Method for attaching terminal to metal substrate structure for semiconductor power module, and semiconductor power module

Abstract

A method for attaching a terminal (4) to a metal substrate structure (3) for a semiconductor power module (10) comprises providing at least one terminal (4), providing a metal substrate structure (3) having a metal top layer (17), a metal bottom layer (19) and an isolation resin layer (18) disposed between the metal top layer (17) and the metal bottom layer (19). The method further comprises providing at least one blind hole (7) passing through the metal bottom layer (19) and the isolation layer (18) such that the at least one terminal (4) is positioned on the metal top layer (17) opposite the blind hole (7) and the at least one terminal (4) is coupled to the metal top layer (17) by welding.

Description

Technical Field

[0001] The present disclosure relates to a method for attaching a terminal to a metal substrate structure for a semiconductor power module having an isolation layer. The present disclosure also relates to a semiconductor power module for a semiconductor device. Background Art

[0002] EP0645815A2 describes a high-power module including a high-power, high-frequency semiconductor switch device and an operating method thereof. The high-power module has composition, geometry and electrical symmetry. The high-power module also includes short internal leads, a special IC chip substrate, an adjustable gate lead resistor, a special composite metal / ceramic substrate and a special terminal conductor overlap structure.

[0003] Conventional insulated metal substrates have realized low-power and medium-power semiconductor module technologies with both low insulation requirements and low thermal resistance requirements. The terminals are attached to the insulated metal substrate, and there is a need to reliably connect the terminals to the insulated metal substrate. For low reliability requirements, the terminals can be brazed or glued to the substrate. The welding process may be critical to the substrate structure. In view of the traditional setting of such an insulated metal substrate, the corresponding terminals are connected to the top metallization using a welding technique to provide a bonding connection. This may be critical for a stable process on a substrate with a resin insulating sheet under the metallization. The welding process may cause damage to the substrate structure, for example, due to the friction and pressure between the terminal pins and the substrate, ultrasonic welding brings a strong impact of thermal stress, mechanical stress and thermomechanical stress on the substrate structure. Here, the resin sheet is strongly harmed by deformation and crack formation. In addition, there is a risk of delamination of the metallization from the resin sheet layer. When ultrasonic welding of terminal pins is applied to the circuit metallization of the insulated metal substrate, corresponding failure modes may occur. Summary of the invention

[0004] One objective is to avoid failure modes due to soldering of terminal feet on the metallization.

[0005] This object is solved by the features of the independent claims.

[0006] Therefore, a method of attaching a terminal to a metal substrate structure is provided, which helps to realize a cost-effective metal substrate structure for a semiconductor power module, which can ensure reliable operation even in high voltage power module applications with high reliability requirements. In addition, a corresponding semiconductor power module is provided.

[0007] Therefore, a method for attaching a terminal to a metal substrate structure for a semiconductor power module includes: providing at least one terminal having a terminal body and a terminal foot, and providing a metal substrate structure having a metal top layer, a metal bottom layer, and an isolation layer disposed between the metal top layer and the metal bottom layer. The method also includes providing at least one blind hole through the metal bottom layer and the isolation layer, so that at least one unsupported portion of the metal top layer is available. The method also includes connecting at least one terminal to at least one unsupported portion of the metal top layer of the metal substrate structure by welding, thereby avoiding a failure mode caused by welding the terminal foot on the metallization portion.

[0008] The terminals can be implemented as main terminals and / or auxiliary terminals made of copper or copper alloy, and are welded to the circuit metallization of the insulating metal substrate by, for example, ultrasonic welding and / or laser welding or other applicable welding methods. Depending on the type and material of the terminal, the terminal pins can have a thickness of 0.25 mm to 2.0 mm. In order to improve the welding process or protection (for example, to prevent oxidation), the top surface of the substrate and / or the terminal pins can be coated with a metal layer, which is made of, for example, nickel, silver and / or gold.

[0009] As the welding means, it is advantageous to use ultrasonic welding using an ultrasonic welding head or laser welding using a laser beam. The above welding head is also called a sonotrode.

[0010] Blind vias are intentionally formed cavities in the metal bottom layer and the isolation resin layer. Blind vias protect the isolation layer from mechanical and thermal shock caused by ultrasonic welding and / or laser welding, and realize an unsupported section of the circuit metallization of the metal top layer under the terminal. Blind vias provide a space, thereby reducing the propagation of mechanical and thermal stresses to the isolation layer.

[0011] The locations where the terminals are mounted on the insulated metal substrate are usually not as demanding on heat dissipation. There are no blind vias at locations where thermal issues are important (such as directly under the chip where strong heat dissipation occurs).

[0012] During the welding process, a counter element can be applied to the open back side of the unsupported portion of the circuit metallization to provide mechanical support. During the welding process, the metal substrate is exposed to strong mechanical shocks (such as pressure and vibration, which usually occurs in ultrasonic welding), and the use of counter elements may be particularly necessary. The counter element can also provide improved heat dissipation, reducing the lateral heat flow in the circuit metallization and the surrounding substrate structure. In addition, it can be considered to at least temporarily protect the chip or other module structure from the influence of particles generated during the welding process. The corresponding protection can be achieved by coating the sensitive structure (for example, by a resin material).

[0013] After the soldering process is finished, the blind holes can be filled with epoxy or other electrically insulating materials. The material used for filling can contain any filler material (such as particles or fibers) to improve mechanical and thermal properties. The filling process can be done by dispensing or injection, for example.

[0014] Due to the described method, it is possible to realize ultrasonic welding and / or laser welding connection on the insulating metal substrate, which contributes to the stable and reliable operation of the semiconductor power module, even for high voltage power module applications. The method helps to firmly attach the terminal to the insulating metal substrate by, for example, ultrasonic welding and / or laser welding and / or other applicable welding methods, while reducing the risk of damage to the isolation layer.

[0015] For alternative joining processes, ultrasonic welding and / or laser welding provide higher reliability of ultrasonic welding interface and / or laser welding interface to thermal load cycles compared with soldering or gluing, and improve the heat conduction of the interface, simplify the manufacturing process and improve the yield. Ultrasonic welding and / or laser welding, as a mature technology, can also be used for insulated metal substrate structures due to blind holes through the metal substrate and the isolation layer. No need to redesign the housing or terminals.

[0016] By using the method for manufacturing a metal substrate structure with one or more attached terminals, the aforementioned adverse effects can be offset due to the blind holes specially introduced through the metal bottom layer and the isolation layer. The one or more blind holes in the metal substrate structure inhibit or reduce severe damage to the underlying isolation layer near the welded connection caused by mechanical and thermal shock when welding the terminals on the insulated metal substrate structure. The risk of crack formation or damage in the isolation layer and the risk of delamination of the metal top layer can be reduced. In general, the blind hole provides a space, thereby reducing the propagation of thermal stress, mechanical stress and thermomechanical stress on the substrate structure, especially into the isolation layer.

[0017] Stable semiconductor power modules are feasible, and reliable operation can be achieved even in high voltage power module applications (e.g., in the voltage range of 0.5 kV to 10.0 kV). However, the method also allows the manufacture of metal substrate structures and semiconductor power modules, which can be applied to various products, such as low voltage industrial products and automotive products operating in the voltage range of 0.5 kV or lower. For example, one or more terminals can be directly soldered to the surface of the metal top layer to form a direct copper-to-copper contact.

[0018] Finally, it should be pointed out that the proposed features and methods can be used individually or in combination of two or more.

[0019] The present disclosure relates to welding, such as ultrasonic welding and / or laser welding of power terminals and auxiliary terminals on an insulated metal substrate or an insulated metal base plate, and also to ultrasonic welding and / or laser welding of power terminals and auxiliary terminals on a substrate structure (such as a stamped and molded metal substrate structure) based on an alternative metal substrate structure technology. For example, the insulated metal substrate includes a relatively thick metal base layer or bottom layer made of aluminum and / or copper and / or corresponding alloys. The insulated metal substrate also includes a resin material-based isolation sheet forming a resin layer, and a circuit metallization portion made of aluminum and / or copper and / or corresponding alloys forming a metal top layer. The resin material used for the isolation sheet is typically a thermosetting resin containing a thermally conductive filling material or a thermoplastic resin.

[0020] Since the metal substrate structure can be manufactured by embodiments of the method, and since the semiconductor power module includes embodiments of the metal substrate structure, features and characteristics of the method are also disclosed for the metal substrate structure and the semiconductor power module, and vice versa. Thus, the present disclosure includes multiple aspects, wherein each feature described for one aspect is also disclosed herein for other aspects, even if the corresponding feature is not explicitly mentioned in the context of a particular aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Exemplary embodiments are explained below with the aid of schematic diagrams and reference numerals. The accompanying drawings show:

[0022] Figure 1 One embodiment of a terminal attached to a metal substrate structure of a semiconductor power module is shown in side view;

[0023] Figure 2-3 Several embodiments of terminals for attachment to a metal substrate structure are shown in respective side views;

[0024] Figure 4 One embodiment of a terminal foot attached to a metal substrate structure relative to a blind hole is shown in a corresponding top view;

[0025] Figure 5 A flow chart of a method for attaching one embodiment of a terminal to a metal substrate structure is shown.

[0026] The accompanying drawings are included to provide further understanding. It should be understood that the embodiments shown in the figures are illustrative representations and are not necessarily drawn to scale. The same reference numerals represent elements or components having the same function. As long as the elements or components in different figures correspond to each other in function, their description will not be repeated for each of the following figures. For clarity, elements may not be shown with corresponding reference numerals in all figures. DETAILED DESCRIPTION

[0027] Figure 1A side view of a terminal 4 attached to a metal substrate structure 3 of a semiconductor power module 10 for a semiconductor device is shown. The semiconductor power module 10 includes a metal substrate structure 3 having a metal top layer 17, a metal bottom layer 19, and an isolation layer 18. The isolation layer 18 is disposed between the metal top layer 17 and the metal bottom layer 19 relative to a stacking direction A.

[0028] In this regard, terms such as "above", "below", "top", "upper" and "bottom" refer to positions or directions shown in the figures and relative to the stacking direction A. Thus, the height or thickness of the described elements is related to the stacking direction A, while the lateral direction B is oriented perpendicular to the stacking direction A (see FIG. Figure 1 , Figure 2 and Figure 3 ).

[0029] The metal substrate structure 3 further comprises at least one blind hole 7, the circumscribed circle diameter of the blind hole 7 being d_bh, which passes through the metal bottom layer 19 and the isolation layer 18. Thus, at least one unsupported portion 171 of the metal top layer 17 is available. The terminal 4 is intended to be connected to the unsupported portion 171 of the metal top layer 17 by a welding connection 45, wherein the circumscribed circle diameter of the welding connection 45 is d_wc, for example, by ultrasonic welding using an ultrasonic welding head 6 (not shown in the figure) and / or by laser welding using a laser beam 60 (not shown in the figure). Thus, the unsupported portion 171 of the metal top layer 17 is materially bonded to the terminal 4. The circumscribed circle diameter d_wc of the welding connection 45 is less than or equal to the circumscribed circle diameter d_bh of the blind hole 7. After welding is completed, at least one blind hole 7 is at least partially filled with a filling material 12 comprising a dielectric material (such as epoxy resin, thermoplastic resin or any other electrically insulating material). The filling material 12 may contain fillers (such as particles or fibers) to improve or adjust thermal properties and / or mechanical properties.

[0030] The terminal 4 comprises an L-shaped structure having a terminal body 41 extending mainly in the stacking direction A and a terminal foot 42 extending mainly in the transverse direction B. The transverse direction B is substantially perpendicular to the stacking direction A. Alternatively, the terminal comprises a U-shaped structure having two terminal bodies 41 extending mainly in the stacking direction A and a terminal foot 42 extending mainly in the transverse direction B. The terminal 4 comprises copper, aluminum and / or a corresponding alloy and can be implemented as a main terminal or an auxiliary terminal of the semiconductor power module 10. The terminal foot 42 is formed as a plate having a thickness of 0.5 mm to 2.0 mm in the stacking direction A. The terminal foot 42 can be partially or entirely thinned to a thickness of 0.5 mm or less. Therefore, the thickness of the terminal foot 42 is between 0.25-2.0 mm. The terminal foot 42 is formed as a plate having a thickness of 0.5 mm to 2.0 mm in the stacking direction A. The terminal foot 42 can be partially or entirely thinned to include a thickness of 0.5 mm or less. Therefore, the terminal foot 42 has a thickness between 0.25-2.0 mm.

[0031] The terminal foot 42 includes a structure for improving ultrasonic welding and / or laser welding. Such welding structure can be achieved by roughening or thinning areas, one or more grooves, grooves, depressions and / or holes on the terminal foot 42 of the terminal 4 (see Figure 2 ). Such a welding structure can be prepared on the top side 43 and / or the bottom side 44 of the corresponding terminal 4. The specific terminal structure can beneficially affect the ultrasonic welding process and / or the laser welding process and can help to form a material-bonded welded joint. In particular, by reducing the welding power, the thermal shock and mechanical shock of the welding process are further reduced.

[0032] Alternatively or additionally, the entire terminal foot 42 is formed thinner than the body 41 of the terminal 4. For example, the thickness of the thinned terminal foot 42 may range from 0.3 to 0.8 times the thickness of the terminal body 41.

[0033] The welding process is carried out on this thinner section. Thus, a stress-reduced ultrasonic welding process is provided. Furthermore, the laser energy required to achieve the laser welding connection is reduced, since the amount of metal that needs to be melted is lower and the lateral heat dissipation is reduced.

[0034] Furthermore, the terminal 4 may include a first coating 5 that partially or completely covers the top surface 43 of the terminal foot 42 (see Figure 3 ). The coating 5 is, for example, an anti-reflection coating, which is configured to face the incident laser beam 60 (not shown in the figure) during laser welding and, for example, improves the irradiation efficiency of the laser beam 60. The terminal 4 may also include a second coating 9 (not shown in the figure) that partially or completely covers the bottom surface 44 of the terminal 4.

[0035] The first coating 5 and the second coating 9 can beneficially affect the ultrasonic welding process and / or the laser welding process. The first coating 5 and the second coating 9 can, for example, protect the surface of the terminal 4 from oxidation and can be made of or include a precious metal, such as nickel, gold, silver and / or other metals. The second coating 9 below can also be used to attach the terminal 4 to the metal top layer 17 that supports any type of welding process.

[0036] This specification of the material of the connecting partner contributes to a safe and reliable welding process.

[0037] The thickness of the isolation layer 18 is between 100-200 μm. The thickness of the circuit metallization formed by the metal top layer 17 is between 150-500 μm. The thickness of the metal bottom layer 19, which can be implemented as a substrate, can be between 2-5 mm, which can also be configured to dissipate heat from the metal substrate structure 3 and the semiconductor power module 10. The isolation layer 18 may include an epoxy resin material, but may also include other types of resins such as other thermosetting resins or thermoplastic resins. The resin material may include fillers such as inorganic particles or fibers to improve heat dissipation and isolation performance. The isolation layer 18 forms a dielectric layer and can be implemented as a resin sheet or a prepreg sheet, which is assembled between the two top and bottom metal plates forming the metal top layer 17 and the metal bottom layer 19. For example, such a metallized sheet or plate is combined with the insulating layer of the dielectric resin layer 18 by a lamination process. The metallization structure required for the metal top layer 17 can then be completed by subsequent masking and etching process steps to locally remove the conductive metal to form the final metallization structure 17. Alternatively, the top metallization structure 17 may be formed by cutting or punching, for example before forming the finished metal substrate structure 3 .

[0038] Alternatively, the isolation layer 18 can be formed by molding, such as by injection molding, transfer molding or compression molding. For such molded isolation layer 18, the molding substance is implemented as a pumpable substance with predetermined material properties. The pumpable substance is a liquid or viscous raw material of the resin layer to be formed. For example, the molding substance is a liquid based on epoxy resin and / or ceramic. Alternatively or additionally, the raw material of the isolation layer 18 can be a thermosetting or thermoplastic resin material, such as polyamide, PBT, PET. Alternatively or additionally, the raw material of the isolation layer 18 includes an inorganic filler for adjustment of the improved thermal conductivity and / or thermal expansion coefficient (CTE) relative to the metal top layer 17 and / or the metal bottom layer 19. The molded isolation layer 18 includes a resin-based dielectric material with a ceramic filler material (e.g., Al2O3, AlN, BN, Si3N4 or SiO2). For example, the isolation layer 18 is an epoxy resin with fillers. The isolation layer 18 may also be based on other materials suitable for transfer molding, injection molding or compression molding or other suitable molding techniques, such as bismaleimide, cyanate ester, polyimide and / or silicone. Alternatively or additionally, the isolation layer 18 may include a ceramic material and / or a wet-set material or a material combination of two or more of the above components. The isolation layer 18 has a thickness of 100 μm to 200 μm.

[0039] The metal bottom layer 19 comprises copper and / or aluminum and / or corresponding alloys. The circuit metallization formed by the metal top layer 17 comprises copper and / or aluminum and / or corresponding alloys. In addition, the metal top layer 17 can be partially or completely coated. The corresponding coating of the circuit metallization comprises precious metals (e.g. nickel and / or gold and / or silver) and / or other metals.

[0040] Figure 4 The size and positioning of the solder connection 45 of the terminal foot above the blind hole 7 are shown in the top view. Figure 4 The terminal pin 42 (not shown) can be positioned at the center or peripheral eccentric position above the blind hole 7. Figure 4 The circumscribed circle diameter (not shown) may be greater than, less than or equal to the circumscribed circle diameter d_bh of the blind hole 7. Figure 4 The shape of the terminal pin 42 (not shown) and the blind hole 7 can be any geometric shape, such as a square, rectangle, circle or other polygonal geometric shape. The circumscribed circle diameter d_wc of the solder connection portion 45 of the terminal pin is less than or equal to the circumscribed circle diameter d_bh of the blind hole 7. Therefore, the area of ​​the solder connection portion 45 of the terminal pin is less than or equal to the cross-sectional area of ​​the blind hole 7. Even if the terminal pin 42 ( Figure 4 ) is slightly off-center relative to the blind hole 7, and no part of the welded connection 45 is located on the isolation layer 18 ( Figure 4 Above a portion of the device (not shown).

[0041] The steps of the method of attaching the terminal 4 to the metal substrate structure 3 may be as follows: Figure 5 According to the flowchart shown. Figure 1 In the illustrated embodiment, at least one terminal 4 is provided in step S1. The terminal 4 may include a first coating 5 and / or a second coating 9 on the top surface 43 and / or the bottom surface 44 of its terminal foot. The first coating 5 is an anti-reflection coating, for example for improving the laser welding process.

[0042] In step S2, a metal substrate structure 3 is provided, which includes a metal top layer 17, a metal bottom layer 19 and an isolation layer 18 arranged therebetween. The metal substrate structure 3 may also have a coating at least partially on its surface, in particular on the metal top layer 17.

[0043] In step S3, a blind via 7 is provided through the metal bottom layer 19 and the isolation layer 18. Alternatively, the blind via 7 may have been provided during the manufacture of the metal bottom layer 19 and the isolation layer 18 before step S1.

[0044] In an optional step S4 , a counter element 8 is introduced into the blind hole 7 through the metal base layer 19 and the isolation layer 18 to provide mechanical support and / or improved heat dissipation during the soldering process.

[0045] In a further step S5, the terminal 4 is welded to the unsupported portion 171 of the metal top layer 17. Thus, the terminal 4 is coupled to the metal top layer 17 of the metal substrate structure 3 by ultrasonic welding by the ultrasonic welding head 6 and / or by laser welding by the laser beam 60 or any other applicable welding method. Due to the welding process, a weld joint is formed between the terminal 4 and the metal top layer 17. Therefore, the terminal 4 and the metal top layer 17 are firmly bonded and materially bonded. In the case of laser welding, the anti-reflection coating 5 partially or completely covers the top surface 43 of the terminal 4 facing the incident laser beam 60 and improves the laser welding process.

[0046] In a further optional step S6 , if the counter element 8 was introduced in step S4 , the counter element 8 is removed from the blind hole 7 .

[0047] In another optional step S7 , the blind hole 7 is filled with a filling material 12 comprising a dielectric material (such as epoxy resin, thermoplastic resin or any other electrically insulating material).

[0048] Compared to conventional substrates based on ceramic spacers, the insulated metal substrate 3 is composed of a relatively thick metal base layer 19 (including aluminum and / or copper and / or corresponding alloys), an isolation layer 18 based on a resin material, and a circuit metallization 17 including aluminum and / or copper and / or corresponding alloys. The resin material used for the isolation layer 18 is usually an epoxy resin or other thermosetting resin containing a thermally conductive inorganic filler. An advantageous component of such a filler may be ceramic particles made of aluminum nitride (AlN), silicon nitride (Si3N4), boron nitride (BN) and / or aluminum oxide (Al2O3).

[0049] By implementing the blind hole 7 through the metal bottom layer 19 and the isolation layer 18 of the metal substrate structure 3, the mechanical, thermal and / or thermomechanical effects of the ultrasonic welding process and / or laser welding process on the isolation layer 18 are reduced or suppressed. A welded connection 45 is then formed between the terminal foot 42 of the terminal 4 and the unsupported portion of the metal top layer 19, thereby reducing the propagation of mechanical and thermal stresses into the metal substrate structure 3 and thus into the isolation layer 18, thereby reducing mechanical and thermal stresses. The blind hole 7 through the metal bottom layer 19 and the isolation layer 18 is provided before ultrasonic welding and / or laser welding of the main terminal or auxiliary terminal 4.

[0050] The ultrasonic welding process is carried out in cooperation with the terminal 4, the blind hole 7, the counter element 8 and the metal substrate structure 3. For example, the ultrasonic welding process is carried out at an ultrasonic frequency in the range of 10-100kHz (e.g., 20kHz). For example, the ultrasonic welding process is carried out at an amplitude of 10μm to 100μm. The ultrasonic welding process can be carried out under a predetermined mechanical pressure of 100N to 1000N acting on the terminal foot 42.

[0051] In addition, the laser welding process can be configured to provide specific parameters to beneficially affect the formation of one or more welded joints. Therefore, the laser beam 60 or the corresponding laser source for laser welding can be configured to provide a power of 300-3000W. Alternatively or additionally, the laser beam or laser source for laser welding can be configured to provide a moving speed of 1-200mm / s guided along the top surface 43 of at least one terminal 4 facing the incident laser beam 60. Therefore, welding does not have to be performed only at a limited point, and the laser spot of the laser beam providing the welding process can be moved at the above speed to provide a joint connection within a limited area. There can also be multiple small laser spots for joint connection. The laser beam 60 can also be configured to oscillate at a predetermined frequency. Therefore, the laser spot position can oscillate or swing at a frequency of up to 2kHz. This swing can be presented as an oscillation of the irradiation point position to prevent excessive local heating, and can occur together with the above-mentioned laser movement to beneficially affect the welding process.

[0052] The embodiments described relate to ultrasonic welding and / or laser welding of power and auxiliary terminals 4 on an insulated metal substrate or insulated metal substrate implemented by a metal substrate structure 3. The insulated metal substrate can be prepared by lamination or molding technology. Substrate structures based on alternative insulated metal substrate technologies (such as stamped and molded metal substrates) are also feasible. The ultrasonic welding and / or laser welding process is facilitated by blind holes 7 passing through the metal bottom layer 19 and the isolation layer 18 of the metal substrate structure 3.

[0053] Embodiments of the method for attaching terminals 4 and / or manufacturing a metal substrate structure 3 having one or more attached terminals 4 can reduce the risk of crack formation or damage in the isolation layer 18 by reducing thermal, mechanical and / or thermomechanical influences on the substrate structure. Therefore, due to the method, a stable semiconductor power module 10 is feasible, which can achieve reliable operation even in high voltage power module applications (e.g., in the voltage range of 0.5 kV to 10.0 kV).

[0054] Figures 1 to 4 The embodiments shown represent exemplary embodiments of the improved metal substrate structure 3, semiconductor power module 10 and methods of manufacturing the same; therefore, they do not constitute a complete list of all embodiments. For example, the actual arrangement and method may be different from the embodiments shown in terms of the metal substrate structure 3 and the semiconductor power module 10.

[0055] Reference numerals

[0056] 3 Metal substrate structure

[0057] 4 terminals

[0058] 41 Terminal body

[0059] 42 terminal pins

[0060] 43 Top surface of terminal pin

[0061] 44 The bottom surface of the terminal pin

[0062] 45 terminal pin solder connection

[0063] 5 First coating

[0064] 6 Ultrasonic welding head (not shown)

[0065] 60 Laser beam (not shown)

[0066] 7 Blind holes

[0067] 8 Opposing elements

[0068] 9 Second coating

[0069] 10Semiconductor power module

[0070] 12 Filling materials

[0071] 17 Metal Top Layer

[0072] 171 Unsupported section of metal top layer

[0073] 18 Isolation Layer

[0074] 19 Metal base

[0075] A Stacking direction

[0076] B Horizontal direction

[0077] d_bh is the circumscribed diameter of the blind hole

[0078] d_wc The diameter of the circumscribed circle of the soldered connection of the terminal pin

[0079] S(i) Steps of a method for manufacturing a metal substrate structure for a semiconductor power module

Claims

1. A method for attaching a terminal (4) to a metal substrate structure (3) for a semiconductor power module (10), comprising: - providing at least one terminal (4), - providing the metal substrate structure (3), the metal substrate structure having: - a metallic top layer (17), - a metal substrate (19) and - an isolating layer (18) arranged between the metal top layer (17) and the metal bottom layer (19), - providing at least one blind hole (7) passing through the metallic base layer (19) and the isolation layer (18), - wherein the at least one terminal (4) is positioned on the metal top layer (17) opposite the blind hole (7), and - coupling said at least one terminal (4) to said metal top layer (17) by means of welding.

2. The method according to claim 1, wherein: - The welding method is ultrasonic welding using an ultrasonic welding head (6).

3. The method according to claim 1, wherein: - The welding method is laser welding using a laser beam (60).

4. A method according to any one of the preceding claims, wherein: - During welding, a counter-element (8) is introduced into the blind hole (7).

5. A method according to any one of the preceding claims, wherein: After welding has been completed, the at least one blind hole (7) is at least partially filled with a filling material (12) comprising an electrically insulating material.

6. A method according to any one of the preceding claims, wherein: - said filling of said blind hole (7) is done by dispensing or injecting said filling material (12).

7. A semiconductor power module (10), comprising: - at least one metal substrate structure (3), said at least one metal substrate structure comprising a metal top layer (17), a metal bottom layer (19) and an isolation layer (18), - at least one terminal (4), - at least one blind hole (7) passing through the metallic base layer (19) and the isolation layer (18), and - wherein the at least one terminal (4) is positioned on the metal top layer (17) opposite to the blind hole (7) and is coupled by welding means.

8. The semiconductor power module (10) according to claim 7, wherein the terminal (4) comprises: - a terminal body (41) and - a terminal foot (42) coupled to the terminal body (41) in an L-shape or a U-shape substantially perpendicular to the terminal body (41).

9. The semiconductor power module (10) according to claim 8, wherein: - The circumscribed circle diameter (d_wc) of the welding connection portion (45) of the terminal foot (42) is smaller than or equal to the circumscribed circle diameter (d_bh) of the blind hole (7).

10. The semiconductor power module (10) according to any one of claims 7 to 9, wherein: - The terminal foot (42) has a thickness of 0.25 mm to 2.0 mm.

11. The semiconductor power module (10) according to any one of claims 7 to 10, wherein: - The metal top layer (17) has a thickness of 150 μm to 500 μm.

12. The semiconductor power module (10) according to any one of claims 7 to 11, wherein: - The isolation layer (18) has a thickness of 100 μm to 200 μm.

13. The semiconductor power module (10) according to any one of claims 7 to 12, wherein: - The isolation layer (18) is made of resin material.

14. The semiconductor power module (10) according to claim 13, wherein: - The resin material used for the isolation layer (18) is a thermosetting resin containing a thermally conductive filler material.

15. The semiconductor power module (10) according to any one of claims 7 to 14, wherein: - The terminal pins (42) are welded to the metal top layer (17) by ultrasonic welding, laser welding or other suitable welding methods.

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