Pin seat and power module

Abstract

The invention discloses a contact pin seat and a power module, the contact pin seat comprises a contact pin main body part and a contact pin base, the contact pin main body part is provided with a first channel extending along the axial direction, and the first channel forms a first opening for a contact pin to insert at a first end of the contact pin main body part; the contact pin base part is connected to the second end of the contact pin main body part, the contact pin base part is provided with a second channel extending in the axial direction of the contact pin main body part, and the second channel forms a second opening in the end, away from the contact pin main body part, of the contact pin base part; the inner wall surface of the second channel comprises a first arc surface, the first arc surface is arranged to enable the radial cross section of the second channel to be gradually increased in the direction from the pin main body part to the pin base part so as to be suitable for flowing of solder paste, and the pin base part can be pressed to deform so as to enable at least part of the first arc surface to deform into a first plane, therefore, ultrasonic welding is facilitated. The contact pin seat can be applied to reflow soldering and ultrasonic soldering respectively, and an enterprise only needs to be equipped with one type of contact pin seat, so that the material management cost can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor devices, and in particular to a pin socket and a power module. Background Art

[0002] The power module has pins for connecting to external electrical appliances. The pins are plugged into the pin holder, which is connected to the substrate. Currently, the connection between the pin holder and the substrate mainly includes reflow soldering or ultrasonic soldering. Due to different processes, the pin holder used for ultrasonic soldering and the pin holder used for reflow soldering have different structures, which makes them non-interchangeable. Therefore, enterprises need to prepare two sets of pin holders, which increases material management costs. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a pin socket that can be used for reflow soldering and ultrasonic soldering, respectively, which helps to reduce material management costs.

[0004] The present invention also provides a power module using the pin socket.

[0005] The pin socket according to the first embodiment of the present invention comprises:

[0006] A pin body, the pin body having a first passage extending in the axial direction, the first passage forming a first opening at a first end of the pin body for inserting the pin;

[0007] A pin base connected to the second end of the pin body, the pin base having a second channel extending along the axial direction of the pin body, the second channel forming a second opening at one end of the pin base away from the pin body;

[0008] The inner wall surface of the second channel includes a first arc surface, and the first arc surface is configured to gradually increase the radial cross-section of the second channel along the direction from the pin body to the pin base to accommodate the flow of solder paste, and the pin base can be deformed under pressure to deform at least a portion of the first arc surface into a first plane to accommodate ultrasonic welding.

[0009] The pin socket according to the first embodiment of the present invention has at least the following beneficial effects:

[0010] The pin socket of this embodiment can be used for reflow soldering and ultrasonic soldering respectively, and the enterprise only needs to equip one pin socket, thereby reducing the material management cost. At the same time, this embodiment has a simple structure and is easy to promote and implement.

[0011] In other embodiments of the present invention, the pin socket satisfies the following configuration:

[0012] L = 2γ·cosθ / ρ·g·H;

[0013] Among them, in the reference plane passing through the axis of the pin body, the two endpoints of the projection of the first arc surface in the reference plane are respectively the first endpoint and the second endpoint, the first endpoint is closer to the pin body relative to the second endpoint, L is the radial distance between the first endpoint and the second endpoint, γ is the surface tension of the solder paste, θ is the angle between the tangent passing through the second endpoint and tangent to the first arc surface, ρ is the density of the solder paste, g is the acceleration of gravity, and H is the axial height of the solder paste attached to the first arc surface.

[0014] In other embodiments of the present invention, the end of the pin base away from the pin body includes a second plane, and the second plane is arranged around the first arc surface and connected to the first arc surface.

[0015] In other embodiments of the present invention, the pin socket satisfies the following configuration:

[0016] W1=(W2·Er·P) / (P+E);

[0017] Among them, in the reference plane passing through the axis of the pin body, the two endpoints of the projection of the first arc surface in the reference plane are respectively the first endpoint and the second endpoint, the first endpoint is closer to the pin body relative to the second endpoint, W1 is the radial width of the second plane of the pin base before compression deformation, W2 is the sum of the radial widths of the first plane and the second plane of the pin base after compression deformation, P is the pressure, E is the elastic modulus, and r is the radial distance between the second endpoint and the center axis of the pin base.

[0018] In other embodiments of the present invention, the pin socket satisfies the following configuration:

[0019]

[0020] Among them, W is the weight of the pin seat, r1 is the outer diameter of the end face of the first end of the pin body, r2 is the inner diameter of the end face of the first end of the pin body, P1 is the atmospheric pressure, and P2 is the negative pressure value of the negative pressure applied to the end face of the first end.

[0021] In other embodiments of the present invention, the pin body is configured as a cylindrical structure.

[0022] In other embodiments of the present invention, the outer wall surface of the pin base includes a second arc surface, and the second arc surface is concentric with the first arc surface.

[0023] In other embodiments of the present invention, the pin seat is formed by stamping.

[0024] A power module according to a second embodiment of the present invention includes:

[0025] substrate;

[0026] A chip connected to the substrate;

[0027] The pin socket described in the above embodiment, the pin base of the pin socket is connected to the substrate through solder paste, and the solder paste is attached to the first arc surface;

[0028] The plug pin is plugged into the first channel of the plug pin body.

[0029] A power module according to a third embodiment of the present invention includes:

[0030] substrate;

[0031] A chip connected to the substrate;

[0032] The pin socket described in the above embodiment, the pin base of the pin socket is connected to the substrate by ultrasonic welding, and the first plane of the pin base is in contact with the substrate;

[0033] The plug pin is plugged into the first channel of the plug pin body.

[0034] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0036] Figure 1 is a three-dimensional schematic diagram of a pin socket in an embodiment of the present invention;

[0037] Figure 2 for Figure 1 A cross-sectional view of the middle pin seat;

[0038] Figure 3 for Figure 1 The front view of the pin holder in the figure when used for reflow soldering;

[0039] Figure 4 for Figure 1 A front view of the pin socket when used for ultrasonic welding;

[0040] Figure 5 FIG. 4 is a side view of a power module in an embodiment of the present invention.

[0041] Reference numerals:

[0042] Pin seat 100, pin body 110, first channel 111, first opening 112, pin base 120, second channel 121, second opening 122, first arc surface 123, first endpoint 123a, second endpoint 123b, first plane 124, second plane 125, second arc surface 126, arc portion 127, straight portion 128;

[0043] Pin 200;

[0044] substrate 300;

[0045] Chip 400. DETAILED DESCRIPTION

[0046] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0047] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0048] In the description of the present invention, "several" means more than one, "many" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0049] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific content of the technical solution.

[0050] In the description of the present invention, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0051] As mentioned above, in order to adapt to the two different connection methods of reflow soldering and ultrasonic soldering, enterprises need to prepare two types of pin sockets. Among them, for the pin socket dedicated to ultrasonic soldering (for the convenience of description, it is named the first type of pin socket), it is necessary to fix the bottom end face of the pin socket directly on the substrate through the high-frequency vibration of the ultrasonic welding head, so the bottom end face of the pin socket is required to be tightly fitted with the substrate, so the bottom end face of this pin socket is usually a plane. For the pin socket dedicated to reflow soldering (for the convenience of description, it is named the second type of pin socket), in order to ensure that the solder paste can flow between the bottom end face of the pin socket and the substrate after being heated, its lower end face is usually provided with multiple recessed structures or hollow structures. Based on the above structure, if the first type of pin socket is connected to the substrate by reflow soldering, since its lower end face lacks a channel allowing the solder paste to flow freely, the solder paste is prone to local accumulation, tin overflow, cold solder joints and other problems. In this case, the pin socket will be skewed due to the surface tension of the molten solder paste and the pin socket's own gravity, which will cause the top of the pin plugged into the pin socket to be skewed to a large extent; if the second type of pin socket is connected to the substrate by ultrasonic welding, since the lower end face has a recessed structure or a hollow structure, the fitting area between the lower end face and the substrate is reduced, which will affect the final welding quality. In summary, these two types of pin sockets cannot be used interchangeably.

[0052] Based on the above, the present invention proposes a pin socket that can be used for both ultrasonic welding and reflow soldering. Therefore, the enterprise only needs to equip one pin socket, thereby reducing material management costs. Figure 1 The pin socket 100 in the embodiment of the present invention mainly includes two parts: a pin body 110 and a pin base 120, wherein the pin body 110 is used for pin insertion, and the pin base 120 is used for connecting with the substrate.

[0053] Reference Figure 2 The pin body 110 has a first passage 111 extending in the axial direction. The first passage 111 forms a first opening 112 for inserting the pin at a first end of the pin body 110. For example, when the pin seat 100 is in Figure 2In the normal installation posture, the first channel 111 extends in the up-down direction and forms a first opening 112 at the upper end of the pin body 110. The sizes of the first channel 111 and the first opening 112 match the pin 200. In this way, the pin 200 can be inserted into the first channel 111 through the first opening 112 and kept fixed by interference fit with the first channel.

[0054] The pin base 120 is connected to the second end of the pin body 110. The pin base 120 has a second channel 121 extending along the axial direction of the pin body 110. The second channel 121 forms a second opening 122 at one end of the pin base 120 away from the pin body 110. Figure 2 As shown in the figure for illustration, the second channel 121 extends in the up-down direction and forms a second opening 122 at the lower end of the pin base 120 .

[0055] In this embodiment, refer to Figure 2 , Figure 3 , Figure 3 The schematic diagram of solder paste attached to the inner wall of the second channel 121 is shown in FIG. The inner wall of the second channel 121 includes a first arc surface 123. The first arc surface 123 is configured to gradually increase the radial cross section of the second channel 121 along the direction from the pin body 110 to the pin base 120 to accommodate the flow of solder paste. For example, the upper end of the first arc surface 123 is connected to the inner wall of the first channel 111, and the lower end extends to the lower end surface of the pin base 120. In addition, the radial cross section of the second channel 121 gradually increases from top to bottom. In this embodiment, the first arc surface 123 is provided to form a second channel 121 with a gradually increasing cross-sectional area. The melted solder paste can flow in the second channel 121 and be evenly distributed, thereby meeting the soldering requirements of reflow soldering. It should be noted that the aforementioned melted solder paste can flow and be evenly distributed based on the standard atmospheric pressure. Unless otherwise specified, the corresponding effects are described in the present invention based on the standard atmospheric pressure.

[0056] On the other hand, refer to Figure 2 , Figure 3 , Figure 4 Schematic diagram of the pin seat after ultrasonic welding. As shown in the figure, the pin base 120 can be deformed by pressure, so that at least part of the first arc surface 123 is deformed into a first plane 124 (for ease of understanding, Figure 4The first plane 124 is roughly marked by a dotted line in the figure), and the first plane 124 can be kept in contact with the substrate, so as to meet the welding requirements of ultrasonic welding. It should be noted that the ultrasonic welding is completed by an ultrasonic welding head. Exemplarily, the ultrasonic welding head includes a sleeve structure, which can be sleeved on the outside of the pin body 110 and abut against the outside of the pin base 120. As the sleeve structure is pressed down, the pin base 120 can shrink and abut against the substrate, so that at least part of the first arc surface 123 is deformed from an arc surface to a plane.

[0057] In summary, the pin socket 100 of this embodiment can be used for reflow soldering and ultrasonic soldering respectively, and the enterprise only needs to equip one pin socket, thereby reducing the material management cost. At the same time, the present invention has a simple structure and is easy to promote and implement.

[0058] On the basis of the first embodiment, in some embodiments of the present invention, when the pin socket 200 is applied to reflow soldering, it is necessary to ensure that there is a certain contact area between the solder paste and the first circular arc surface 123, that is, it is necessary to ensure that the solder paste has a certain adhesion height, so as to ensure the welding strength of the pin socket 100. Based on this, this embodiment further defines the relationship between the first circular arc surface 123 and the solder paste adhesion height as: L=2γ·cosθ / ρ·g·H.

[0059] The definitions of the parameters in the above formula are as follows: L is the width of the first arc surface 123 in the radial direction. Figure 2 First, define a reference plane passing through the axis of the pin body 110. The projection of the first arc surface 123 in the reference plane is two symmetrically arranged arc lines. Select one of the arc lines, and name the one of its two endpoints closer to the pin body 110 as the first endpoint 123a, and the other as the second endpoint 123b (for example, the first endpoint 123a is the upper endpoint, and the second endpoint 123b is the lower endpoint). Then L is the distance between the first endpoint 123a and the second endpoint 123b along the radial direction of the pin base 120. In addition, γ is the surface tension of the solder paste, and θ is the distance between the tangent line passing through the second endpoint 123b and tangent to the first arc surface 123 and the lower end surface of the pin base 120 (that is, Figure 2 The angle between the horizontal plane) is ρ, ρ is the density of solder paste, g is the acceleration of gravity, refer to Figure 3 , H is the axial height of the solder paste attached to the first arc surface 123. For example, when the solder paste parameters are: γ is 0.5 N / m, θ is 30°, ρ is 8400 kg / m 3 When the solder paste adhesion height H is 2.189mm, it can meet the contact area requirement. Combining the above formula, we can get L to be 0.5mm.

[0060] Based on the first embodiment, in some embodiments of the present invention, referring to Figure 2 The end of the pin base 120 away from the pin body 110 includes a second plane 125, which is arranged around the first arc surface 123 and connected to the first arc surface 123, wherein the second plane 125 can be welded to the substrate during ultrasonic welding, thereby increasing the welding area between the pin seat 100 and the substrate and ensuring the connection strength of the pin seat 100. Specifically, refer to Figure 1 The pin base 120 further includes an arc portion 127 and a straight portion 128 . The inner wall surface of the arc portion 127 is provided with the aforementioned first arc surface 123 . The straight portion 128 is provided around the arc portion 127 , and the lower end of the straight portion 128 is provided with the aforementioned second plane 125 .

[0061] As described above, when the pin base 120 is deformed during the ultrasonic welding process, the first plane 124 and the second plane 125 will both fit with the substrate. Therefore, the interconnected first plane 124 and the second plane 125 can be regarded as an integral annular plane (for the convenience of description, it is named the third plane). In order to ensure the connection strength of the pin socket 200, in some embodiments of the present invention, the width relationship between the second plane 125 and the third plane is also limited to: W1 = (W2·Er·P) / (P+E).

[0062] The definitions of the parameters in the above formula are as follows: Figure 2 , W1 is the width of the second plane 125 of the pin base 120 along the radial direction of the pin base 120 before the pin base 120 is compressed and deformed, refer to Figure 4 , W2 is the sum of the widths of the first plane 124 and the second plane 125 along the radial direction of the pin base 120 after the pin base 120 is deformed by pressure, that is, the width of the third plane, P is the pressure, E is the elastic modulus, r is the radial distance between the second endpoint 123b and the central axis of the pin base 120, wherein the second endpoint 123b can be understood with reference to the aforementioned embodiment.

[0063] In this embodiment, the width of the second plane 125 of the pin socket 100 when it is in an undeformed state can be determined by the width of the contact area between the pin socket 100 and the substrate when it is applied to ultrasonic welding.

[0064] On the basis of the first embodiment, in some embodiments of the present invention, the pin holder 100 is suitable for transfer by vacuum adsorption. Based on this, the pin holder 100 of this embodiment meets the following requirements:

[0065] The definitions of the parameters in the above formula are as follows: W is the weight of the pin holder, refer to Figure 3 , Figure 4, r1 is the outer diameter of the end face of the first end of the pin body 110, r2 is the inner diameter of the end face of the first end of the pin body 110, P1 is the atmospheric pressure, and P2 is the negative pressure value generated by the vacuum applied to the end face of the first end. It should be noted that the transfer of the pin holder 100 is achieved by a vacuum adsorption head. For example, the vacuum adsorption head abuts against the end face of the first end of the pin body 110, and the pin holder 100 is adsorbed by the negative pressure generated by the vacuum adsorption head. In this embodiment, the maximum weight of the pin holder 100 that can be transferred by vacuum adsorption can be determined by the negative pressure of the vacuum adsorption device and the inner and outer diameters of the end face of the first end of the pin body 110.

[0066] On the basis of the first embodiment, in some embodiments of the present invention, the pin body 110 is configured as a cylindrical structure, which is convenient for the insertion of the pin on the one hand, and also convenient for the socketing of the ultrasonic welding head on the other hand.

[0067] Based on the first embodiment, in some embodiments of the present invention, referring to Figure 1 The outer wall surface of the pin base 120 includes a second arc surface 126, and the second arc surface 126 is concentric with the first arc surface 123. In some specific implementations, the wall thickness of the pin base 120 is equal to or slightly smaller than the wall thickness of the pin body 110, so that the pin seat 100 is suitable for forming by stamping.

[0068] On the basis of the first embodiment, in some embodiments of the present invention, the pin seat 100 is formed by stamping, that is, the pin body 110 and the pin base 120 are connected as an integral structure, which is easy to produce and process.

[0069] The second embodiment of the present invention provides a power module, referring to Figure 5 , which includes a pin 200 , a substrate 300 , a chip 400 and the pin socket 100 in the aforementioned embodiments, wherein the chip 400 and the pin socket 100 are both connected to the substrate 300 , and the pin 200 is plugged into the first channel 111 of the pin socket 100 .

[0070] The substrate 300 may be a ceramic substrate, which includes a ceramic layer and metal layers disposed on opposite sides of the ceramic layer. Exemplarily, the chip 400 and the pin holder 100 are connected to the metal layer on the same side of the substrate 300. In addition, the power module further includes a molded body, not shown, in which the chip 400, the pin holder 100 and part of the substrate 300 are encapsulated, and the top of the pin 200 extends from the molded body to be connected to an external electrical device.

[0071] In this embodiment, the pin base 120 of the pin holder 100 is connected to the substrate 300 through solder paste, and the solder paste is attached to the first arc surface 123 .

[0072] The third embodiment of the present invention provides a power module, referring to Figure 5 , which includes a pin 200 , a substrate 300 , a chip 400 and the pin socket 100 in the aforementioned embodiments, wherein the chip 400 and the pin socket 100 are both connected to the substrate 300 , and the pin 200 is plugged into the first channel 111 of the pin socket 100 .

[0073] The substrate 300 may be a ceramic substrate, which includes a ceramic layer and metal layers disposed on opposite sides of the ceramic layer. Exemplarily, the chip 400 and the pin holder 100 are connected to the metal layer on the same side of the substrate 300. In addition, the power module further includes a molded body, not shown, in which the chip 400, the pin holder 100 and part of the substrate 300 are encapsulated, and the top of the pin 200 extends from the molded body to be connected to an external electrical device.

[0074] In this embodiment, the pin base 120 of the pin holder 100 is connected to the substrate 300 by ultrasonic welding. At this time, at least a portion of the first arc surface 123 is deformed into a first plane 124 , and the first plane 124 is kept in contact with the substrate 300 .

[0075] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. Pin socket, characterized in that: include: A pin body, the pin body having a first passage extending in the axial direction, the first passage forming a first opening at a first end of the pin body for inserting the pin; A pin base connected to the second end of the pin body, the pin base having a second channel extending along the axial direction of the pin body, the second channel forming a second opening at one end of the pin base away from the pin body; The inner wall surface of the second channel includes a first arc surface, and the first arc surface is configured to gradually increase the radial cross-section of the second channel along the direction from the pin body to the pin base to accommodate the flow of solder paste, and the pin base can be deformed under pressure to deform at least a portion of the first arc surface into a first plane to accommodate ultrasonic welding.

2. The pin socket according to claim 1, characterized in that: The pin socket meets the following requirements: L = 2γ·cosθ / ρ·g·H; Among them, in the reference plane passing through the axis of the pin body, the two endpoints of the projection of the first arc surface in the reference plane are respectively the first endpoint and the second endpoint, the first endpoint is closer to the pin body relative to the second endpoint, L is the radial distance between the first endpoint and the second endpoint, γ is the surface tension of the solder paste, θ is the angle between the tangent passing through the second endpoint and tangent to the first arc surface, ρ is the density of the solder paste, g is the acceleration of gravity, and H is the axial height of the solder paste attached to the first arc surface.

3. The pin socket according to claim 1, characterized in that: The end of the pin base away from the pin body includes a second plane, and the second plane is arranged around the first arc surface and connected to the first arc surface.

4. The pin socket according to claim 3, characterized in that: The pin socket meets the following requirements: W1=(W2·Er·P) / (P+E); Among them, in the reference plane passing through the axis of the pin body, the two endpoints of the projection of the first arc surface in the reference plane are respectively the first endpoint and the second endpoint, the first endpoint is closer to the pin body relative to the second endpoint, W1 is the radial width of the second plane of the pin base before compression deformation, W2 is the sum of the radial widths of the first plane and the second plane of the pin base after compression deformation, P is the pressure, E is the elastic modulus, and r is the radial distance between the second endpoint and the center axis of the pin base.

5. The pin socket according to claim 1, characterized in that: The pin socket meets the following requirements: Among them, W is the weight of the pin seat, r1 is the outer diameter of the end face of the first end of the pin body, r2 is the inner diameter of the end face of the first end of the pin body, P1 is the atmospheric pressure, and P2 is the negative pressure value of the negative pressure applied to the end face of the first end.

6. The pin socket according to claim 1, characterized in that: The pin body is configured as a cylindrical structure.

7. The pin socket according to claim 1, characterized in that: The outer wall surface of the pin base includes a second arc surface, and the second arc surface is concentric with the first arc surface.

8. The pin socket according to claim 1, characterized in that: The pin seat is formed by stamping.

9. A power module, characterized in that: include: substrate; A chip connected to the substrate; The pin socket according to any one of claims 1 to 8, wherein the pin base of the pin socket is connected to the substrate via solder paste, and the solder paste is attached to the first arc surface; The plug pin is plugged into the first channel of the plug pin body.

10. A power module, characterized in that: include: substrate; A chip connected to the substrate; The pin socket according to any one of claims 1 to 8, wherein the pin base of the pin socket is connected to the substrate by ultrasonic welding, and the first plane of the pin base is in contact with the substrate; The plug pin is plugged into the first channel of the plug pin body.

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