Method for opening a power module

Abstract

The application discloses a method for opening a power module, the power module comprising a mold sealing body, a chip and a heat dissipation substrate, the chip being located in the mold sealing body, the chip and the heat dissipation substrate being stacked along a first direction from a front surface to a back surface of the mold sealing body, the heat dissipation substrate comprising a first conductive layer, a ceramic layer and a second conductive layer stacked along the first direction, the method comprising the following steps: obtaining position information of the first conductive layer and / or the ceramic layer in the first direction; based on the position information, performing a first cutting step from a side surface of the mold sealing body along a second direction perpendicular to the first direction to remove the second conductive layer and at least part of the ceramic layer; and polishing the cut power module to expose the chip. The application can remove the second conductive layer and at least part of the ceramic layer by means of lateral cutting, can significantly reduce the polishing workload, improve the opening efficiency, and reduce the material cost.

Description

Technical Field

[0001] This invention relates to the field of semiconductor device testing, and in particular to a method for unpacking a power module. Background Technology

[0002] Before performing failure analysis on a chip, the power module usually needs to be unpacked to remove the mold, heat sink, and other structures. The traditional unpacking method is to polish the power module with sandpaper. However, the ceramic layer in the heat sink is hard, making sandpaper polishing difficult, time-consuming, inefficient, and requiring a large amount of sandpaper, resulting in high material costs. Summary of the Invention

[0003] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a method for unpacking power modules that can ensure detection accuracy and improve detection efficiency.

[0004] According to an embodiment of the present invention, a method for opening a power module is applied to a power module, the power module including a mold body, a chip and a heat dissipation substrate, the chip being located within the mold body, the mold body including a first surface and a second surface disposed opposite to each other, the chip and the heat dissipation substrate being stacked along a first direction from the first surface to the second surface, the heat dissipation substrate including a first conductive layer, a ceramic layer and a second conductive layer being stacked along the first direction, wherein the first conductive layer and the ceramic layer are located within the mold body, the second conductive layer is partially located within the mold body, and the surface of the second conductive layer facing away from the ceramic layer is exposed from the second surface;

[0005] The method for opening the power module includes the following steps:

[0006] Obtain the position information of the first conductive layer and / or the ceramic layer in the first direction;

[0007] Based on the location information, a first cutting step is performed from the side of the mold body along a second direction perpendicular to the first direction to remove the second conductive layer and at least a portion of the ceramic layer;

[0008] The cut power module is polished to expose the chip.

[0009] The unpacking method for the power module according to the first embodiment of the present invention has at least the following beneficial effects:

[0010] The present invention can remove the second conductive layer and at least part of the ceramic layer by lateral cutting, which can significantly reduce the amount of polishing work, improve the opening efficiency, and reduce material costs.

[0011] In other embodiments of the present invention, the first cutting step is performed by a cutting tool from the side of the mold body along the second direction;

[0012] The unpacking method for the power module further includes the following steps:

[0013] A first ratio is obtained between the thickness of the cutting tool and the thickness of the first conductive layer. When the first ratio is less than or equal to a first set value, the cutting tool cuts within the range of the first conductive layer to remove the second conductive layer and all of the ceramic layer.

[0014] In other embodiments of the present invention, the first set value is 0.8.

[0015] In other embodiments of the present invention, the unpacking method of the power module further includes the following steps:

[0016] The first cutting step is performed by the tool within the range of the first conductive layer and from the side closest to the ceramic layer.

[0017] In other embodiments of the present invention, the unpacking method of the power module further includes the following steps:

[0018] A second ratio is obtained between the thickness of the cutting tool and the thickness of the ceramic layer. When the first ratio is greater than the first set value and the second ratio is less than or equal to the second set value, the first cutting step is performed by the cutting tool within the range of the ceramic layer to remove the second conductive layer and at least a portion of the ceramic layer.

[0019] In other embodiments of the present invention, the second setting value is 1.

[0020] In other embodiments of the present invention, the unpacking method of the power module further includes the following steps:

[0021] The first cutting step is performed by the tool within the ceramic layer and from the side closest to the first conductive layer.

[0022] In other embodiments of the present invention, the unpacking method of the power module further includes the following steps:

[0023] When the first ratio is greater than the first set value and the second ratio is greater than the second set value, the first cutting step is performed at the junction of the first conductive layer and the ceramic layer by the cutting tool to remove the second conductive layer and all of the ceramic layer.

[0024] In other embodiments of the present invention, the unpacking method of the power module further includes the following steps:

[0025] A second cutting step is performed on the power module along the first direction or in a direction opposite to the first direction to form a cross-section that exposes the first conductive layer, the ceramic layer and the second conductive layer;

[0026] The positional information of the first conductive layer and / or the ceramic layer in the first direction is obtained through the cross-section.

[0027] In other embodiments of the present invention, the unpacking method of the power module further includes the following steps:

[0028] A perspective image of the power module is obtained from one side of the first surface or the second surface. Based on the perspective image, a cutting position for the second cutting step is selected so that the cutting position avoids the chip and passes through the heat dissipation substrate.

[0029] In other embodiments of the present invention, the unpacking method of the power module further includes the following steps:

[0030] A mounting component is provided, the mounting component having a mounting surface, the mounting surface and / or the first surface having a recess;

[0031] An adhesive is applied between the mounting surface and the first surface to press the power module against the mounting component, and the adhesive is heated to fill the recessed portion.

[0032] The adhesive is cooled to bond the power module to the mounting component.

[0033] In other embodiments of the present invention, the first cutting step is performed by a tool from the side of the molded body along the second direction, wherein the unpacking method of the power module includes at least one of the following parameters:

[0034] The thickness of the cutting tool is 0.3 mm to 0.5 mm;

[0035] The feed rate of the tool is 1 mm / min to 2 mm / min.

[0036] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0037] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0038] Figure 1 A schematic diagram illustrating the steps of back-side opening in related technologies;

[0039] Figure 2This is a schematic diagram illustrating the steps of opening the back of the package using the method described in this embodiment of the invention;

[0040] Figure 3 This is a schematic diagram of cutting within the first conductive layer in an embodiment of the present invention;

[0041] Figure 4 This is a schematic diagram illustrating cutting within the ceramic layer in an embodiment of the present invention;

[0042] Figure 5 This is a schematic diagram illustrating the cutting at the junction of the first conductive layer and the ceramic layer in an embodiment of the present invention;

[0043] Figure 6 This is a schematic diagram illustrating the second cutting step of the power module to form a cross-section in an embodiment of the present invention;

[0044] Figure 7 This is a schematic diagram of fixing the power module by mounting component 300 in an embodiment of the present invention.

[0045] Figure label:

[0046] Power module 100, mold body 110, front side 111, back side 112, first recess 113, chip 120, heat dissipation substrate 130, first conductive layer 131, ceramic layer 132, second conductive layer 133;

[0047] 200 cutting tools;

[0048] Mounting component 300, mounting surface 310, second recess 320;

[0049] Adhesive 400. Detailed Implementation

[0050] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0051] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0052] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0053] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0054] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0055] Reference Figure 1 This illustration shows a typical power module to which the present invention applies, comprising a molded body 110, a chip 120, and a heat dissipation substrate 130. The molded body 110 is made of an insulating material such as epoxy resin and is used to construct the insulating protective layer of the power module. The molded body 110 has a first surface and a second surface disposed opposite to each other. In some embodiments, the first surface may be the front surface 111 of the molded body 110, and the second surface may be the back surface 112 of the molded body 110. For ease of description, the direction along the front surface 111 to the back surface 112 is defined as the first direction, and the direction perpendicular to the first direction is defined as the second direction. Figure 1 As shown in the example, the first direction is from top to bottom, and the second direction can be from left to right or from right to left.

[0056] Chip 120 may be a silicon carbide chip, located inside the mold enclosure 110. The heat dissipation substrate 130 is thermally connected to chip 120 for heat dissipation during chip 120 operation. Specifically, chip 120 and heat dissipation substrate 130 are stacked along a first direction, that is, chip 120 is closer to the front side of mold enclosure 110, and heat dissipation substrate 130 is closer to the back side of mold enclosure 110. Chip 120 and heat dissipation substrate 130 are fixedly connected by a sintering layer or a soldering layer, which facilitates the rapid dissipation of heat through heat dissipation substrate 130.

[0057] The heat dissipation substrate 130 includes a first conductive layer 131, a ceramic layer 132, and a second conductive layer 133 sequentially stacked along a first direction. The first conductive layer 131 and the second conductive layer 133 can be made of copper or other materials with electrical and thermal conductivity. Figure 1 As shown, both the first conductive layer 131 and the ceramic layer 132 are located within the mold enclosure 110. The first conductive layer 131 is fixedly connected to the chip 120 by the aforementioned sintering or welding material. The second conductive layer 133 is partially located within the mold enclosure 110. The surface of the second conductive layer 133 facing away from the ceramic layer 132 (e.g., the lower surface in the figure) is exposed from the back side 112 of the mold enclosure 110 to form a heat dissipation surface. For this type of power module, it is usually opened from the back side. It should be noted that in some other embodiments, the first surface can be the back side 112 of the mold enclosure 110, and the second surface can be the front side 111 of the mold enclosure 110. For this type of power module, it can be opened from the front side.

[0058] The steps of the opening method in related technologies are as follows: Figure 1 As shown, the back of the molded body 110 is polished using sandpaper and other polishing tools. While removing the molded body 110, the second conductive layer 133, ceramic layer 132, first conductive layer 131, and solder layer (or sintered layer) are gradually removed until the chip 120 is exposed. Because the ceramic layer 132 has extremely high hardness, the polishing speed is very slow. Therefore, the entire polishing process requires a large amount of manpower and consumes a significant amount of sandpaper, thus increasing material costs. Based on the above problems, this invention proposes a method for opening a power module that can achieve back-side opening of the power module at low cost and high efficiency. The following description, in conjunction with the accompanying drawings and specific embodiments, illustrates this method.

[0059] The embodiments of the present invention are applicable to both back-side opening and front-side opening scenarios. For ease of understanding, subsequent embodiments will be described with the first surface as the front and the second surface as the back. Referring to Figure 2, the relevant steps of the power module opening method in the embodiments of the present invention are shown. Figure 2 The power module in the middle can be referred to Figure 1 Understanding the power module in this embodiment, the difference from the unpacking method in related technologies is that: instead of gradually removing the material from the back side 112 of the mold 110 towards the chip 120, this embodiment cuts from the side of the mold 110 along the second direction, thereby directly removing the second conductive layer 133 and at least part of the ceramic layer 132, and then removing the first conductive layer 131 and the remaining ceramic layer 132 (in some embodiments, the ceramic layer 132 will be completely removed, i.e., ...). Figure 2 As shown in the illustration (in some embodiments there may be a small amount of residue, which will be explained in detail later), routine grinding can remove it, which can significantly reduce the labor and material costs required for opening.

[0060] Specifically, the unpacking method for the power module includes the following steps:

[0061] Step 1: Obtain the position information of the first conductive layer 131 and / or the ceramic layer 132 in the first direction. The position information is used to determine the initial cutting position. Depending on the specific cutting method, some embodiments only require obtaining the position information of the first conductive layer 131, some embodiments only require obtaining the position information of the ceramic layer 132, and some embodiments require obtaining the position information of the first conductive layer 131 and the ceramic layer 132 separately, which will be explained later.

[0062] It should be noted that in this embodiment, the aforementioned position information can be obtained visually (including direct observation and observation through devices such as microscopes), and the cutting device can be positioned to the initial cutting position by combining manual alignment. Alternatively, the aforementioned position information can be obtained through devices such as vision cameras, and the cutting device can be positioned to the initial cutting position by combining automatic alignment.

[0063] Step Two: Based on the position information obtained in Step One, a first cutting step is performed from the side of the mold body 110 along a second direction perpendicular to the first direction to remove the second conductive layer 133 and at least a portion of the ceramic layer 132. It should be noted that the term "second direction perpendicular to the first direction" in this invention is only a general indication of the cutting direction and should not be strictly interpreted as the angle between the first and second directions being exactly 90°. In reality, when the power module is cut using a cutting device such as a tool, the tool's feed trajectory may deviate to some extent due to factors such as tool vibration and uneven cutting forces on both sides. This situation should also be understood as cutting along the second direction.

[0064] Step 3: Grind the cut power module 100 to expose the chip 120. It should be noted that the grinding in this step can be carried out in a conventional way, such as by sanding.

[0065] As mentioned above, the opening method in this embodiment mainly includes a cutting step and a subsequent grinding step. Therefore, the entire opening time is mainly affected by the time consumed by these two steps. Compared with the conventional method of removing material by grinding, this embodiment mainly relies on the rotation of the tool to cut the ceramic, and the cutting time is much shorter than the conventional grinding time. For the subsequent grinding step, depending on the different cutting positions, this embodiment has different residual conditions. In one case, the ceramic layer 132 and the second conductive layer 133 are completely removed, and only the first conductive layer 131 remains on the heat dissipation substrate 130. Since the material hardness of the first conductive layer 131 is much lower than that of ceramic, the grinding time is much shorter than the grinding time of the ceramic layer 132. In another case, the heat dissipation substrate 130 still has the ceramic layer 132 remaining. Since the amount of ceramic layer 132 remaining is small, although its grinding time is slightly increased compared to the previous case, the grinding time is still much shorter than the grinding time of the entire ceramic layer 132. Since the cutting and subsequent polishing steps are both very time-consuming, the overall opening time of this embodiment is much shorter than that required by conventional polishing methods. Through actual operation, the inventors found that for the same power module, opening it using conventional polishing methods takes two days and requires more than six sheets of sandpaper, while the opening method of this embodiment only takes 30 minutes and the sandpaper consumption is minimal. Therefore, the opening cost of power modules can be significantly reduced.

[0066] In some embodiments, the first cutting step is performed by using a cutting tool to cut along a second direction from the side of the molded body 110. The cutting tool can be a disc-shaped tool that is driven to rotate by a drive device such as a motor. During cutting, the edge of the cutting tool is aligned with the initial cutting position on the side of the molded body 110, and the cutting tool is driven to feed along the second direction to perform the first cutting step. Since the thickness of each layer of the heat dissipation substrate 130 is very thin (usually not exceeding 1 mm), the thickness of the corresponding cutting tool will also not exceed 1 mm. If the materials on both sides are inconsistent during cutting, the ultra-thin cutting tool is prone to deviation due to uneven force. For example, when cutting within a sandwich structure formed by metal and ceramic, the reaction force exerted by the metal on the cutting tool 200 is small, while the reaction force exerted by the ceramic on the cutting tool 200 is large. As a result, the cutting tool 200 will deviate towards the metal side. If the deviation is too large, it may cause the cutting tool to jam, and there is also a risk of damaging the chip 120. Based on this, the unpacking method of the power module in this embodiment also includes a step of further determining the initial cutting position to ensure that the cutting tool cuts within the same material as much as possible and reduces deviation.

[0067] Specifically, the unpacking method for the power module in this embodiment further includes the following steps:

[0068] Reference Figure 3Before step two, a first ratio is obtained between the thickness of the tool 200 and the thickness of the first conductive layer 131. When the first ratio is less than or equal to a first set value, the tool 200 performs a first cutting step within the range of the first conductive layer 131. In other words, as long as the first conductive layer 131 has sufficient thickness relative to the tool 200, cutting is preferentially performed within the range of the first conductive layer 131. On the one hand, the material hardness of the first conductive layer 131 is low, making it easier to cut compared to cutting from the ceramic layer 132. On the other hand, after cutting, the ceramic layer 132 will be completely removed, leaving no ceramic residue, which facilitates subsequent polishing operations. In addition, cutting within a uniform material helps to achieve uniform force, enabling the tool 200 to cut along a straight line as much as possible.

[0069] It should be noted that the step of obtaining the first ratio can be performed before, simultaneously with, or after obtaining the aforementioned location information.

[0070] Based on the above embodiments, in some specific embodiments, the first set value is 0.8, that is, the first conductive layer 131 needs to be thicker than the tool 200. The purpose of this setting is that the first conductive layer 131 is located adjacent to the chip 120, and there is only a very thin welding layer or sintering layer between the first conductive layer 131 and the chip 120. Even if the tool 200 cuts in a homogeneous material, it may still deviate slightly due to its own vibration and other factors. If the thickness of the tool 200 and the first conductive layer 131 are equal or too close, the tool 200 is prone to damaging the chip 120 when it deviates. In this embodiment, by setting the first ratio to be less than or equal to 0.8, the tool 200 has a certain offset margin, reducing the probability of damage to the chip 120.

[0071] Based on the above embodiments, in some specific embodiments, the unpacking method of the power module further includes the following step: a first cutting step is performed by a tool 200 within the first conductive layer 131 and from the side closer to the ceramic layer 132, so that the tool 200 has a larger offset margin. It should be noted that the "side closer to the ceramic layer 132" refers to the centerline of the tool 200 being located between the centerline of the first conductive layer 131 and the ceramic layer 132. It is understood that, while ensuring that the tool 200 can cut within the first conductive layer 131, the closer the tool 200 is to the ceramic layer 132, the less likely it is to damage the chip 120.

[0072] In some embodiments, the unpacking method for the power module further includes the following steps:

[0073] Reference Figure 4Before step two, a second ratio between the thickness of the cutting tool 200 and the thickness of the ceramic layer 132 is obtained. When the first ratio is greater than a first set value and the second ratio is less than or equal to the second set value, the cutting tool 200 performs a first cutting step within the ceramic layer 132. In other words, when the thickness of the first conductive layer 131 is insufficient, but the ceramic layer 132 has sufficient thickness relative to the cutting tool 200, cutting is preferentially performed within the ceramic layer 132. This allows the cutting tool 200 to cut within a uniform material, thus helping to achieve uniform force distribution and enabling the cutting tool 200 to cut as straight as possible. It should be noted that some ceramic layer 132 may remain after cutting using this embodiment. The remaining ceramic layer 132 is removed through subsequent grinding operations. By controlling the cutting position of the cutting tool 200, the amount of residual ceramic layer 132 can be minimized, thereby reducing the subsequent grinding time.

[0074] It should be noted that the step of obtaining the second ratio can be performed before, simultaneously with, or after obtaining the aforementioned location information.

[0075] Based on the above embodiments, in some specific embodiments, the second setting value is 1, that is, the thickness of the tool 200 can be equal to the thickness of the ceramic layer 132 at most, in which case there is basically no residue in the ceramic layer 132. Unlike cutting the first conductive layer 131, there is a first conductive layer 131 between the ceramic layer 132 and the chip 120. Even if the tool 200 deviates slightly due to factors such as vibration, it will only cut into the first conductive layer 131 and will hardly reach the chip 120. Therefore, the thickness of the tool 200 and the ceramic layer 132 can be set to be equal. It is understood that in order to ensure that the tool 200 has a certain offset margin, thereby ensuring that the tool 200 always cuts within the ceramic layer 132, the thickness of the tool 200 is usually less than the thickness of the ceramic layer 132.

[0076] Based on the above embodiments, in some specific embodiments, the unpacking method of the power module further includes the following step: a first cutting step is performed by a tool 200 within the ceramic layer 132 and from the side closest to the first conductive layer 131, so that the tool 200 has a larger offset margin. It should be noted that the "side closest to the first conductive layer 131" refers to the centerline of the tool 200 being located between the centerline of the ceramic layer 132 and the first conductive layer 131. It is understood that, while ensuring that the tool 200 can cut within the ceramic layer 132, the closer the tool 200 is to the first conductive layer 131, the less ceramic layer 132 remains.

[0077] In some embodiments, the unpacking method for the power module further includes the following steps:

[0078] Reference Figure 5When the first ratio is greater than the first set value and the second ratio is greater than the second set value, the tool 200 performs a first cutting step at the junction of the first conductive layer 131 and the ceramic layer 132. In other words, when the thickness of both the first conductive layer 131 and the ceramic layer 132 is insufficient, cutting is performed at the junction of the first conductive layer 131 and the ceramic layer 132. After cutting, the ceramic layer 132 will be completely removed without any ceramic residue, facilitating subsequent polishing operations. It should be noted that since the tool 200 in this embodiment needs to cut both the first conductive layer 131 and the ceramic layer 132 simultaneously, there is an uneven force distribution compared to cutting entirely within the first conductive layer 131 or entirely within the ceramic layer 132. Therefore, its offset will be greater than the previous two cases, and there is also a possibility of jamming. However, even so, compared with the conventional polishing and opening method, this embodiment can still reduce costs and improve efficiency.

[0079] In some embodiments, the present invention also provides a specific scheme for obtaining location information, referring to... Figure 6 The unpacking method for the power module also includes the following steps:

[0080] The power module is cut in a second cutting step along the first direction or in the opposite direction. For example, it is cut from the front side 111 of the mold 110 to the back side 112, or from the back side 112 of the mold 110 to the front side 111, to form a cross-section that exposes the first conductive layer 131, the ceramic layer 132, and the second conductive layer 133.

[0081] Once the first conductive layer 131, the ceramic layer 132, and the second conductive layer 133 are exposed through the cut surface, the position information of the first conductive layer 131 and / or the ceramic layer 132 in the first direction can be obtained through the cut surface.

[0082] It should be noted that the second cutting step in this embodiment can also be performed by the cutter 200. In addition, in order to facilitate the subsequent first cutting step, the cutting surface is parallel to the long side or short side of the power module 100.

[0083] Based on the above embodiments, in some specific embodiments, the unpacking method of the power module further includes the following steps:

[0084] A perspective image of the power module is obtained from one side of the front 111 or the back 112 of the mold body 110, with reference to... Figure 6 The perspective image can show the outline of the chip 120 and the outline of the heat sink 130, wherein the outline of the chip 120 is marked by a dashed line and the outline of the heat sink 130 is marked by a dotted line.

[0085] The cutting position for the second cutting step is selected based on the aforementioned perspective image, so that the cutting position avoids the chip 120 and passes through the heat dissipation substrate 130. In this way, the first conductive layer 131, ceramic layer 132, and second conductive layer 133 can be exposed on the cut surface without damaging the chip 120 and the leads electrically connected to the chip 120.

[0086] It should be noted that the fluoroscopic image can be obtained by taking an X-ray of the power module.

[0087] In some embodiments, the power module is secured by mounting component 300, see reference 300. Figure 7 The mounting component 300 is made of a rigid structure, such as metal, and has a mounting surface 310 on one side for attaching the power module. At least one of the mounting surface 310 and the front surface 111 of the molded body 110 has a recess that can be filled with adhesive 400 to increase the connection strength between the mounting component 300 and the molded body 110. In some embodiments, only the mounting surface 310 has a recess; in other embodiments, only the front surface 111 of the molded body 110 has a recess; and in still other embodiments... Figure 7 As shown in the example, both the mounting surface 310 and the front surface 111 of the molded body 110 are provided with recesses to further increase the connection strength. For ease of description, the recess on the front surface 111 of the molded body 110 is named the first recess 113, and the recess on the mounting surface 310 is named the second recess 320. The first recess 113 and the second recess 320 can have the same or different shapes, and they can be aligned or staggered. The first recess 113 can be formed by laser ablation or other methods.

[0088] It should be noted that the present invention does not limit the shape of the recessed portion; it can be a continuously distributed groove or an intermittently distributed pit, etc. Figure 7 Taking the first recessed portion 113 as an example, it includes multiple interconnected transverse grooves and longitudinal grooves.

[0089] Based on the above structure, the back-side opening method of this embodiment further includes a step of fixing the power module with the mounting component 300 for lateral cutting, as described above. Figure 7 Specifically, it includes the following steps:

[0090] Install component 300;

[0091] An adhesive 400 is provided between the mounting surface 310 and the front surface 111 of the mold body 110, so that the power module 100 and the mounting component 300 are pressed together. The adhesive 400 is heated and melted, and then filled into the aforementioned recessed portion under pressure.

[0092] Cool the adhesive 400 to bond the power module to the mounting component 300.

[0093] It should be noted that, in order to achieve the effect of mutual abutment between the power module 100 and the mounting component 300, the mounting component 300 can be fixed and then pressure can be applied to the power module 100, or the power module 100 can be fixed and then pressure can be applied to the mounting component 300, or pressure can be applied to both the power module 100 and the mounting component 300 at the same time. For example, the power module 100 and the mounting component 300 can be placed between the clamps and clamped.

[0094] It should also be noted that when heating the adhesive 400, the mounting component 300 can be heated first, and the adhesive 400 can be heated by the heated mounting component 300. The adhesive 400 used in this embodiment can be paraffin wax, which has a certain fluidity after melting and can be uniformly filled between the power module 100 and the mounting component 300 under pressure.

[0095] It should also be noted that after the mounting component 300 is bonded to the power module 100, the mounting component 300 can be clamped by an external clamp to keep the mounting component 300 and the power module 100 fixed for easy subsequent cutting. In addition, the mounting component 300 can also be provided with connection structures such as threaded holes and fixed to the external structure by threaded fasteners.

[0096] In this embodiment, the power module 100 is fixed by adhesive bonding using the mounting component 300. No additional connection structure is required between the mounting component 300 and the power module 100. Furthermore, the mounting component 300 is fixed using clamps or threaded fasteners, eliminating the need for direct fixation of the power module 100. Therefore, the circumferential surface of the power module 100 is unobstructed, facilitating the first cutting operation from the side. Additionally, this embodiment provides a recess in at least one of the mounting surface 310 and the front surface 111 of the molded body 110. The adhesive 400 filling the recess, after curing, forms a limiting structure, increasing the connection strength between the mounting component 300 and the molded body 110 and preventing relative displacement between them during the cutting process.

[0097] In some embodiments, when the first cutting step is performed by the tool 200, the thickness of the tool 200 is 0.3 mm to 0.5 mm, thereby adapting to the cutting of a thinner heat dissipation substrate 130. It should be noted that the tool 200 can be made thicker within an allowable range, thereby increasing the strength of the tool 200, reducing the vibration of the tool 200 during cutting, and also forming a larger opening to facilitate chip removal.

[0098] In some embodiments, when the first cutting step is performed by the tool 200, the feed rate of the tool 200 is 1 mm / min to 2 mm / min. Using a relatively slow feed rate allows for more thorough cutting and helps the tool 200 to cut along a straight line.

[0099] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A method for opening a power module, characterized in that, The invention is applied to a power module, which includes a molded body, a chip, and a heat dissipation substrate. The chip is located within the molded body, and the molded body has a first surface and a second surface disposed opposite to each other. The chip and the heat dissipation substrate are stacked along a first direction from the first surface to the second surface. The heat dissipation substrate includes a first conductive layer, a ceramic layer, and a second conductive layer stacked along the first direction. The first conductive layer and the ceramic layer are located within the molded body, and the second conductive layer is partially located within the molded body, with the surface of the second conductive layer facing away from the ceramic layer exposed from the second surface. The method for opening the power module includes the following steps: Obtain the position information of the first conductive layer and / or the ceramic layer in the first direction; Based on the location information, a first cutting step is performed by a tool from the side of the mold body along a second direction perpendicular to the first direction to remove the second conductive layer and at least a portion of the ceramic layer; The cut power module is polished to expose the chip; The unpacking method for the power module further includes the following steps: A first ratio is obtained between the thickness of the cutting tool and the thickness of the first conductive layer. When the first ratio is less than or equal to a first set value, the cutting tool cuts within the range of the first conductive layer to remove the second conductive layer and all of the ceramic layer.

2. The method for opening the power module according to claim 1, characterized in that, The first setting value is 0.

8.

3. The method for opening the power module according to claim 1, characterized in that, The method for opening the power module further includes the following steps: A second ratio is obtained between the thickness of the cutting tool and the thickness of the ceramic layer. When the first ratio is greater than the first set value and the second ratio is less than or equal to the second set value, the first cutting step is performed by the cutting tool within the range of the ceramic layer to remove the second conductive layer and at least a portion of the ceramic layer.

4. The method for opening the power module according to claim 3, characterized in that, The second setting value is 1.

5. The method for opening the power module according to claim 3, characterized in that, The method for opening the power module further includes the following steps: When the first ratio is greater than the first set value and the second ratio is greater than the second set value, the first cutting step is performed at the junction of the first conductive layer and the ceramic layer by the cutting tool to remove the second conductive layer and all of the ceramic layer.

6. The method for opening the power module according to claim 1, characterized in that, The method for opening the power module further includes the following steps: A second cutting step is performed on the power module along the first direction or in a direction opposite to the first direction to form a cross-section that exposes the first conductive layer, the ceramic layer and the second conductive layer; The positional information of the first conductive layer and / or the ceramic layer in the first direction is obtained through the cross-section.

7. The method for opening the power module according to claim 6, characterized in that, The method for opening the power module further includes the following steps: A perspective image of the power module is obtained from one side of the first surface or the second surface. Based on the perspective image, a cutting position for the second cutting step is selected so that the cutting position avoids the chip and passes through the heat dissipation substrate.

8. The method for opening the power module according to claim 1, characterized in that, The method for opening the power module further includes the following steps: A mounting component is provided, the mounting component having a mounting surface, the mounting surface and / or the first surface having a recess; An adhesive is applied between the mounting surface and the first surface to press the power module against the mounting component, and the adhesive is heated to fill the recessed portion. The adhesive is cooled to bond the power module to the mounting component.

9. The method for opening the power module according to claim 1, characterized in that, The first cutting step is performed by a tool along the second direction from the side of the molded body, wherein the unpacking method of the power module includes at least one of the following parameters: The thickness of the cutting tool is 0.3 mm to 0.5 mm; The feed rate of the tool is 1 mm / min to 2 mm / min.

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