Molded body having a crack-inhibiting design, and method for producing the molded body having a crack-inhibiting design
Patent Information
- Application Number
- PCT/EP2026/054099
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-02-19
- Filing Date
- 2026-02-16
- Publication Date
- 2026-08-27
Smart Images
Figure EP2026054099_27082026_PF_FP_ABST
Abstract
Description
[0001] R.417458
[0002] - 1 -
[0003] Description
[0004] title
[0005] Mold body in crack-resistant design and method for manufacturing the mold body in crack-resistant design
[0006] Technical field
[0007] The invention relates to a mold body in a crack-resistant configuration for at least partially enclosing a power module. Furthermore, the invention relates to a method for producing a mold body in a crack-resistant configuration, designed for at least partially enclosing a power module.
[0008] State of the art
[0009] In conventional power modules with a molded body, this serves as a supporting element to ensure mechanical stability, electrical insulation, increased service life, and protection against external influences. Molded bodies typically feature integrated external contact areas, designed, for example, as recesses or features to facilitate connection with external electrical contacts. However, designs with integrated external contact areas often have disadvantages, particularly regarding mechanical failure and insufficient electrical reliability.
[0010] During the manufacturing process, stresses are generated in the area of external contacts. This is caused by material shrinkage during the curing of the molding material or by uneven pressure conditions during the injection molding process. Due to the geometry of the mold, stress concentrations occur, which lead to the formation of microcracks (R.417458).
[0011] - 2 -
[0012] This is particularly critical at sharp edges or corners of molded external contact areas.
[0013] Furthermore, the mold body is exposed to thermal and mechanical stresses during operation, such as temperature fluctuations or vibrations. The external contact areas represent weak points in this context. Stress concentrations occur at these external contact areas, which in turn lead to the formation or propagation of cracks.
[0014] Cracks in the external contact areas compromise the integrity of the entire power module. This allows moisture or contaminants to penetrate, damaging the internal components. This affects both the electrical insulation and the mechanical stability of the power module. Furthermore, it leads to a deterioration in heat dissipation, which in turn negatively impacts reliability and lifespan.
[0015] Disclosure of the invention
[0016] According to the invention, a mold body with crack-resistant design is proposed for at least partially enclosing a power module. The mold body has at least one external contact area with a laser-treated section, and this external contact area has a drain pad opening with a stepped structure. The drain pad opening has a notch base with a passage for contacting an external contact element with the power module, and a first stage and at least one intermediate stage. The first stage and the at least one intermediate stage are arranged between a side wall of the drain pad opening and the notch base, and the at least one intermediate stage is directly adjacent to the notch base. The external contact area is designed such that crack formation is reduced in at least one critical area.
[0017] A mold body proposed according to the invention is a potting compound whose purpose is to protect and adequately insulate electronic components, such as power modules. The mold body is manufactured according to R.417458.
[0018] - 3 -
[0019] For example, from epoxy resin or silicone, or alternatively from materials that offer both electrical insulation and mechanical stability. The mold body proposed according to the invention at least partially encloses a power module and has at least one external contact area for external contacting.
[0020] A power module is an electronic assembly used in various applications, such as power electronics, drive technology, and electric vehicle technology. A power module typically comprises at least one primary substrate, such as an AMB substrate (AMB: Active Metal Brazing), and at least one secondary substrate, such as a DBC substrate (DBC: Direct Bonded Copper), as well as at least one semiconductor device and a drain pad area. The drain pad area is a defined surface area of the power module on the DBC substrate where a drain potential is applied to the underside of the semiconductor device, establishing an electrical connection via wire bonding. The AMB substrate is connected to a drain pad of the DBC substrate, allowing a potential to be tapped and used for external contacting.This allows for reliable control of the semiconductor component. The drain pad can be, for example, a copper plate, while the external contact element can be a flexible film or a pin.
[0021] The solution according to the invention leads to a reduction in stresses at at least one crack initiation position, resulting in improved load-bearing capacity of the mold body. The mold body, which at least partially encloses a power module, is protected by a reduction in stress-induced loads at at least one external contact area, leading to an increased service life of the power module. This, in turn, prevents crack formation in the mold body during mechanical and / or thermal stress.
[0022] An end region, such as a DBC ceramic edge, of the DBC substrate can be cited as an example of such a crack initiation location. The end region of the DBC substrate may, for example, exhibit a curvature of the mold body along the surface. For example, the curvature of the mold body in the activated operating mode of the power module R.417458
[0023] - 4 -
[0024] This occurs due to the lower effective coefficient of thermal expansion of the power module compared to the cooler.
[0025] According to the invention, the external contact area is an area incorporated into the mold body for contacting external contact elements. The external contact area, according to the invention, comprises a drain pad opening and a laser-treated area with a stepped structure comprising a first stage and at least one intermediate stage. The stepped structure is generated, for example, by a multi-stage laser treatment. The intermediate stage is advantageously designed such that stresses on the mold body, and in particular at the crack initiation point, are reduced or avoided.
[0026] In a further development of the mold body proposed according to the invention, the laser-treated area comprises the first stage and at least one intermediate stage.
[0027] Advantageously, the first stage and the at least one intermediate stage have a common first depth in the range of 150 to 500 pm, preferably 150 to 250 pm, particularly preferably 200 pm.
[0028] Advantageously, at least one intermediate step is defined by a step width and step height. The step width is at least 150 pm and the step height at most 140 pm.
[0029] In a further embodiment of the mold body proposed according to the invention, the step size is in a range of 100 to 400 pm, preferably 150 to 250 pm, particularly preferably 200 pm.
[0030] Advantageously, the step height is in a range of 50 to 175 pm, preferably from 75 to 140 pm, and particularly preferably from 100 pm.
[0031] The intermediate stage is defined by a step width w and a step height h. The stress in the notch base of the drain pad opening decreases as the step height and step width decrease. The first stage is defined by the height, the width B, and the radius of curvature R relative to the drain pad opening wall, which rises towards the top of the mold body at a predetermined slope. For example, for a specified opening width of R.417458
[0032] - 5 -
[0033] Drain pad opening of 2.5 - 4 mm (measured, for example, on the underside of the drain pad opening, which is at the level of the DBC surface), ensuring that with a step height of less than 140 pm and a step width greater than 150 pm, an advantageous safe range for the lifetime of the mold body is guaranteed.
[0034] Furthermore, it was determined by example calculations that when the intermediate stage according to the invention, the step height of 100 pm and the step width of 200 pm, is introduced, the service life of the mold body is increased by at least a factor of 3.
[0035] In a further embodiment of the mold body proposed according to the invention, the first stage has a width of at least 50 pm and a radius of curvature of at least 0.1 mm at a transition point to the side wall of the drain pad opening.
[0036] In a further embodiment of the mold body proposed according to the invention, the intermediate stage has at least one highly stressed edge and at least one slightly stressed edge. A laser depression area is formed on at least one slightly stressed edge, with a laser depression depth of less than 300 pm.
[0037] Furthermore, a method for producing a mold body in a crack-resistant design, designed to at least partially enclose a power module, is proposed.
[0038] The procedure includes:
[0039] (a) Providing a performance module,
[0040] (b) Molds of the power module,
[0041] (c) Providing at least one external contact area, the provision comprising at least the following steps:
[0042] i. Creating a first depression, wherein the first depression has a laser processing area,
[0043] ii. Creating a first stage on the laser processing area by a first laser treatment, R.417458
[0044] - 6 -
[0045] iii. Creating an intermediate stage by a second laser treatment on the first stage, creating a drain pad opening, wherein step iii) is repeatable to create a variety of intermediate stages and
[0046] iv. Creating a passage at the notch base of the drain pad opening for contacting an external contact element with the power module.
[0047] The first laser treatment and the second laser treatment proceed in a direction that extends parallel to a highly stressed edge.
[0048] Method according to claim 9, wherein the laser processing area has a material depth in a range of 150 to 1000 pm, preferably 250 to 650 pm, particularly preferably 400 pm.
[0049] Furthermore, it must be considered that the direction of the first and second laser treatments must be selected depending on the stresses. If the laser is continuously activated during the first and / or second laser treatment, depressions or so-called "laser depressions" are induced at the laser's reversal points. These depressions result from longer dwell times of the laser at these points. These depressions, also referred to as "laser depressions," lead to an increase in stress. For this reason, the laser direction is chosen to be parallel to the highly stressed edge, so that the reversal points lie opposite the highly stressed edge. Consequently, the laser treatment does not result in the formation of ideal steps at the highly stressed edges, but rather in wavy steps, which include a first step and at least one intermediate step without laser depressions.Laser depressions are formed at the edges subject to low stress, where the reversal points of the first and / or second laser treatment are located. A maximum depth of 300 pm is required for these laser depressions. Preferably, the laser properties, such as power or feed rate, are adjustable accordingly.
[0050] Advantages of the invention R.417458
[0051] - 7 -
[0052] The solution according to the invention advantageously achieves a crack-resistant design of the external contact areas of a mold body in a power module, which includes at least one intermediate stage. This intermediate stage advantageously ensures a uniform stress distribution and minimizes mechanical weak points at a drain pad opening, which occur at the particularly stressed edges.
[0053] The design of at least one intermediate stage also contributes to making the mold body more resistant to mechanical and thermal stresses during operation and reduces local stress concentrations caused by temperature fluctuations or mechanical vibrations. This stress reduction effectively inhibits the formation and growth of cracks, thereby significantly increasing the reliability and service life of the power module.
[0054] Brief description of the drawings
[0055] Embodiments of the invention are explained in more detail with reference to the drawings and the following description.
[0056] They show:
[0057] Figure 1 is a schematic representation of a mold body,
[0058] Figure 2 shows a schematic representation of a power module,
[0059] Figure 3 shows a schematic partial representation of the mold body with power module in frontal section,
[0060] Figure 4.1 shows a perspective view of a potential crack in a structure constructed according to the state of the art.
[0061] External contact area, R.417458
[0062] - 8 -
[0063] Figure 4.2 shows a schematic representation of an external contact area constructed according to the state of the art in perspective cross-section.
[0064] Figure 5 shows a schematic representation of an external contact area with an intermediate stage.
[0065] Figure 6.1 shows a schematic sectional view of the external contacting area with the intermediate stage in cross-section AA in perspective.
[0066] Figure 6.2 shows a schematic sectional view of the external contacting area with the intermediate stage in cross-section AA.
[0067] Figure 6.3 shows a schematic sectional view of the external contacting area with the intermediate stage with dimensions in cross-section AA.
[0068] Figure 7.1 shows a graphical representation of the dependence of a relative change in stress,
[0069] Figure 7.2 shows a graphical representation of the dependence of a relative change in lifetime.
[0070] Figure 8 is a graphical representation of a stress field diagram around a highly stressed edge in relation to the direction of the laser.
[0071] Figure 9 shows a schematic representation of a laser guide.
[0072] Figure 10.1 shows a schematic representation of the highly stressed edge,
[0073] Figure 10.2 shows a schematic representation of a real laser structure at the highly stressed edge and
[0074] Figure 11 shows a schematic representation of a laser depression and a real laser structure on a lightly stressed edge. R.417458
[0075] - 9 -
[0076] Embodiments of the invention
[0077] In the following description of embodiments of the invention, identical or similar elements are designated by the same reference numerals, and repeated descriptions of these elements are omitted in individual cases. The figures represent the subject matter of the invention only schematically.
[0078] Figure 1 shows a schematic representation of a mold body 10. The mold body 10 shown has two external contact areas 12. The external contact areas 12 are arranged adjacent to each other and separated from one another on a top surface 11 of the mold body 10. The external contact areas 12 are further configured such that an at least partially enclosed power module 14 (shown in Figure 2), in particular a drain pad DBC substrate 28 (shown in Figure 2) of the power module 14, can be electrically contacted by at least one external contact element through the external contact areas 12. The external contact element can be, for example, a cable or a pin.
[0079] Figure 2 shows a schematic representation of the power module 14. The power module 14 comprises an AMB substrate 24, two DBC substrates 28, a temperature sensor C.NTC" 18, and eight semiconductor devices 20. The AMB substrate 24 has conductor structures 21 and an electrical insulation layer. The conductor structures 21 are electrically isolated from each other and arranged substantially symmetrically. The AMB substrate 24 is essentially a support substrate. The semiconductor devices 20, which can be, for example, transistors, MOSFETs, IGBTs, diodes, or other semiconductor devices used, for example, as semiconductor switches, are arranged on the conductor structures 21.The DBC substrate 28, for example, consists of a ceramic substrate, such as aluminum oxide or aluminum nitride, and a copper layer bonded directly to it, which ensures the electrical contact of the semiconductor devices 20 in the power module 14. The DBC substrate 28 also has drain pad areas 16, each of which has a drain pad 40 arranged on it. The semiconductor devices 20 and the drain pads 40 are R.417458.
[0080] - 10 -
[0081] each is electrically connected to each other, for example, via at least one bond wire 22.
[0082] Figure 3 shows a schematic partial view of the mold body 10 with power module 14 in a frontal section. Figure 3 also shows the power module 14, which is arranged on a cooler 15 and is at least partially enclosed. The power module 14 comprises an AMB substrate 24 and a DBC substrate 28. Furthermore, it can be seen from the power module 14 shown in Figure 3 that the power module 14 includes semiconductor devices 20 arranged on the AMB substrate, on each of which spacers 38 are positioned. The DBC substrate 28 is in turn positioned on the spacers 38. A drain pad 40 is arranged on a DBC substrate surface 29 in the drain pad area 16, which is located directly below the external contact area 12. This ensures contact between an external contact element and the drain pad 40. The drain pad 40 is made of a conductive material, such as copper 46.
[0083] The exemplary cooler 15 shown in Figure 3 has a base plate 30, a deep-drawn channel section 32, a turbulator 34, and a stiffening plate 36. A connection between the cooler 15 and the mold body 10 can be made, for example, by using a cold-sprayed copper 44 and a base plate solder 42.
[0084] Figure 4.1 shows a perspective view of a potential crack 52 at an external contact area 12 within the mold body 10, designed according to the prior art. It can be seen that, according to the prior art, the external contact area 12 is formed in a single stage on the underside and includes a laser-treated area 48. Furthermore, Figure 4.1 shows that, according to the prior art, the external contact area 12 has a passage 45 at its lower end for contacting the DBC substrate 28, in particular the drain pad 40, for example made of copper 46.
[0085] Figure 4.2 shows a schematic representation of an external contact area 12 designed according to the prior art within the mold body 10 in a longitudinal section through the external contact area 12. It can be seen that the external contact area 12 is designed according to R.417458
[0086] - 11 -
[0087] The prior art design features a single-stage underside with a laser-treated area 48. Furthermore, Figure 4.2 shows that the outer contact area 13, according to the prior art, has a passage 45 at its lower end for contacting the DBC substrate 28, in particular the drain pad 40, for example made of copper 46. Figure 4.2 also shows that the crack 52 is initiated at a crack initiation position 50 along the notch root 47 on the inner edge of the step at the level of a DBC ceramic edge 60.
[0088] Figure 5 shows a schematic representation of the external contact area 12 with an intermediate stage 68. Figure 5 illustrates the external contact area 12, which is formed in a mold body 10 that at least partially encloses a power module 14. The external contact area 12 is configured as a drain pad opening 39. This opening features the laser-treated area 48 with the notch base 47. The notch base 47 has a through-hole 45. The through-hole 45 is designed for contacting the DBC substrate 28, in particular the drain pad 40, which is formed, for example, from copper 46. A first stage 54 and an intermediate stage 68 are formed in the lower region of the drain pad opening 39. The first stage 54 borders the intermediate stage 68 and the transition area 57 to the side wall 55 of the drain pad opening 39, and the intermediate stage 68 borders the first stage 54 and the notch base 47.
[0089] Figure 6.1 shows a schematic sectional view of the external contact area 12 with the intermediate stage 68 in cross-section AA in perspective. A portion of the mold body 10, which at least partially encloses a power module 14, is visible in Figure 6.1. The external contact area 12 is designed as a drain pad opening 39. This opening features the laser-treated area 48 with the notch base 47. The first stage 54 and the intermediate stage 68 are formed in the lower region of the drain pad opening 39. The first stage 54 borders the intermediate stage 68 and the transition area 57 to the side wall 55 of the drain pad opening 39, and the intermediate stage 68 borders the first stage 54 and the notch base 47.
[0090] Figure 6.2 shows a schematic sectional view of the external contacting area 12 with the intermediate stage 68 in cross-section AA inR.417458
[0091] - 12 -
[0092] An enlarged view is shown. Figure 6.2 depicts a portion of the mold body 10, which at least partially encloses a power module 14. The external contact area 12 is designed as a drain pad opening 39. This opening features the laser-treated area 48 with the notch base 47. The first stage 54 and the intermediate stage 68 are formed in the lower region of the drain pad opening 39. The first stage 54 borders the intermediate stage 68 and the transition area 57 to the side wall 55 of the drain pad opening 39, and the intermediate stage 68 borders the first stage 54 and the notch base 47.
[0093] Figure 6.3 shows a schematic sectional view of the external contact area 12 with the intermediate step 68, with dimensions in cross-section AA. Accordingly, a portion of the external contact area 12, including the notch root 47 and the laser-treated area 48 on the mold body 10, can be seen in Figure 6.3. Furthermore, the first step 54 and the intermediate step 68 can be seen in Figure 6.3. The first step 54 borders the intermediate step 68 and the transition area 57 to the side wall 55 of the drain pad opening 39, and the intermediate step 68 borders the first step 54 and the notch root 47. The intermediate step 68 is defined by a step width 72 and a step height 74 such that the stress in the notch root 47 of the drain pad opening 39 is lower the smaller the step height 74 and the larger the step width 72. The first stage 54 is defined by the height 66, the width 70 and the radius of curvature 76 to the side wall 55.For example, if the opening width of the drain pad opening 39 is set to be 2.5 to 4 mm (measured, for example, on the underside of the drain pad opening 39, which is at the level of the DBC surface), then for a step height 74 less than 140 pm and a step width 72 greater than 150 pm, an advantageous safe area 80 (shown in Figure 7.1) is ensured for a lifetime of the mold body 10.
[0094] Figure 7.1 shows a graphical representation of the dependence of a relative stress change 82 on the step width 72 and the step height 74 of an intermediate step 68. The step width 72 is shown on a vertical axis, while the step height 74 is plotted on a horizontal axis.
[0095] Within Figure 7.1, a safe area 80 is indicated by a dashed line. This safe area 80 comprises pairs of values of step size 72 and step height 74, where the relative voltage change 82 within R.417458
[0096] - 13 -
[0097] within an acceptable range. The transitions between the safe range 80 and the zones with critical stress changes are represented by shades of gray, indicating a continuous gradation. The shades are visualized by dots, with dot density representing the intensity of the stress change. Areas with a smaller stress change are thus represented by dots spaced further apart, while in areas with a more pronounced stress change, the dots are closer together. The dot density increases with increasing distance from the safe range 80 to illustrate a growing deviation from the permissible stress changes. In addition to the graphical representation in Figure 7.1, a vertical bar is shown, displaying the gradations of the relative stress change 82 in shades of gray.This bar serves to visually identify the value ranges and indicates the intensity of the changes according to a shading.
[0098] Figure 7.2 shows a graphical representation of the dependence of a relative change in lifetime 84 on the step width 72 and the step height 74 of an intermediate step 68. The step width 72 is shown on a vertical axis, while the step height 74 is plotted on a horizontal axis.
[0099] Within Figure 7.1, a safe area 80 is indicated by a dashed line. This safe area 80 comprises pairs of values of step size 72 and step height 74 where the relative change in lifetime 84 lies within an acceptable range. The transitions between the safe area 80 and the zones with critical changes in lifetime are represented by shades of gray, indicating a continuous gradation. The shades of gray are represented by dots, with dot density reflecting the intensity of the change in lifetime. Areas with critical changes in lifetime are represented by dots spaced further apart, while in areas with permissible changes in lifetime, the dots are closer together. With increasing distance from the safe area 80, the dot density decreases to illustrate an increasing deviation from the permissible changes in lifetime. In addition to the graphical representation in Figure 7.Figure 2 shows a vertical bar depicting the gradations of the relative lifetime change 84 in grayscale. This bar serves to visually identify the value ranges and indicates the intensity of the changes according to the shading. R.417458.
[0100] - 14 -
[0101] Figure 8 shows a schematic representation of an exemplary highly stressed edge 88 in conjunction with laser treatment, where the stress change is depicted in grayscale and with numerical values in different areas of the drain pad opening 39. Figure 8 also shows a structured surface with a highly stressed edge 88 subjected to stresses due to loading. Along the highly stressed edge 88, the stress changes in different areas are shown as grayscale. The greatest stress change is shown at the highly stressed edge 88 itself, with this area highlighted by the darkest grayscale. This area exhibits the highest stress value, which is shown as a numerical value directly next to the highly stressed edge 88. With increasing distance from the highly stressed edge 88 along the surface, the stress changes decrease.The stress values in these areas are also entered as numerical values on the respective surface, decreasing with increasing distance from the highly stressed edge 88. This decrease in stress changes is represented by a lightening of the grayscale levels. The grayscale levels are visualized by dots, with the dot density representing the intensity of the stress change. Areas with a lower stress change are therefore represented by more widely spaced dots, while in areas with a more pronounced stress change, the dots are arranged closer together. The diagram includes a grayscale bar that represents the stress change in relation to the grayscale levels. The darkest areas of the bar represent the highest stress changes, while the lighter areas indicate lower stress changes.
[0102] Figure 9 shows a schematic representation of a laser guide during the process for manufacturing mold bodies 10 with crack resistance. A partially depicted mold body 10 with the external contact area 12, which is designed as a drain pad opening 39, can be seen in Figure 9. Furthermore, the notch base 47 with the through-hole 45 can be seen in Figure 9. The through-hole 45 can be produced, for example, by a laser in the process for manufacturing mold bodies 10. The through-hole 45 is realized such that the DBC substrate R.417458
[0103] - 15 -
[0104] 28, in particular drain pad 40, for example made of copper 46, is exposed for electrical contact.
[0105] Figure 9 shows a schematic representation of a laser guide during the process for manufacturing mold bodies 10 with crack resistance. Figure 9 shows that the mold body 10 has a partially depicted external contact area 12, which is configured as a drain pad opening 39. Figure 9 also shows the notch base 47 with the through-hole 45. The through-hole 45 can be produced, for example, by laser treatment. The through-hole 45 is designed such that the DBC substrate 28, in particular the drain pad 40, is exposed for electrical contact.
[0106] Furthermore, Figure 9 shows the laser-treated area 48, which is created by a first and second laser treatment to form the first stage 54 and the intermediate stage 68. Figure 9 also illustrates the direction of the laser's path during the first and second laser treatments, indicated by a dashed line. The laser's starting point 89 is located in a corner of the first stage 54 or the intermediate stage 68. The laser removes the mold material in the longitudinal direction 87.1 until a first stage 54 or intermediate stage 68 is formed. A laser reversal position 86 is located at the edge in the transverse direction 87.2, thus preventing a laser depression 94 (shown in Figure 11) at the edge in the longitudinal direction 87.1.
[0107] Figure 10.1 is a schematic representation of the highly stressed edge 88. Figure 10.1 also shows the external contact area 12 with the intermediate step 68 in a cross-section AA in perspective. Furthermore, a portion of the mold body 10, which at least partially encloses a power module 14, can be seen in Figure 10. The external contact area 12 is designed as a drain pad opening 39. This opening has the laser-treated area 48 with the notch base 47. The first step 54 and the intermediate step 68 are formed in the lower region of the drain pad opening 39. The first step 54 borders the intermediate step 68 and the transition area 57 to the side wall 55 of the drain pad opening 39, and the intermediate step 68 borders the first step 54 and the notch base 47. Furthermore, a slightly stressed edge 92 can be seen in Figure 10.1. R.417458
[0108] - 16 -
[0109] Figure 10.2 shows a schematic representation of an exemplary real laser structure 98 at the highly stressed edge 88. Figure 10.2 also shows an enlarged schematic cross-sectional view of the external contacting area 12 with the intermediate stage 68 in cross-section AA. Furthermore, a portion of the external contacting area 12 with the notch root 47 and the laser-treated area 48 on the mold body 10 can be seen in Figure 10.2. The first stage 54 and the intermediate stage 68 are also shown in Figure 10.2. The first step 54 borders the intermediate step 68 and the transition area 57 to the side wall 55 of the drain pad opening 39, and the intermediate step 68 borders the first step 54 and the notch base 47. The first step 54 and intermediate step 68 shown in Figure 10.2 are located in the longitudinal direction 87.1 along the highly stressed edge 88.
[0110] Figure 11 shows a schematic representation of a laser depression 94 and a real laser structure 98 on a lightly stressed edge 92. Figure 11 also shows an enlarged schematic cross-sectional view of the external contact area 12 with the intermediate step 68 in cross-section AA. A portion of the external contact area 12 with the notch root 47 and the laser-treated area 48 on the mold body 10 can be seen in Figure 11. Furthermore, the first step 54 and the intermediate step 68 can be seen in Figure 11. The first step 54 borders the intermediate step 68, which in turn borders the first step 54 and the notch root 47. The first stage 54 and the intermediate stage 68 shown in Figure 11 lie in the transverse direction 87.2 along the slightly stressed edge 92. In addition, a laser depression 94 at the end of the intermediate stage 68 at the notch base 47 can be seen in Figure 11, which has a laser depression depth 96.The laser indentation 94 is created during the generation of the intermediate stage 68 by the laser reversal position 86, due to a longer dwell time at the less stressed edge 92 compared to the dwell time at the highly stressed edge 88.
[0111] The invention is not limited to the embodiments described here and the aspects highlighted therein. Rather, within the scope specified by the claims, a multitude of modifications are possible that fall within the bounds of what is considered skilled in the art.
Claims
R.417458 - 17 - Claims 1. Mold body (10) in a crack-resistant configuration for at least partially enclosing a power module (14), wherein the mold body (10) has at least one external contact area (12) with a laser-treated area (48) and the at least one external contact area (12) has a drain pad opening (39) with a stepped structure, wherein the drain pad opening (39) has a notch base (47) with a passage (45) for contacting an external contact element with the power module (14) and a first stage (54) and at least one intermediate stage (68), and the first stage (54) and the at least one intermediate stage (68) are arranged between a side wall (55) of the drain pad opening (39) and the notch base (47), and the at least one intermediate stage (68) is directly adjacent to the notch base (47), wherein the at least one external contact area (12) is designed such that crack formation in at least one critical area is reduced 2. Mold body (10) according to claim 1, wherein the laser-treated area (48) comprises the first stage (54) and the at least one intermediate stage (68).
3. Mold body (10) according to claim 1 or 2, wherein the first stage (54) and the at least one intermediate stage (68) have a common first depth (56) in a range of 150 to 500 pm, preferably 150 to 250 pm, particularly preferably 200 pm.
4. Mold body (10) according to one of the preceding claims, wherein the at least one intermediate stage (68) is defined by a step width (72) and step height (74), wherein the step width (72) is at least 150 pm and the step height (74) is at most 140 pm. R.417458 - 18 - 5. Mold body (10) according to claim 4, wherein the step width (72) is in a range of 100 to 400 pm, preferably 150 to 250 pm, particularly preferably 200 pm.
6. Mold body (10) according to claim 5 or 4, wherein the step height (74) is in a range of 50 to 175 pm, preferably 75 to 140 pm, particularly preferably 100 pm.
7. Mold body (10) according to one of the preceding claims, wherein the first stage (54) has a width (70) of at least 50 pm and a radius of curvature (76) of at least 0.1 mm at a transition area (57) to the side wall (55) of the drain pad opening (39).
8. Mold body (10) according to one of the preceding claims, wherein the intermediate stage (68) has at least one highly stressed edge (88) and at least one low-stressed edge (92), wherein a laser depression area (90) is formed on at least one low-stressed edge (92), wherein a laser depression depth (96) of the laser depression area (90) is less than 300 pm.
9. Method for producing a mold body (10) in a crack-resistant design, configured to at least partially enclose a power module (14), wherein the method comprises: (a) Provision of a performance module (14), (b) Molds of the power module (14), (c) Providing at least one external contacting area (12), wherein the provisioning comprises at least the following steps: i. generating a first depression, wherein the first depression has a laser processing area, ii. generating a first step (54) on the laser processing area by a first laser treatment, iii. generating an intermediate step (68) by a second laser treatment on the first step (54), wherein a drain pad opening (39) is generated, wherein step iii)R.417458 - 19 - is repeatable to generate a multitude of intermediate stages (68) and iv. Creating a passage (45) at the notch base (47) of the drain pad opening (39) for contacting an external contact element with the power module, wherein the first laser treatment and the second laser treatment are carried out in a direction extending parallel to a highly stressed edge (88).
10. Method according to claim 9, wherein the laser processing area has a material depth in a range of 150 to 1000 pm, preferably 250 to 650 pm, particularly preferably 400 pm.