Metallic preform, semiconductor device and packaging method

Abstract

The application relates to a metal prefabricated sheet, a semiconductor device and a packaging method. The metal prefabricated sheet is characterized in that a first sintering layer is arranged on a first surface of a metal layer; a second sintering layer is arranged on a second surface of the metal layer; a thermal decomposition bonding glue is arranged on at least the first sintering layer or the second sintering layer, the thermal decomposition bonding glue is used for pre-fixing the first sintering layer on a chip to be mounted or pre-fixing the second sintering layer on a substrate; the thermal decomposition bonding glue is volatilized and decomposed when sintering reaches a first preset temperature, the first sintering layer is connected to the chip to be mounted or the second sintering layer is connected to the substrate, precise and firm temporary fixing of the metal prefabricated sheet on the chip or the substrate is realized, the chip is prevented from falling off or deviating on the substrate before sintering, the thermal decomposition bonding glue is completely and residue-free discharged in the sintering process, a clean and high-strength sintering interconnection interface is finally obtained, the thermal decomposition bonding glue is prevented from causing pollution to the chip, and the reliability of sintering of the metal prefabricated sheet is improved.

Description

Technical Field

[0001] This application relates to the field of semiconductor packaging technology, and in particular to a metal preform, a semiconductor device, and a packaging method. Background Technology

[0002] Metal preforms are sintered metal preforms used for chip sintering interconnection, forming pre-interconnections between the chip and the substrate pads. When using metal preforms for chip mounting, especially in complex processes involving large chips or multiple chips to be mounted simultaneously, the metal preforms need to be precisely and stably temporarily fixed to the pads of the chip or substrate before entering the sintering furnace.

[0003] In existing technologies, metal preforms are typically temporarily fixed to the pads of chips or substrates by dispensing or coating adhesive. However, the adhesive carbonizes at high sintering temperatures, and residual carbides exist at the sintering interface, forming insulating layers and stress concentration points. This severely degrades the thermal conductivity, electrical conductivity, and connection reliability of the interconnect layers, leading to premature failure of semiconductor chips. Summary of the Invention

[0004] Based on this, a metal preform, a semiconductor device, and a packaging method are provided.

[0005] In a first aspect, this application provides a metal preform, comprising:

[0006] A metal layer having a first and a second surface opposite to each other;

[0007] The first sintered layer is disposed on the first surface of the metal layer;

[0008] The second sintered layer is disposed on the second side of the metal layer;

[0009] The thermally decomposable bonding adhesive is disposed at least on the first sintered layer or the second sintered layer. The thermally decomposable bonding adhesive is used to pre-fix the first sintered layer to the chip to be mounted or to pre-connect the second sintered layer to the substrate. The thermally decomposable bonding adhesive is also used to volatilize and decompose when sintering reaches a first preset temperature, so that the first sintered layer is connected to the chip to be mounted or the second sintered layer is connected to the substrate.

[0010] In one embodiment, the thermally decomposable bonding adhesive includes a first thermally decomposable bonding adhesive and a second thermally decomposable bonding adhesive; the first sintered layer is provided with at least two first coating areas, and the second sintered layer is provided with at least two second coating areas;

[0011] Each first coating area is provided with a first thermally decomposable bonding adhesive, and each second coating area is provided with a second thermally decomposable bonding adhesive.

[0012] In one embodiment, the first coating area is disposed adjacent to the side of the first sintered layer, and the distance between the first coating area and the corresponding adjacent side of the first sintered layer is between 0.1 mm and 1 mm.

[0013] The second coating area is disposed adjacent to the side of the second sintered layer, and the distance between the second coating area and the corresponding adjacent side of the second sintered layer is between 0.1 mm and 1 mm.

[0014] In one embodiment, the first thermally decomposable bonding adhesive is a thermoplastic polymer or a thermoplastic oligomer;

[0015] The second thermally decomposed bonded adhesive is a thermoplastic polymer or thermoplastic oligomer.

[0016] In one embodiment, the metal layer includes a first metal plating layer, a second metal plating layer, and a metal sheet;

[0017] The metal sheet has a first side and a second side, a first metal plating layer is disposed on the first side of the metal sheet, and a second metal plating layer is disposed on the second side of the metal sheet;

[0018] The first sintered layer is disposed on the first metal plating layer, and the second sintered layer is disposed on the second metal plating layer.

[0019] In one embodiment, the first sintered layer includes silver particles with a first diameter of 50 nm to 5 μm, and the thickness of the first sintered layer is between 20 μm and 100 μm.

[0020] The second sintered layer includes silver particles with a second diameter of 50 nm to 5 μm, and the thickness of the second sintered layer is between 20 μm and 100 μm.

[0021] Secondly, this application also provides a semiconductor device, including a chip to be mounted, a substrate, and a metal preform as described above; the metal preform at least pre-fixes the chip to be mounted or the substrate so that when sintering reaches a first preset temperature, the metal preform connects the chip to be mounted and the substrate.

[0022] In one embodiment, the chip to be mounted is a SiC module or an IGBT module.

[0023] Thirdly, this application also provides a packaging method for a semiconductor device, applied to the semiconductor device as described above, the packaging method comprising:

[0024] The metal preform is placed on the substrate;

[0025] The chip to be mounted is placed on the metal preform to form the first semi-finished product;

[0026] Based on the second preset temperature, the first semi-finished product is heated to solidify the thermal decomposition bonding adhesive of the metal preform, so that the metal preform is at least pre-fixed to the chip or substrate to be mounted, in order to form the second semi-finished product.

[0027] Based on the third preset temperature, the second semi-finished product is sintered to volatilize and decompose the thermal decomposition bonding adhesive of the metal preform, so that the metal preform connects the chip to be mounted and the substrate to obtain a semiconductor device.

[0028] In one embodiment, the thermally decomposable bonding adhesive of the metal preform is cured based on a second preset temperature, so that the metal preform is at least pre-fixed to the chip or substrate to be mounted, to form a second semi-finished product, including:

[0029] Based on a preset duration, preset pressure, and a second preset temperature, pressure is applied to the first semi-finished product to cure the thermal decomposition bonding adhesive of the metal preform and to pre-fix the metal preform at least to the chip or substrate to be mounted, so as to form the second semi-finished product.

[0030] One of the above technical solutions has the following advantages and beneficial effects:

[0031] In the aforementioned metal preform, the metal layer has a first side and a second side; a first sintered layer is disposed on the first side of the metal layer; a second sintered layer is disposed on the second side of the metal layer; a thermally decomposable bonding adhesive is disposed on at least the first sintered layer or the second sintered layer, the thermally decomposable bonding adhesive is used to pre-fix the first sintered layer to the chip to be mounted or to pre-fix the second sintered layer to the substrate; the thermally decomposable bonding adhesive is also used to volatilize and decompose when sintering reaches a first preset temperature, so that the first sintered layer is connected to the chip to be mounted or the second sintered layer is connected to the substrate, thereby achieving precise and firm temporary fixation of the metal preform on the chip or substrate, and ensuring that the thermally decomposable bonding adhesive is completely and without residue discharged during the sintering process, ultimately obtaining a clean and high-strength sintered interconnect interface. This application, by applying thermally decomposable bonding adhesive at least on the first sintering layer or the second sintering layer, enables pre-fixation of the first sintering layer to the chip to be mounted or pre-fixation of the second sintering layer to the substrate. This allows for precise and stable temporary fixation of the metal preform to the chip or substrate before entering the sintering furnace, preventing the chip from easily detaching or shifting from the substrate before sintering. During sintering, the thermally decomposable bonding adhesive undergoes volatilization and decomposition without any inorganic residue, preventing contamination of the chip. This achieves reliable pre-interconnection and ensures that the interconnection interface is completely free of contamination after sintering, improving the reliability of metal preform sintering. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the first structure of the metal preform in the embodiments of this application;

[0033] Figure 2This is a schematic diagram of the second structure of the metal preform in an embodiment of this application;

[0034] Figure 3 This is a schematic diagram of the structure of the semiconductor device in the embodiments of this application;

[0035] Figure 4 This is a schematic flowchart of the semiconductor device packaging method in the embodiments of this application.

[0036] Figure label:

[0037] 110. Metal layer; 112. First metal plating layer; 114. Second metal plating layer; 116. Metal sheet; 120. First sintered layer; 130. Second sintered layer; 140. Thermally decomposable bonding adhesive; 142. First thermally decomposable bonding adhesive; 144. Second thermally decomposable bonding adhesive; 20. Chip to be mounted; 30. Substrate. Detailed Implementation

[0038] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0039] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0040] In addition, the term "multiple" should mean two or more.

[0041] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0042] In one embodiment, such as Figure 1As shown, a metal preform is provided, including a metal layer 110, a first sintered layer 120, a second sintered layer 130, and a thermally degradable bonding adhesive 140. The metal layer 110 has a first side and a second side facing each other. The first sintered layer 120 is disposed on the first side of the metal layer 110. The second sintered layer 130 is disposed on the second side of the metal layer 110. The thermally degradable bonding adhesive 140 is disposed on at least the first sintered layer 120 or the second sintered layer 130. The thermally degradable bonding adhesive 140 is used to pre-fix the first sintered layer 120 to the chip 20 to be mounted or to pre-fix the second sintered layer 130 to the substrate 30. The thermally degradable bonding adhesive 140 is also used to volatilize and decompose when sintering reaches a first preset temperature, so that the first sintered layer 120 is connected to the chip 20 to be mounted or the second sintered layer 130 is connected to the substrate 30.

[0043] In this application, the metal preform is used in semiconductor devices to connect the chip 20 to be mounted onto the substrate 30. The chip 20 to be mounted may be, but is not limited to, a SiC module or an IGBT module package. The substrate 30 is provided with pads, one side of the metal preform is connected to the pads of the substrate 30, and the other side of the metal preform is connected to the chip 20 to be mounted.

[0044] The metal layer 110 has a sheet-like structure and can be a single-layer metal layer or a composite metal layer. The shape of the metal layer 110 can be, but is not limited to, square. It should be noted that the specific shape of the metal layer 110 can be determined according to the specific shapes of the chip 20 to be mounted and the substrate 30. For example, the metal layer 110 can be a square sheet-like structure. The metal layer 110 has corresponding first and second surfaces. The first surface of the metal layer 110 is used to form the first sintered layer 120, and the second surface of the metal layer 110 is used to form the second sintered layer 130.

[0045] The first sintered layer 120 can completely cover the metal layer 110, and the shape of the first sintered layer 120 is determined according to the shape of the metal layer 110. The first sintered layer 120 can be a sintered silver layer, and the first sintered layer 120 is provided with a preset amount of silver particles. The first sintered layer 120 is coated on the first surface of the metal layer 110. During sintering, the first sintered layer 120 solidifies to firmly connect the chip 20 to be mounted to the first surface of the metal layer 110 through the first sintered layer 120, so that the chip 20 to be mounted and the metal layer 110 are electrically connected.

[0046] The second sintered layer 130 can completely cover the metal layer 110, and the shape of the second sintered layer 130 is determined according to the shape of the metal layer 110. The second sintered layer 130 can be a sintered silver layer, and the second sintered layer 130 is provided with a predetermined amount of silver particles. The second sintered layer 130 is coated on the second side of the metal layer 110. During sintering, the second sintered layer 130 solidifies to firmly connect the pads of the substrate 30 to the second side of the metal layer 110 through the first sintered layer 120, so that the substrate 30 and the metal layer 110 are electrically connected.

[0047] The thermally decomposable bonding adhesive 140 refers to an adhesive that has an adhesive and fixing function and can completely volatilize and decompose at a first preset temperature, leaving no inorganic residue. The thermally decomposable bonding adhesive 140 can be used to bond the chip 20 to be mounted to the first sintered layer 120, so as to pre-fix the chip 20 to be mounted to the first sintered layer 120; the thermally decomposable bonding adhesive 140 can also be used to bond the substrate 30 to the second sintered layer 130, so as to pre-fix the substrate 30 to the first sintered layer 120.

[0048] For example, thermally decomposable bonding adhesive 140 is applied to a preset position on the first sintering layer 120. The chip 20 to be mounted is picked up by a pick-up device (such as a pick-and-place machine) and precisely aligned onto the first sintering layer 120. Through the adhesive effect of the thermally decomposable bonding adhesive 140, the chip 20 to be mounted is pre-fixed on the first sintering layer 120, thereby preventing the chip 20 to be mounted from falling off or shifting before sintering, and achieving precise and firm temporary fixation of the metal preform on the chip. When the pre-fixed chip 20 to be mounted is sintered, the heating temperature of the thermal decomposition bonding adhesive 140 gradually increases. When the heating temperature of the thermal decomposition bonding adhesive 140 reaches the first preset temperature, the thermal decomposition bonding adhesive 140 undergoes volatilization and decomposition. All the molecular chains of the thermal decomposition bonding adhesive 140 will escape in gaseous form, leaving no residue (such as carbon residue). This ensures that the thermal decomposition bonding adhesive 140 is completely and residue-free discharged during the sintering process, ultimately obtaining a clean and high-strength sintered interconnect interface between the chip and the metal preform.

[0049] For example, thermal decomposition bonding adhesive 140 is applied to a preset position on the second sintering layer 130, and a metal preform is picked up by a pick-up device (such as a pick-and-place machine) and precisely aligned onto the pads of the substrate 30. Through the adhesive effect of the thermal decomposition bonding adhesive 140, the substrate 30 is pre-fixed to the second sintering layer 130, thereby preventing the substrate 30 from falling off or shifting from the metal preform before sintering, and achieving precise and firm temporary fixation of the metal preform on the substrate 30. When the pre-fixed substrate 30 is sintered, the heating temperature of the thermal decomposition bonding adhesive 140 gradually increases. When the heating temperature of the thermal decomposition bonding adhesive 140 reaches the first preset temperature, the thermal decomposition bonding adhesive 140 undergoes volatilization and decomposition. All the molecular chains of the thermal decomposition bonding adhesive 140 will escape in gaseous form without leaving any residue (such as carbon residue). This ensures that the thermal decomposition bonding adhesive 140 is completely and residue-free discharged during the sintering process, ultimately obtaining a clean and high-strength sintered interconnection interface between the substrate 30 and the metal preform.

[0050] It should be noted that metal preforms mainly refer to connectors used in semiconductor assembly or packaging processes. In some embodiments, metal preforms are conductive sintering films or conductive sintering sheets used in chip sintering, such as DTS (Direct Thermal Sintering), sintered silver preforms, etc. In chip sintering scenarios, the size of metal preforms is very small, so conventional products are prone to chip detachment or displacement from the substrate 30 before entering the sintering furnace or during sintering, making it difficult to accurately and stably fix them temporarily to the chip or substrate 30. Currently, traditional adhesives are usually used to pre-fix the chip or substrate 30 by dispensing or coating adhesive. However, traditional adhesives carbonize at the high temperature of sintering, and residual carbides exist at the sintering interface, forming an insulating layer and stress concentration points, which seriously degrades the thermal conductivity, electrical conductivity, and connection reliability of the interconnect layer, leading to early device failure. This application improves the structure of the metal preform and selects and coordinates the materials and processes to achieve precise and firm temporary fixation of the metal preform on the chip, and ensures that the adhesive is completely and without residue discharged during the sintering process, ultimately obtaining a clean and high-strength sintered interconnect interface.

[0051] In the above embodiments, the metal layer 110 has a first side and a second side facing each other; the first sintered layer 120 is disposed on the first side of the metal layer 110; the second sintered layer 130 is disposed on the second side of the metal layer 110; the thermally decomposable bonding adhesive 140 is disposed on at least the first sintered layer 120 or the second sintered layer 130, and the thermally decomposable bonding adhesive 140 is used to pre-fix the first sintered layer 120 to the chip 20 to be mounted or to pre-fix the second sintered layer 130 to the substrate 30; the thermally decomposable bonding adhesive 140 is also used to volatilize and decompose when the sintering reaches a first preset temperature, so that the first sintered layer 120 is connected to the chip 20 to be mounted or the second sintered layer 130 is connected to the substrate 30, thereby achieving precise and firm temporary fixation of the metal preform on the chip or substrate 30, and ensuring that the thermally decomposable bonding adhesive 140 is completely and without residue discharged during the sintering process, ultimately obtaining a clean and high-strength sintered interconnect interface. This application, by disposing of thermally decomposable bonding adhesive 140 on at least the first sintering layer 120 or the second sintering layer 130, can pre-fix the first sintering layer 120 to the chip 20 to be mounted or pre-fix the second sintering layer 130 to the substrate 30. This allows for precise and stable temporary fixation of the metal preform to the chip or substrate 30 before entering the sintering furnace, preventing the chip from easily falling off or shifting on the substrate 30 before sintering. During sintering, the thermally decomposable bonding adhesive 140 can volatilize and decompose without any inorganic residue, preventing the thermally decomposable bonding adhesive 140 from contaminating the chip. This achieves reliable pre-interconnection and ensures that the interconnection interface is completely uncontaminated after sintering, improving the reliability of metal preform sintering.

[0052] In one embodiment, such as Figure 2 As shown, the thermally decomposable bonding adhesive 140 includes a first thermally decomposable bonding adhesive 142 and a second thermally decomposable bonding adhesive 144; the first sintered layer 120 is provided with at least two first coating areas, and the second sintered layer 130 is provided with at least two second coating areas; each first coating area is provided with the first thermally decomposable bonding adhesive 142, and each second coating area is provided with the second thermally decomposable bonding adhesive 144.

[0053] Both the first thermally decomposable bonding adhesive 142 and the second thermally decomposable bonding adhesive 144 have an adhesive and fixing function, and can completely volatilize and decompose at the first preset temperature without any inorganic residue.

[0054] The first coating area is disposed on the outer surface of the first sintered layer 120, and the inner surface of the first sintered layer 120 is bonded to the first surface of the metal layer 110. The first coating area is used to coat the first pyrolytic bonding adhesive 142, so that the first pyrolytic bonding adhesive 142 is pre-installed on the first sintered layer 120. The first coating area can be a regular shape such as circular or square; in another example, the first coating area can also be an irregular shape. In some examples, the outer surface of the first sintered layer 120 may be provided with two first coating areas, which are arranged diagonally; in other examples, the outer surface of the first sintered layer 120 may be provided with four first coating areas, which are arranged near the corresponding corners of the first sintered layer 120. If the first sintered layer 120 has a square structure, the four first coating areas are arranged near the corresponding included angles of the first sintered layer 120.

[0055] The second coating area is disposed on the outer surface of the second sintered layer 130, and the inner surface of the second sintered layer 130 is bonded to the second surface of the metal layer 110. The second coating area is used to coat the second pyrolytic bonding adhesive 144, so that the second pyrolytic bonding adhesive 144 is pre-installed on the second sintered layer 130. The second coating area can be a regular shape such as circular or square; in another example, the second coating area can also be an irregular shape. In some examples, the outer surface of the second sintered layer 130 may be provided with two second coating areas, which are arranged diagonally; in other examples, the outer surface of the second sintered layer 130 may be provided with four second coating areas, which are arranged near the corresponding corners of the second sintered layer 130. If the second sintered layer 130 has a square structure, the four second coating areas are arranged near the corresponding included angles of the second sintered layer 130.

[0056] For example, a first thermally decomposable bonding adhesive 142 is applied to the corresponding first coating area of ​​the first sintered layer 120, and a second thermally decomposable bonding adhesive 144 is applied to the corresponding second coating area of ​​the second sintered layer 130. A metal preform is picked up using a pick-up device (such as a pick-and-place machine). The second sintered layer 130 of the metal preform is precisely aligned onto the pads of the substrate 30. Through the adhesive effect of the second thermally decomposable bonding adhesive 144, the second sintered layer 130 of the metal preform is pre-fixed onto the substrate 30. Next, the chip 20 to be mounted is picked up using a pick-up device and precisely aligned onto the first sintered layer 120. Through the adhesive effect of the first thermally decomposable bonding adhesive 142, the chip 20 to be mounted is pre-fixed onto the first sintered layer 120. This can prevent the chip 20 to be mounted and the substrate 30 from falling off or shifting before or during sintering, thus achieving precise and firm temporary fixation of the metal preform on the chip and the substrate 30. When the pre-fixed chip 20 and substrate 30 are sintered, the heating temperature of the first thermally decomposable bonding adhesive 142 and the second thermally decomposable bonding adhesive 144 gradually increases. When the heating temperature of the first thermally decomposable bonding adhesive 142 and the second thermally decomposable bonding adhesive 144 reaches the first preset temperature, the first thermally decomposable bonding adhesive 142 and the second thermally decomposable bonding adhesive 144 undergo volatilization and decomposition. The molecular chains of the first thermally decomposable bonding adhesive 142 and the second thermally decomposable bonding adhesive 144 will all escape in gaseous form, leaving no residue (such as carbon residue). This ensures that the first thermally decomposable bonding adhesive 142 and the second thermally decomposable bonding adhesive 144 are completely and residue-free discharged during the sintering process, ultimately obtaining a clean and high-strength sintered interconnection interface between the chip and the metal preform, as well as a sintered interconnection interface between the substrate 30 and the metal preform.

[0057] It should be noted that the first preset temperature is lower than the highest temperature during the sintering process. The first preset temperature can be set to 150°C to 220°C, and the specific value of the first preset temperature is determined according to the specific materials of the first thermally decomposable bonding adhesive 142 and the second thermally decomposable bonding adhesive 144. When the heating temperature of the first thermally decomposable bonding adhesive 142 and the second thermally decomposable bonding adhesive 144 reaches the first preset temperature, they can quickly depolymerize or vaporize, achieving complete volatilization and decomposition, thus avoiding the generation of residues after sintering that could affect the thermal conductivity, electrical conductivity, and connection reliability of the chip.

[0058] In one embodiment, the first coating area is disposed adjacent to the side of the first sintered layer 120, and the distance between the first coating area and the corresponding adjacent side of the first sintered layer 120 is between 0.1 mm and 1 mm; the second coating area is disposed adjacent to the side of the second sintered layer 130, and the distance between the second coating area and the corresponding adjacent side of the second sintered layer 130 is between 0.1 mm and 1 mm.

[0059] For example, the first sintered layer 120 has a square structure and four included corners. The first coating area is positioned near the two sides of the corresponding included corners. The distance between the first coating area and the corresponding adjacent side of the first sintered layer 120 is between 0.1 mm and 1 mm, allowing the first coating area to be positioned close to the corresponding included corner of the first sintered layer 120. Using a precision dispensing device, the first thermally decomposable bonding adhesive 142 is applied to each of the first coating areas of the first sintered layer 120. By placing the chip 20 to be mounted on the first sintered layer 120, the first thermally decomposable bonding adhesive 142 on the first sintered layer 120 can be bonded to the chip 20 to be mounted, thus pre-fixing the first sintered layer 120 and the chip 20 to be mounted, achieving precise and firm temporary fixation between the metal preform and the chip 20 to be mounted.

[0060] The second sintered layer 130 has a square structure with four included corners. The second coating area is positioned near the two sides of the corresponding included corners. The distance between the second coating area and the corresponding adjacent side of the second sintered layer 130 is between 0.1 mm and 1 mm, allowing the second coating area to be positioned close to the corresponding included corner of the second sintered layer 130. Using a precision dispensing device, the second pyrolytic bonding adhesive 144 is applied to each of the second coating areas of the second sintered layer 130. By placing the substrate 30 on the second sintered layer 130, each of the second pyrolytic bonding adhesives 144 on the second sintered layer 130 can be bonded to the substrate 30, pre-fixing the second sintered layer 130 and the substrate 30, and achieving precise and firm temporary fixation of the metal preform and the substrate 30.

[0061] In one embodiment, the first thermally decomposable bonding adhesive 142 is a thermoplastic polymer or a thermoplastic oligomer; the second thermally decomposable bonding adhesive 144 is a thermoplastic polymer or a thermoplastic oligomer.

[0062] For example, the first thermally decomposable bonding adhesive 142 can be, but is not limited to, polystyrene, polycarbonate, or a specific type of polymethyl methacrylate. The second thermally decomposable bonding adhesive 144 can be, but is not limited to, polystyrene, polycarbonate, or a specific type of polymethyl methacrylate. Based on the low-temperature bonding and fixing effect of the first thermally decomposable bonding adhesive 142 and the second thermally decomposable bonding adhesive 144, reliable pre-interconnection can be achieved, and the interconnection interface can be ensured to be completely free of contamination after sintering, thereby improving the reliability of metal preform sintering.

[0063] In one embodiment, such as Figure 2 and Figure 3As shown, the metal layer 110 includes a first metal plating layer 112, a second metal plating layer 114, and a metal sheet 116; the metal sheet 116 has a first surface and a second surface, the first metal plating layer 112 is disposed on the first surface of the metal sheet 116, and the second metal plating layer 114 is disposed on the second surface of the metal sheet 116; a first sintered layer 120 is disposed on the first metal plating layer 112, and a second sintered layer 130 is disposed on the second metal plating layer 114.

[0064] The metal sheet 116 can be copper foil, and it can be in the form of a square sheet with a thickness between 50 μm and 100 μm. The first metal plating layer 112 can be made of silver, and its thickness can be between 0.1 μm and 2 μm. The second metal plating layer 114 can also be made of silver, and its thickness can be between 0.1 μm and 2 μm. For example, electroplating or electroless silver plating can be used to deposit the first metal plating layer 112 on the first surface of the metal sheet 116; similarly, electroplating or electroless silver plating can be used to deposit the second metal plating layer 114 on the first surface of the metal sheet 116.

[0065] In one example, the first sintered layer 120 includes silver particles with a first diameter of 50 nm to 5 μm and a thickness between 20 μm and 100 μm; the second sintered layer 130 includes silver particles with a second diameter of 50 nm to 5 μm and a thickness between 20 μm and 100 μm. The first sintered layer 120 can be disposed on the first metal plating layer 112 by means of coating, printing, or bonding, and the second sintered layer 130 can be disposed on the second metal plating layer 114 by means of coating, printing, or bonding.

[0066] For example, the preparation process of the metal preform is as follows: a first metal plating layer 112 is disposed on the first surface of the metal sheet 116, and a second metal plating layer 114 is disposed on the second surface of the metal sheet 116; a first sintered layer 120 is disposed on the first metal plating layer 112, and a second sintered layer 130 is disposed on the second metal plating layer 114; a first thermally decomposable bonding adhesive 142 is coated on each first coating area of ​​the first sintered layer 120 using a precision dispensing device, and a second thermally decomposable bonding adhesive 144 is coated on each second coating area of ​​the second sintered layer 130, thereby obtaining the metal preform. The first thermally decomposable bonding adhesive 142 can pre-fix the first sintered layer 120 and the chip 20 to be mounted, and the second thermally decomposable bonding adhesive 144 can pre-fix the second sintered layer 130 and the substrate 30. This allows the metal preform to be precisely and stably temporarily fixed to the chip or substrate 30 before entering the sintering furnace. During sintering, the thermally decomposable bonding adhesive 140 can volatilize and decompose without any inorganic residue, avoiding contamination of the chip by the thermally decomposable bonding adhesive 140. This not only achieves reliable pre-interconnection but also ensures that the interconnect interface is completely free of contamination after sintering, thus improving the reliability of the metal preform sintering.

[0067] In one embodiment, such as Figure 3 As shown, a semiconductor device is also provided, including a chip to be mounted 20, a substrate 30, and a metal preform as described above; the metal preform at least pre-fixes the chip to be mounted 20 or the substrate 30 so that when sintering reaches a first preset temperature, the metal preform connects the chip to be mounted 20 and the substrate 30.

[0068] For details regarding the chip 20 to be mounted, the substrate 30, and the metal preform, please refer to the description in the above embodiments, which will not be repeated here.

[0069] By aligning one side of the metal preform on the pads of the substrate 30, and aligning the chip 20 to be mounted on the other side of the metal preform, a thermally decomposable bonding adhesive 140 based on the metal preform is disposed on at least the first sintered layer 120 or the second sintered layer 130. The thermally decomposable bonding adhesive 140 is used to pre-fix the first sintered layer 120 to the chip 20 to be mounted or the second sintered layer 130 to the substrate 30. The thermally decomposable bonding adhesive 140 is also used to volatilize and decompose when sintering reaches a first preset temperature, so that the first sintered layer 120 is connected to the chip 20 to be mounted or the second sintered layer 130 is connected to the substrate 30. This achieves precise and firm temporary fixation of the metal preform on the chip or the substrate 30, and ensures that the thermally decomposable bonding adhesive 140 is completely and without residue discharged during the sintering process, ultimately obtaining a clean and high-strength sintered interconnect interface. This application provides a thermally decomposable bonding adhesive 140 on a metal preform, with the adhesive 140 being applied at least on the first sintering layer 120 or the second sintering layer 130. This allows for pre-fixation of the first sintering layer 120 to the chip 20 to be mounted, or pre-fixation of the second sintering layer 130 to the substrate 30. This ensures that the metal preform is precisely and stably temporarily fixed to the chip or substrate 30 before entering the sintering furnace, preventing the chip from easily detaching or shifting from the substrate 30 before sintering. During sintering, the thermally decomposable bonding adhesive 140 volatilizes and decomposes without any inorganic residue, preventing contamination of the chip. This achieves reliable pre-interconnection and ensures that the interconnect interface is completely free of contamination after sintering, thus improving the reliability of the semiconductor device.

[0070] In one embodiment, the chip to be mounted 20 is either a SiC (silicon carbide) module to be mounted or an IGBT (Insulated Gate Bipolar Transistor) module to be mounted.

[0071] For example, a first thermally decomposable bonding adhesive 142 is provided in the corresponding first coating area of ​​the first sintered layer 120 of the metal preform, and a second thermally decomposable bonding adhesive 144 is provided in the corresponding second coating area of ​​the second sintered layer 130 of the metal preform. The metal preform is picked up by a pick-up device (such as a pick-and-place machine), and the second sintered layer 130 of the metal preform is precisely aligned on the pads of the substrate 30. Through the bonding effect of the second thermally decomposable bonding adhesive 144, the second sintered layer 130 of the metal preform is pre-fixed to the substrate. Next, the SiC module or IGBT module to be mounted is picked up using a picking device and precisely aligned onto the first sintering layer 120. Through the bonding effect of the first thermal decomposition bonding adhesive 142, the chip 20 to be mounted is pre-fixed on the first sintering layer 120, thereby preventing the chip 20 to be mounted and the substrate 30 from falling off or shifting before or during sintering, and achieving precise and firm temporary fixation of the metal preform on the chip and the substrate 30. When the pre-fixed SiC module or IGBT module to be mounted is sintered, the heating temperature of the first thermally decomposable bonding adhesive 142 and the second thermally decomposable bonding adhesive 144 gradually increases. When the heating temperature of the first thermally decomposable bonding adhesive 142 and the second thermally decomposable bonding adhesive 144 reaches the first preset temperature, the first thermally decomposable bonding adhesive 142 and the second thermally decomposable bonding adhesive 144 undergo volatilization and decomposition, leaving no residue (such as carbon residue). This ensures that the first thermally decomposable bonding adhesive 142 and the second thermally decomposable bonding adhesive 144 are completely and residue-free discharged during the sintering process, ultimately resulting in a highly reliable SiC module or IGBT module.

[0072] In one embodiment, such as Figure 4 As shown, a semiconductor device packaging method is also provided, applied to the semiconductor device as described above. The semiconductor device packaging method includes:

[0073] Step S410: Place the metal preform on the substrate.

[0074] For example, a metal preform is picked up by a pick-up device (such as a pick-and-place machine), and the second sintered layer of the metal suppressor is precisely aligned and placed on the pads of the substrate.

[0075] Step S420: Place the chip to be mounted on the metal preform to form the first semi-finished product.

[0076] For example, the chip to be mounted is picked up by a pick-up device (such as a pick-and-place machine), and the chip to be mounted is precisely aligned and placed on the first sintering layer to obtain the first semi-finished product.

[0077] Step S430: Based on the second preset temperature, heat the first semi-finished product to cure the thermal decomposition bonding adhesive of the metal preform, so that the metal preform is at least pre-fixed to the chip or substrate to be mounted, in order to form the second semi-finished product.

[0078] The second preset temperature can be between 80°C and 120°C. It should be noted that the second preset temperature is lower than the first preset temperature.

[0079] Based on the heating device, the first semi-finished product is heated to a second preset temperature, which causes the thermal decomposition bonding adhesive of the metal preform to be fixed, thereby pre-fixing the metal preform at least on the chip or substrate to be mounted, preventing the chip or substrate to be mounted from falling off or shifting before or during sintering, and achieving precise and firm temporary fixation of the metal preform on the chip or substrate.

[0080] In some examples, the first sintered layer of the metal preform is provided with a first thermally decomposable bonding adhesive, and the second sintered layer of the metal preform is provided with a second thermally decomposable bonding adhesive. The first semi-finished product is heated based on a second preset temperature, and the first and second thermally decomposable bonding adhesives are cured, so that the chip to be mounted is pre-fixed to the first sintered layer of the metal preform by the first thermally decomposable bonding adhesive, and the second sintered layer of the metal preform is pre-fixed to the substrate by the second thermally decomposable bonding adhesive, forming a pre-interconnected second semi-finished product, thereby achieving precise and firm temporary fixation of the metal preform on the chip and the substrate.

[0081] Step S440: Based on the third preset temperature, the second semi-finished product is sintered to volatilize and decompose the thermal decomposition bonding adhesive of the metal preform, so that the metal preform connects the chip to be mounted and the substrate to obtain a semiconductor device.

[0082] The third preset temperature is greater than the first preset temperature.

[0083] For example, the second semi-finished product is placed in a sintering device, and the temperature of the sintering device is adjusted to a third preset temperature to sinter the second semi-finished product. During the sintering process, when the thermal decomposition bonding adhesive of the metal preform reaches the first preset temperature, the thermal decomposition bonding adhesive volatilizes and decomposes without any inorganic residue, allowing the metal preform to connect the chip to be mounted and the substrate, thereby obtaining a highly reliable semiconductor device. This avoids contamination of the chip by the thermal decomposition bonding adhesive, achieving reliable pre-interconnection and ensuring that the interconnection interface is completely free of contamination after sintering, thus improving the reliability of semiconductor device sintering.

[0084] In one embodiment, the thermally decomposable bonding adhesive of the metal preform is cured based on a second preset temperature, so that the metal preform is at least pre-fixed to the chip or substrate to be mounted, to form a second semi-finished product, including:

[0085] Based on a preset duration, preset pressure, and a second preset temperature, pressure is applied to the first semi-finished product to cure the thermal decomposition bonding adhesive of the metal preform and to pre-fix the metal preform at least to the chip or substrate to be mounted, so as to form the second semi-finished product.

[0086] The preset duration can be between 1 second and 2 seconds. The preset pressure can be between 1 MPa and 5 MPa.

[0087] The pressure device applies a preset pressure to the first semi-finished product, making the chip to be mounted, the metal preform, and the substrate tightly bonded together. The heating device heats the first semi-finished product to a second preset temperature and holds it at that temperature for a preset duration, so that the thermally decomposed bonding adhesive of the metal preform can be fixed. This ensures that the metal preform is at least pre-fixed on the chip to be mounted or the substrate, preventing the chip to be mounted or the substrate from falling off or shifting before or during sintering, and improving the firmness of the metal preform's pre-fixation on the chip or substrate.

[0088] It should be understood that, although Figure 4 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order in which these steps are executed, and they can be performed in other orders. Figure 4 At least some of the steps in the process may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least some of the sub-steps or stages of other steps.

[0089] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0090] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A packaging method of a semiconductor device, characterized by, The packaging method is applied to a semiconductor device, and comprises the following steps: arranging a metal preform on a substrate; arranging a chip to be mounted on the metal preform to form a first semi-finished product, wherein the metal preform comprises: a metal layer having opposite first and second surfaces; a first sintering layer arranged on the first surface of the metal layer; a second sintering layer arranged on the second surface of the metal layer; and a thermal decomposition adhesive arranged on at least one of the first sintering layer and the second sintering layer, the thermal decomposition adhesive being used to preliminarily fix the first sintering layer to the chip to be mounted or the second sintering layer to the substrate, and the thermal decomposition adhesive being used to produce volatile decomposition when sintering reaches a first preset temperature, so that the first sintering layer is connected to the chip to be mounted or the second sintering layer is connected to the substrate; based on a second preset temperature, heating the first semi-finished product to solidify the thermal decomposition adhesive of the metal preform, so that the metal preform is preliminarily fixed to at least one of the chip to be mounted and the substrate to form a second semi-finished product; based on a third preset temperature, sintering the second semi-finished product to volatilize and decompose the thermal decomposition adhesive of the metal preform, so that the metal preform is connected to the chip to be mounted and the substrate to obtain a semiconductor device.

2. The packaging method of a semiconductor device according to claim 1, wherein The method for packaging a semiconductor device comprises the following steps: based on a preset duration, a preset pressure and the second preset temperature, applying pressure to the first semi-finished product to solidify the thermal decomposition adhesive of the metal preform, so that the metal preform is preliminarily fixed to at least one of the chip to be mounted and the substrate to form the second semi-finished product.

3. A semiconductor device prepared by the encapsulation method according to any one of claims 1 to 2, characterized by The semiconductor device comprises a chip to be mounted, a substrate and a metal preform, wherein the metal preform preliminarily fixes at least one of the chip to be mounted and the substrate, so that the metal preform is connected to the chip to be mounted and the substrate when sintering reaches a first preset temperature. The metal preform comprises: a metal layer having opposite first and second surfaces; a first sintering layer arranged on the first surface of the metal layer; a second sintering layer arranged on the second surface of the metal layer; and a thermal decomposition adhesive arranged on at least one of the first sintering layer and the second sintering layer, the thermal decomposition adhesive being used to preliminarily fix the first sintering layer to the chip to be mounted or the second sintering layer to the substrate, and the thermal decomposition adhesive being used to produce volatile decomposition when sintering reaches a first preset temperature, so that the first sintering layer is connected to the chip to be mounted or the second sintering layer is connected to the substrate. The chip to be mounted is a SiC module to be mounted or an IGBT module to be mounted. The thermal decomposition adhesive comprises a first thermal decomposition adhesive and a second thermal decomposition adhesive, the first sintering layer is provided with at least two first coating areas, and the second sintering layer is provided with at least two second coating areas. ​ 4. The semiconductor device according to claim 3, wherein ​ 5. The semiconductor device of claim 3, wherein ​ Each of the first coating regions is provided with the first thermal decomposition bonding glue, and each of the second coating regions is provided with the second thermal decomposition bonding glue.

6. The semiconductor device according to claim 5, wherein The first coating regions are arranged adjacent to the side edges of the first sintering layer, and the distance between the first coating regions and the corresponding adjacent side edges of the first sintering layer is between 0.1 mm and 1 mm; The second coating regions are arranged adjacent to the side edges of the second sintering layer, and the distance between the second coating regions and the corresponding adjacent side edges of the second sintering layer is between 0.1 mm and 1 mm.

7. The semiconductor device of claim 5, wherein The first thermal decomposition bonding glue is a thermoplastic polymer or a thermoplastic oligomer. The second thermal decomposition bonding glue is a thermoplastic polymer or a thermoplastic oligomer.

8. The semiconductor device according to any one of Claims 3 to 7, wherein The metal layer includes a first metal plating layer, a second metal plating layer, and a metal sheet; The metal sheet has a first surface and a second surface, the first metal plating layer is arranged on the first surface of the metal sheet, and the second metal plating layer is arranged on the second surface of the metal sheet; The first sintering layer is arranged on the first metal plating layer, and the second sintering layer is arranged on the second metal plating layer.

9. The semiconductor device according to any one of Claims 3 to 7, wherein The first sintering layer includes silver particles of a first diameter, the first diameter being between 50 nm and 5 um in diameter, and the thickness of the first sintering layer being between 20 um and 100 um; The second sintering layer includes silver particles of a second diameter, the second diameter being between 50 nm and 5 um in diameter, and the thickness of the second sintering layer being between 20 um and 100 um.

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