may be soldered, sintered, or brazed to a top surface <NUM> of the first conductive layer <NUM>. As shown, the first component <NUM> may include an exterior channel <NUM>, which extends between the base <NUM> and the second end <NUM>. The exterior channel <NUM> preferably functions as a stress relief feature for the assembly <NUM>. As further shown, the second end <NUM> may include a pointed or sloped tip <NUM> extending into an interior (not shown) of the second component <NUM>. The second end <NUM> may have a square, rectangular, circular, or oval cross section. The first end <NUM> may also, or alternatively, have a square, rectangular, circular, or oval cross section. It will be appreciated that the cross section of the first and second ends <NUM>, <NUM> may be the same or different.

The second component <NUM>, which may be a power terminal, includes a first end <NUM> opposite a second end <NUM>. Once coupled together, an internal sidewall of the second component <NUM> may be in direct physical and electrical contact with an exterior surface <NUM> of the first component <NUM>. The first and second components <NUM>, <NUM> are preferably fitted together, which causes the first end <NUM> of the second component <NUM> to plastically deform laterally, e.g., in a direction parallel to a plane defined by the top surface <NUM> of the first conductive layer <NUM>. Although non-limiting, the first and second components <NUM>, <NUM> may be same material (e.g., copper) with a same hardness, thus allowing optimal cold welding and preventing CTE mismatch during extreme temperature. The first and second components <NUM>, <NUM> can also be different materials.

Turning now to <FIG>, a method <NUM> according to the present disclosure will be described in greater detail. At block <NUM>, the method <NUM> may include coupling a first component of an electrical contact to a supporting structure, the first component including a pin defined by a sloped tip. At block <NUM>, the method <NUM> may further include coupling a second component to the first component, wherein the second component includes a hollow cylinder or a hollow cube.

As used herein, an element or step recited in the singular and proceeded with the word "a" or "an" is understood as not excluding plural elements or steps, unless such exclusion is explicitly recited.

Accordingly, the terms "including," "comprising," or "having" and variations thereof are open-ended expressions and can be used interchangeably herein.

The phrases "at least one", "one or more", and "and/or", as used herein, are open-ended expressions and are both conjunctive and disjunctive in operation. For example, expressions "at least one of A, B and C", "at least one of A, B, or C", "one or more of A, B, and C", "one or more of A, B, or C" and "A, B, and/or C" means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B and C together.

All directional references (e.g., proximal, distal, upper, lower, upward, downward, left, right, lateral, longitudinal, front, back, top, bottom, above, below, vertical, horizontal, radial, axial, clockwise, and counterclockwise) are just used for identification purposes to aid the reader's understanding of the present disclosure. The directional references do not create limitations, particularly as to the position, orientation, or use of the disclosure. Connection references (e.g., attached, coupled, connected, and joined) are to be construed broadly and may include intermediate members between a collection of elements and relative movement between elements unless otherwise indicated. As such, connection references do not necessarily infer two elements are directly connected and in fixed relation to each other.

Furthermore, identification references (e.g., primary, secondary, first, second, third, fourth, etc.) are not intended to connote importance or priority, and are used to distinguish one feature from another. The drawings are for purposes of illustration, and the dimensions, positions, order and relative sizes reflected in the drawings attached hereto may vary.

Claim 1:
An assembly(<NUM>), comprising:
a substrate (<NUM>); and
a press-fit pin (<NUM>) coupled to the substrate, wherein the press-fit pin (<NUM>) is operable to provide an electrical connection, and wherein the press-fit pin (<NUM>) comprises:
a base portion (<NUM>) including a base slot (<NUM>) defined by a first set of prongs (<NUM>) the base portion further comprising a first section (<NUM>) and one or more planar surfaces (<NUM>) extending from the first section (<NUM>), wherein the first section is circular;
an upper portion (<NUM>) stacked vertically atop the base portion (<NUM>) in an end-to-end arrangement, the upper portion (<NUM>) including an upper slot (<NUM>) defined by a second set of prongs (<NUM>), wherein the first set of prongs (<NUM>) engage the second set of prongs (<NUM>) when the the base portion (<NUM>) and the upper portion (<NUM>) are coupled together, wherein the planar surfaces of the base portion abut an inner surface (<NUM>) of the second set of prongs when the base portion and the upper portion are brought together, wherein the first section includes one or more prong slots (<NUM>) operable to receive the second set of prongs, wherein each prong slot comprises a radial surface (<NUM>) operable to abut a side surface (<NUM>) of the second set of prongs, wherein the planar surface in contact with the inner surface of the second set of prongs prevents movement of the upper portion along a first direction, wherein the radial surface in contact with the side surface of the second set of prongs prevents movement of the upper portion along a second direction, and wherein the first direction is perpendicular to the second direction