CN118016539A - Preparation method of silicon carbide high-voltage silicon stack - Google Patents
Preparation method of silicon carbide high-voltage silicon stack Download PDFInfo
- Publication number
- CN118016539A CN118016539A CN202410424146.2A CN202410424146A CN118016539A CN 118016539 A CN118016539 A CN 118016539A CN 202410424146 A CN202410424146 A CN 202410424146A CN 118016539 A CN118016539 A CN 118016539A
- Authority
- CN
- China
- Prior art keywords
- welding
- silicon carbide
- voltage
- stack
- connecting sheet
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 title claims abstract description 99
- 229910052710 silicon Inorganic materials 0.000 title claims abstract description 99
- 239000010703 silicon Substances 0.000 title claims abstract description 99
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 title claims abstract description 82
- 229910010271 silicon carbide Inorganic materials 0.000 title claims abstract description 82
- 238000002360 preparation method Methods 0.000 title claims abstract description 9
- 238000003466 welding Methods 0.000 claims abstract description 132
- 238000004806 packaging method and process Methods 0.000 claims abstract description 13
- 229910052709 silver Inorganic materials 0.000 claims abstract description 9
- 239000004332 silver Substances 0.000 claims abstract description 9
- 238000007747 plating Methods 0.000 claims abstract description 8
- 238000004519 manufacturing process Methods 0.000 claims abstract description 7
- 229920006336 epoxy molding compound Polymers 0.000 claims abstract description 5
- 238000000034 method Methods 0.000 claims description 34
- 230000008569 process Effects 0.000 claims description 20
- 239000000463 material Substances 0.000 claims description 13
- 229910052751 metal Inorganic materials 0.000 claims description 9
- 239000002184 metal Substances 0.000 claims description 9
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 8
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 6
- QQMBHAVGDGCSGY-UHFFFAOYSA-N [Ti].[Ni].[Ag] Chemical compound [Ti].[Ni].[Ag] QQMBHAVGDGCSGY-UHFFFAOYSA-N 0.000 claims description 6
- 229910052802 copper Inorganic materials 0.000 claims description 6
- 239000010949 copper Substances 0.000 claims description 6
- 229910052737 gold Inorganic materials 0.000 claims description 6
- 239000010931 gold Substances 0.000 claims description 6
- MSNOMDLPLDYDME-UHFFFAOYSA-N gold nickel Chemical compound [Ni].[Au] MSNOMDLPLDYDME-UHFFFAOYSA-N 0.000 claims description 6
- 239000000758 substrate Substances 0.000 claims description 6
- 239000004642 Polyimide Substances 0.000 claims description 5
- 229920001721 polyimide Polymers 0.000 claims description 5
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims description 4
- BSIDXUHWUKTRQL-UHFFFAOYSA-N nickel palladium Chemical compound [Ni].[Pd] BSIDXUHWUKTRQL-UHFFFAOYSA-N 0.000 claims description 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 3
- 229910001873 dinitrogen Inorganic materials 0.000 claims 1
- 239000007789 gas Substances 0.000 claims 1
- 230000001681 protective effect Effects 0.000 claims 1
- 238000005476 soldering Methods 0.000 description 30
- 230000008901 benefit Effects 0.000 description 7
- 230000017525 heat dissipation Effects 0.000 description 7
- 239000011159 matrix material Substances 0.000 description 7
- 238000011084 recovery Methods 0.000 description 6
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 5
- 229910000679 solder Inorganic materials 0.000 description 4
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 3
- 230000009471 action Effects 0.000 description 3
- 238000010923 batch production Methods 0.000 description 3
- 239000000919 ceramic Substances 0.000 description 3
- 239000004033 plastic Substances 0.000 description 3
- 239000004593 Epoxy Substances 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 238000009413 insulation Methods 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 229910052750 molybdenum Inorganic materials 0.000 description 2
- 239000011733 molybdenum Substances 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 239000000741 silica gel Substances 0.000 description 2
- 229910002027 silica gel Inorganic materials 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 241000252254 Catostomidae Species 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
Landscapes
- Ceramic Products (AREA)
Abstract
The invention relates to the field of high-voltage silicon stacks, and discloses a preparation method of a silicon carbide high-voltage silicon stack, which comprises the steps of preparing a connecting sheet with a convex structure on the front surface and convex points on the convex structure, and plating silver on the surface of the connecting sheet; inserting a lower lead into a lower welding disc, repeatedly filling a welding lug, a silicon carbide chip, a welding lug and a connecting sheet in sequence from bottom to top, wherein the repeated times are that the number of the silicon carbide chips is reduced by one, sequentially filling the welding lug, the silicon carbide chip and the welding lug on the uppermost connecting sheet, closing an upper welding disc loaded with an upper lead, wherein the back surface of the silicon carbide chip faces the lower welding disc, and the front surface of the connecting sheet faces the lower welding disc and is opposite to the front surface of the silicon carbide chip in front of the connecting sheet; placing the high-voltage silicon stack into a welding furnace for welding according to the directions of the upper welding disk and the lower welding disk of the lower welding disk; and packaging the high-voltage silicon stack welding piece by adopting epoxy molding compound. The invention can obtain the silicon carbide high-voltage silicon stack which is high-temperature and high-pressure resistant, is applicable to ultrahigh frequency and small in volume and is easy for mass production.
Description
Technical Field
The invention relates to the technical field of high-voltage silicon stacks, in particular to a preparation method of a silicon carbide high-voltage silicon stack.
Background
The high-voltage silicon stack has the advantages of small volume, light weight, high mechanical strength, simple and convenient use, no radiation and the like, and has wide application in the medical field, the communication field, the aerospace field and the like. However, the existing silicon-based high-voltage silicon stack preparation process is generally as disclosed in China patent application number 201711248801X, and a plurality of chips are directly stitch-welded. The reverse recovery time of the high-voltage silicon is greatly changed along with the temperature, and is usually 75nS at the normal temperature of 25 ℃, but can reach more than 200nS at the temperature of 150 ℃.
In order to improve the high temperature resistance of the high-voltage silicon stack, some patents propose improvement schemes. For example, chinese patent No. 2022206848762 proposes stacking and sintering a plurality of chips by molybdenum sheets, and then packaging the chips by a silica gel seal and a ceramic housing, and although the technical scheme can improve the high temperature resistance of the high-voltage silicon stack in practical application to a certain extent by a ceramic packaging shell, the technical scheme does not improve the heat dissipation performance of the high-voltage silicon stack, and also does not consider the unreliable problem of the high-voltage silicon stack caused by thermal mismatch and partial discharge in the preparation process, and the size of the finished product is large.
In order to solve the problem of poor reliability of the high-voltage silicon stack in the existing welding process, china patent with the application number 2020103017885 proposes to stack a plurality of chips through molybdenum sheets and silver sheets and then press-bond the chips, and press-bond and package the high-voltage silicon stack through two fixing frames and positioning.
While some of the solutions described above have been directed to improving the high temperature resistance of high-voltage silicon stacks and have achieved some results, other problems, such as increased product size, increased costs, etc., have been introduced accordingly. Moreover, the current high-voltage silicon stack is generally invalid and cannot be used under the high-temperature condition of over 150 ℃; specifically, the current silicon-based high-voltage silicon stack has no work when the reverse direct current I R reaches several tens of mu A or even hundreds of mu A at 150 ℃. In addition, the existing high-voltage silicon stack is difficult to meet the use requirement of an ultrahigh-frequency high-voltage circuit with the frequency of 50 MHz.
The above disclosure of background art is only for aiding in understanding the inventive concept and technical solution of the present application, and it does not necessarily belong to the prior art of the present patent application, nor does it necessarily give technical teaching; the above background should not be used to assess the novelty and creativity of the present application in the event that no clear evidence indicates that such is already disclosed prior to the filing date of the present patent application.
Disclosure of Invention
The invention aims to provide a preparation method of a silicon carbide high-voltage silicon stack, which can obtain the silicon carbide high-voltage silicon stack with excellent heat dissipation performance, high temperature resistance, high pressure resistance, ultrahigh frequency and small volume and is easy for mass production.
In order to achieve the above purpose, the invention adopts the following technical scheme:
a preparation method of a silicon carbide high-voltage silicon stack comprises the following steps:
Preparing a connecting sheet, comprising preparing a connecting sheet matrix by adopting a copper material, wherein the front surface of the connecting sheet matrix is provided with a convex structure, the convex structure is provided with a plurality of convex points, and the surface of the connecting sheet matrix is provided with a silver plating layer;
assembling a high-voltage silicon stack, comprising inserting lower leads into lower welding discs, repeatedly filling welding chips, silicon carbide chips, welding chips and connecting sheets above each lower lead in the lower welding discs in sequence from bottom to top, wherein the repeated times are that the number of the silicon carbide chips in the high-voltage silicon stack is reduced by one, sequentially filling the welding chips, the silicon carbide chips and the welding chips on the uppermost connecting sheet, and then closing an upper welding disc loaded with upper leads, wherein the back surface of the silicon carbide chip faces the lower welding disc, and the convex structure of the connecting sheet faces the lower welding disc and the front surface of the silicon carbide chip below the lower welding disc;
welding the high-voltage silicon stack, namely putting the assembled high-voltage silicon stack into a welding furnace for welding according to the directions of the upper welding disk and the lower welding disk of the lower welding disk to form a high-voltage silicon stack welding piece;
and packaging the high-voltage silicon stack, and packaging the high-voltage silicon stack welding piece by adopting epoxy molding compound to prepare a silicon carbide high-voltage silicon stack finished product.
Further, in the foregoing any one or a combination of the foregoing aspects, the protruding structure has a structure that is contracted toward an extending direction thereof, and a projected area thereof is smaller than a frontal area of the connecting piece.
Further, in any one or a combination of the foregoing aspects, a projected area of the lug along an axis direction of the lug is not larger than a projected area of the bump structure along the axis direction of the lug.
Further, in any one or a combination of the foregoing technical solutions, a metal layer disposed on the front surface of the silicon carbide chip has nickel-gold or nickel-palladium-gold or titanium-nickel-silver; the metal layer arranged on the back of the silicon carbide chip is nickel gold or nickel palladium gold or titanium nickel silver.
Further, in any one or a combination of the foregoing technical solutions, the protruding points are uniformly distributed on an upper surface of the protruding structure.
Further, the back of the connecting sheet substrate is a planar structure; or alternatively
The back of the connecting sheet matrix comprises a plane structure and a bump structure arranged on the plane structure.
Further, in accordance with any one or a combination of the foregoing aspects, the front surface of the silicon carbide chip includes a bonding surface disposed in a middle region thereof and a guard ring disposed around the bonding surface.
Further, in any one or a combination of the foregoing aspects, the welding surface has a concave structure with respect to the protection ring;
The concave structure is matched with the convex structure, and in the welding process, a soldering lug arranged between the front surface of the connecting sheet and the front surface of the silicon carbide chip is fused between the welding surface and the convex structure and is not contacted with the protection ring.
Further, according to any one or a combination of the above-mentioned technical solutions, the material of the guard ring is polyimide.
Further, in the assembling of the high-voltage silicon stacks according to any one or a combination of the foregoing aspects, the method further includes checking and adjusting positions of the soldering lugs, the silicon carbide chips and the connecting pieces, so that centers of the soldering lugs, the silicon carbide chips and the connecting pieces in each high-voltage silicon stack are coincident.
Further, any one or a combination of the above technical solutions, the welding furnace vacuum-pumping and nitrogen-charging protection operation is further included in the welding process of the high-voltage silicon stack.
Further, according to any one or a combination of the above technical solutions, after the welding of the high-voltage silicon stack is completed, the welding furnace is opened to take out the high-voltage silicon stack welding piece after the air pressure in the welding furnace is reduced to normal pressure and the temperature is lower than 100 ℃.
The technical scheme provided by the invention has the following beneficial effects:
a. The invention designs a connecting sheet with a convex structure with convex points, the convex structure is attached to a soldering lug on the front surface of a chip, the front surface of the chip faces downwards during welding, and the chip is fused into a whole by adopting a tin-melting welding process, so that the problem of partial discharge between chips caused by poor contact can be solved, and the electric performance of a finished product is prevented from being influenced by solder flowing to a non-target welding area on the front surface of the chip;
b. According to the invention, the base material of the connecting sheet adopts copper with good electric conduction and heat conduction properties and low cost, the plating layer adopts silver with good electric conduction and heat conduction properties, the heat dissipation property of the silicon carbide high-voltage silicon stack in the use process can be improved through the connecting sheet, the heat generated by the chip can be quickly transferred to the connecting sheet, and the gap between the connecting sheet and the chip can be quickly dissipated, so that the high-temperature property of the silicon carbide high-voltage silicon stack is improved;
c. The invention adopts plastic package epoxy to package the high-voltage silicon stack welding piece, which not only can effectively solve the insulation problem of the chip gap, but also is easy to realize batch production, and has low material price and low process cost, thereby effectively improving economic benefit;
d. the silicon carbide high-voltage silicon stacking material provided by the application is compact, has small packaging structure size, can greatly reduce the product size, has low material cost and simple process, is easy to generate in batches, and has good economic benefit.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments described in the present application, and other drawings may be obtained according to the drawings without inventive effort to those skilled in the art.
FIG. 1 is a flow chart of a method for fabricating a silicon carbide high voltage silicon stack according to an exemplary embodiment of the present invention;
FIG. 2 is a graph of temperature versus reverse DC current for a silicon carbide high voltage silicon stack according to an exemplary embodiment of the present invention;
fig. 3 is a temperature-reverse recovery time graph of a silicon carbide high voltage silicon stack provided by an exemplary embodiment of the invention.
Detailed Description
In order that those skilled in the art will better understand the present invention, a technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and the claims of the present invention and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the invention described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, apparatus, article, or device that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed or inherent to such process, method, article, or device.
In one embodiment of the present invention, there is provided a method for preparing a silicon carbide high-voltage silicon stack, see fig. 1, the method comprising the steps of:
Preparing a connecting sheet, comprising preparing a connecting sheet matrix by adopting a copper material, wherein the front surface of the connecting sheet matrix is provided with a convex structure, the convex structure is provided with a plurality of convex points, the back surface of the convex structure is preferably a plane structure or is provided with a convex point structure, and the surface of the connecting sheet matrix is provided with a silver plating layer;
assembling a high-voltage silicon stack, comprising inserting lower leads into lower welding discs, repeatedly filling welding chips, silicon carbide chips, welding chips and connecting sheets above each lower lead in the lower welding discs in sequence from bottom to top, wherein the repeated times are that the number of the silicon carbide chips in the high-voltage silicon stack is reduced by one, the number of the silicon carbide chips in the high-voltage silicon stack is not less than two, then sequentially filling the welding chips, the silicon carbide chips and the welding chips on the uppermost connecting sheet, and then closing the upper welding disc loaded with upper leads, wherein the back surface of the silicon carbide chip faces the lower welding disc, and the convex structure of the connecting sheet faces the lower welding disc and the front surface of the silicon carbide chip below the lower welding disc;
welding the high-voltage silicon stack, namely putting the assembled high-voltage silicon stack into a welding furnace for welding according to the directions of the upper welding disk and the lower welding disk of the lower welding disk to form a high-voltage silicon stack welding piece;
and packaging the high-voltage silicon stack, and packaging the high-voltage silicon stack welding piece by adopting epoxy molding compound to prepare a silicon carbide high-voltage silicon stack finished product.
The core of the application is that a metal medium copper particle, namely the connecting sheet, is designed between two adjacent chips (hereinafter, the chips are abbreviated as silicon carbide chips), one surface of the connecting sheet is a convex structure with convex points, the convex structure is attached to a soldering lug on the front surface of the chip, the chips are fused into a whole by adopting a tin melting welding process, and in the welding process, the convex points form a certain gap between the front surface of the chip and the convex structure of the connecting sheet, so that molten soldering tin can flow uniformly and smoothly in the gap, and the problem of partial discharge between the chips caused by poor contact is solved. In addition, in the welding process, the soldering tin disc is inverted, so that the front surface of the chip faces downwards, molten soldering tin flows on the convex structure of the connecting sheet, and the phenomenon that the electric performance of a finished product is influenced due to the fact that the soldering tin flows to a non-target welding area on the front surface of the chip can be avoided.
And the base material of the connecting sheet adopts copper with low cost and good electric and heat conductivity, and the plating layer adopts silver with good electric and heat conductivity. Therefore, the heat dissipation performance of the silicon carbide high-voltage silicon stack in the use process can be improved through the connecting sheet, heat generated by the chip can be quickly transferred to the connecting sheet, and heat is quickly dissipated through the connecting sheet and a gap between the connecting sheet and the chip.
The invention adopts plastic package epoxy to package the high-voltage silicon stack welding piece, which not only can effectively solve the insulation problem of the chip gap, but also is easy to realize batch production, and has low material price and low process cost, thereby effectively improving economic benefit.
In summary, compared with the technical proposal provided by the China patent with the application number 2020103017885, the silver sheet and molybdenum sheet double-structure is needed between two adjacent chips because of adopting a frame with high price and complex structure, and special jigs are needed to realize the assembly and the compression joint of products, and the batch production is difficult; compared with the technical proposal provided by China patent with the application number 2022206848762, partial discharge possibly existing between chips due to poor contact, poor heat dissipation performance, high cost and large product size due to the need of a silica gel sealing layer and a ceramic shell for packaging; the technical scheme provided by the application has the advantages of low material cost, compact structure, simple assembly and easiness in batch generation, and can solve the problem of partial discharge of chips, effectively improve the heat dissipation performance of products, improve the high-temperature performance of the products, greatly reduce the cost and reduce the size of the products. Therefore, the silicon carbide high-voltage silicon stack provided by the application has the characteristics of good electrical property, small volume, reliable heat dissipation performance, higher integration, more suitable mass production, high economic cost ratio and the like.
The following is a detailed description of the assembling and welding steps of the silicon carbide high-voltage silicon stack in the mass production process of the silicon carbide high-voltage silicon stack provided by the invention, taking a silicon carbide high-voltage silicon stack with 2 particles (two silicon carbide chips in one high-voltage silicon stack) as an example:
(1) Inserting a lower lead, namely inserting the lower lead into a lower welding disc, wherein a plurality of dozens, hundreds or thousands of holes can be formed in one lower welding disc, and each hole is correspondingly inserted with one lower lead;
(2) Shaking the soldering lug, putting the soldering lug into a sucking disc, shaking uniformly, starting suction, sucking the soldering lug through the sucking disc, pouring out redundant soldering lug, transferring the soldering lug to a lower soldering lug, and checking and adjusting to enable one soldering lug to fall into a hole corresponding to each lower lead;
(3) Filling chips, namely, filling the chips into a graphite disc in the same direction by using a vacuum suction pen or plastic tweezers, filling the chips in large batches by using a die bonder, and checking and adjusting the positions of the chips to ensure that the front side and the back side of the chips face upwards and are attached to the soldering lugs, wherein one chip is arranged in a hole corresponding to each lead, namely, one chip is arranged on each soldering lug;
(4) Shaking the soldering lug, namely repeating the step (2), and correspondingly filling a soldering lug above each chip;
(5) Shaking the connecting pieces, putting the connecting pieces into the suckers, shaking the connecting pieces uniformly, starting suction force, adsorbing the connecting pieces and pouring out redundant connecting pieces, and similarly, arranging one connecting piece in a hole corresponding to each lead, namely falling into one connecting piece on each soldering lug, checking and adjusting the positions of the connecting pieces to enable the back surfaces of the connecting pieces to face upwards and the protruding structures to face downwards to be attached to the soldering lugs below the connecting pieces;
(6) Shaking the welding pieces, namely repeating the step (2), and correspondingly filling one welding piece above each connecting piece;
(7) Filling chips, namely repeating the step (3), and correspondingly filling one chip above each soldering lug;
(8) Shaking the soldering lug, namely repeating the step (2), and correspondingly filling a soldering lug above each chip;
(9) Assembling the welding disc, covering the upper welding disc assembled with the upper lead on the lower welding disc, and turning the assembled welding disc up and down by 180 degrees to enable the front surface of the chip to face downwards and the protruding structure of the connecting sheet to face upwards; during the process of assembling the high-voltage silicon stacks, the positions of the soldering lugs, the silicon carbide chips and the connecting sheets are checked and adjusted, so that the centers of the soldering lugs, the silicon carbide chips and the connecting sheets in each high-voltage silicon stack are overlapped;
(10) Adjusting and setting welding furnace equipment according to welding requirements, placing a welding disc in a welding furnace for welding to form a high-voltage silicon stack welding piece; the welding furnace is vacuumized and nitrogen is filled for protecting during the welding of the high-voltage silicon stack; after the welding of the high-voltage silicon stack is finished, opening the welding furnace to take out the welding piece of the high-voltage silicon stack after the air pressure in the welding furnace is reduced to normal pressure and the temperature is lower than 100 ℃ so as to avoid scalding when the material is oxidized and taken out due to the over-high temperature;
(11) And packaging the high-voltage silicon stack, and packaging the high-voltage silicon stack welding piece by adopting epoxy molding compound to prepare a silicon carbide high-voltage silicon stack finished product.
It should be noted that, the specification of the silicon carbide high-voltage silicon stack provided in the invention is determined according to actual needs, and the number of the included chips can be any number of 2-11 or other numbers.
In one embodiment of the invention, the projection structure has a structure which is contracted toward the extending direction thereof, and the projected area thereof is smaller than the front area of the connection piece. The salient points are uniformly distributed on the upper surface of the protruding structure. The projection area of the soldering lug along the axis direction is not larger than the projection area of the convex structure along the axis direction.
At present, silicon carbide chips on the market are generally front-side aluminum and back-side silver, and are not suitable for a welding process. Therefore, the metal layer for welding, which is arranged on the front surface of the silicon carbide chip, is nickel gold or nickel palladium gold or titanium nickel silver; the back of the metal layer is also provided with a metal layer for welding, and the metal layer is nickel-gold or nickel-palladium-gold or titanium-nickel-silver so as to achieve excellent welding effect.
The front surface of the silicon carbide chip comprises a welding surface arranged in the middle area and a protection ring arranged around the welding surface. The material of the protection ring is preferably polyimide. In this embodiment, the polyimide layer may be disposed around the front plating layer of the chip, and the area without the polyimide layer in the middle of the front plating layer of the chip is a soldering surface. The area of the welding surface is not smaller than the upper surface area of the protruding structure. During welding, the convex structure and the front weldable surface of the chip are welded through molten solder, the front of the chip is arranged above and below the convex structure, the solder smoothly flows in a cavity gap brought by the convex point and on the convex structure, the phenomenon that the front protection ring of the chip is influenced after the solder is melted can be avoided, and the reliability of products can be improved and the situation of partial discharge can be avoided.
In one embodiment of the present invention, unlike the above embodiment in which the guard ring is only a thin film protruding from the welding surface, in this embodiment, the welding surface is in a concave structure with respect to the guard ring. Preferably, the concave structure is matched with the convex structure, and during welding, a soldering lug arranged between the front surface of the connecting sheet and the front surface of the silicon carbide chip is fused between the welding surface and the convex structure and is not contacted with the protection ring. The advantage of this embodiment is that the size of the silicon carbide high-voltage silicon stack can be further reduced.
The silicon carbide high-voltage silicon stack provided by the invention has low forward voltage drop with positive temperature coefficient characteristic, and the using temperature range is-55 ℃ to +175 ℃. The silicon carbide high-voltage silicon stack has excellent performance stability and excellent high-voltage high-frequency characteristics under the high-temperature condition, and the reverse recovery time of the silicon carbide high-voltage silicon stack is not more than 20nS at the reverse voltage of 8000V and above. The high-temperature reverse bias data of the silicon carbide high-voltage silicon stack provided by the invention is shown in figure 2, and under the condition that the reverse voltage VR is 8KV, the reverse direct current I R of the silicon carbide high-voltage silicon stack is less than 1 mu A at 150 ℃ after testing. The high frequency performance of the silicon carbide high voltage silicon stack has extremely excellent reverse recovery time, namely high frequency characteristic, as shown in fig. 3, and the reverse recovery time trr is nanosecond level and lower than 20nS under the test condition that the forward direct current I F is 0.5A, the reverse direct current I R is 1.0A and the reverse recovery current I RR is 0.25A.
The silicon carbide high-voltage silicon stack provided by the invention has the advantages of excellent heat radiation performance, high temperature resistance, high voltage resistance, ultrahigh frequency and small volume, and can meet the requirement of an ultrahigh frequency high-voltage circuit with the frequency of up to 50 MHz. The device can be widely applied to the fields of ultrahigh frequency laser radar, controllable nuclear fusion driving power supply, nanosecond or picosecond pulse power supply, electron and proton accelerator, laser electromagnetic emission power supply, ultrahigh frequency plasma power supply, high-end CT image, aerospace emission ignition device and the like.
It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
The foregoing is merely illustrative of the embodiments of this application and it will be appreciated by those skilled in the art that variations and modifications may be made without departing from the principles of the application, and it is intended to cover all modifications and variations as fall within the scope of the application.
Claims (9)
1. The preparation method of the silicon carbide high-voltage silicon stack is characterized by comprising the following steps of:
Preparing a connecting sheet, wherein the connecting sheet comprises a connecting sheet substrate made of copper material, wherein the front surface of the connecting sheet substrate is provided with a convex structure, the convex structure is provided with a plurality of convex points, the back surface of the connecting sheet substrate is of a planar structure, and the surface of the connecting sheet substrate is provided with a silver plating layer;
Assembling a high-voltage silicon stack, comprising inserting lower leads into lower welding discs, repeatedly filling welding chips, silicon carbide chips, welding chips and connecting sheets above each lower lead in the lower welding discs in sequence from bottom to top, wherein the number of times of repetition is reduced by one for the number of the silicon carbide chips in the high-voltage silicon stack, sequentially filling the welding chips, the silicon carbide chips and the welding chips on the uppermost connecting sheet, and then closing the upper welding disc loaded with the upper leads, wherein the back surface of the silicon carbide chip faces the lower welding discs, the convex structure of the connecting sheet faces the lower welding discs and the front surface of the silicon carbide chip below the lower welding discs, and a metal layer arranged on the front surface of the silicon carbide chip is nickel gold or nickel palladium gold or titanium nickel silver; the metal layer arranged on the back of the silicon carbide chip is nickel gold or nickel palladium gold or titanium nickel silver, the front of the silicon carbide chip comprises a welding surface arranged in the middle area and a protection ring arranged around the welding surface, and the protection ring is made of polyimide;
Welding a high-voltage silicon stack, namely putting the assembled high-voltage silicon stack into a welding furnace for welding according to the directions of the upper welding disk and the lower welding disk of the lower welding disk to form a high-voltage silicon stack welding piece, wherein in the welding process, a welding lug arranged between the front surface of the connecting sheet and the front surface of the silicon carbide chip is fused between the welding surface and the raised structure and is not contacted with the protection ring;
and packaging the high-voltage silicon stack, and packaging the high-voltage silicon stack welding piece by adopting epoxy molding compound to prepare a silicon carbide high-voltage silicon stack finished product.
2. The method of producing a silicon carbide high voltage silicon stack according to claim 1, wherein the convex structure has a structure that is contracted toward an extending direction thereof and has a projected area smaller than a front surface area of the connecting piece.
3. The method of producing a silicon carbide high voltage silicon stack according to claim 1, wherein a projected area of the lug in an axial direction thereof is not larger than a projected area of the bump structure in an axial direction thereof.
4. The method of claim 1, wherein the bumps are uniformly distributed on the upper surface of the bump structure.
5. The method of claim 1, wherein the back surface of the connecting piece substrate comprises a planar structure and a bump structure disposed on the planar structure.
6. The method of manufacturing a silicon carbide high voltage silicon stack according to claim 1, wherein the bonding surface has a concave structure with respect to the guard ring; the concave structure is matched with the convex structure.
7. The method of claim 1, further comprising inspecting and adjusting the position of each of the bonding pads, silicon carbide chips, and bond pads during assembly of the silicon carbide stack such that the centers of each of the bonding pads, silicon carbide chips, and bond pads in each of the silicon carbide stacks coincide.
8. The method for producing a silicon carbide high-voltage silicon stack according to claim 1, further comprising the protective operation of evacuating and charging nitrogen gas to the welding furnace during the welding of the high-voltage silicon stack.
9. The method for producing a silicon carbide high-voltage silicon stack according to claim 1, wherein after the welding of the high-voltage silicon stack is completed, the welding furnace is opened to take out the high-voltage silicon stack welding piece after the gas pressure in the welding furnace is reduced to normal pressure and the temperature is lower than 100 ℃.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410424146.2A CN118016539A (en) | 2024-04-10 | 2024-04-10 | Preparation method of silicon carbide high-voltage silicon stack |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410424146.2A CN118016539A (en) | 2024-04-10 | 2024-04-10 | Preparation method of silicon carbide high-voltage silicon stack |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN118016539A true CN118016539A (en) | 2024-05-10 |
Family
ID=90956800
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202410424146.2A Pending CN118016539A (en) | 2024-04-10 | 2024-04-10 | Preparation method of silicon carbide high-voltage silicon stack |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN118016539A (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN206236666U (en) * | 2016-11-01 | 2017-06-09 | 常州佳讯光电产业发展有限公司 | High-reliability high silicon stack |
| CN107887281A (en) * | 2017-12-01 | 2018-04-06 | 山东理工大学 | A kind of manufacture method and high voltage silicon rectifier stack of low-power consumption high-speed switch plastic sealed high-voltage silicon stack |
| CN111463191A (en) * | 2020-04-16 | 2020-07-28 | 华中科技大学 | Stack type crimping packaging structure of silicon carbide DSRD |
| CN116169035A (en) * | 2022-12-29 | 2023-05-26 | 江苏华创微系统有限公司 | Preparation method of chip-to-chip interconnectable stacked structure of flip chip and forward chip |
| CN117712053A (en) * | 2023-12-14 | 2024-03-15 | 江苏云意电气股份有限公司 | High-reliability chip and manufacturing method thereof |
-
2024
- 2024-04-10 CN CN202410424146.2A patent/CN118016539A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN206236666U (en) * | 2016-11-01 | 2017-06-09 | 常州佳讯光电产业发展有限公司 | High-reliability high silicon stack |
| CN107887281A (en) * | 2017-12-01 | 2018-04-06 | 山东理工大学 | A kind of manufacture method and high voltage silicon rectifier stack of low-power consumption high-speed switch plastic sealed high-voltage silicon stack |
| CN111463191A (en) * | 2020-04-16 | 2020-07-28 | 华中科技大学 | Stack type crimping packaging structure of silicon carbide DSRD |
| CN116169035A (en) * | 2022-12-29 | 2023-05-26 | 江苏华创微系统有限公司 | Preparation method of chip-to-chip interconnectable stacked structure of flip chip and forward chip |
| CN117712053A (en) * | 2023-12-14 | 2024-03-15 | 江苏云意电气股份有限公司 | High-reliability chip and manufacturing method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US20110244636A1 (en) | Manufacturing method of semiconductor chip-embedded wiring substrate | |
| JP5807348B2 (en) | Semiconductor device and manufacturing method thereof | |
| US20110298020A1 (en) | Semiconductor device | |
| US7518205B2 (en) | Semiconductor package and method for manufacturing the same | |
| US5786548A (en) | Hermetic package for an electrical device | |
| JP2002359345A (en) | Semiconductor device and its manufacturing method | |
| WO2021128958A1 (en) | Encapsulation structure and encapsulation method for digital circuit | |
| JP2012074497A (en) | Circuit board | |
| CN114743947B (en) | TO-form-based power device packaging structure and packaging method | |
| CN107078118A (en) | Coupling of the inserter to package substrate | |
| CN107749399B (en) | Power chip packaging method and structure | |
| CN112885804B (en) | Surface mount photovoltaic bypass module and packaging process thereof | |
| CN118016539A (en) | Preparation method of silicon carbide high-voltage silicon stack | |
| US3476986A (en) | Pressure contact semiconductor devices | |
| CN109273371A (en) | A kind of encapsulating structure of power semiconductor part and packaging method | |
| JP3780222B2 (en) | Hollow sealing package and manufacturing method thereof | |
| US11791232B2 (en) | Packaging structure and packaging method of digital circuit | |
| US20200144079A1 (en) | Semiconductor encapsulation structure | |
| CN104319242A (en) | Thick film substrate welding-flux-free eutectic crystal mounting method | |
| CN108878391A (en) | Intelligent power module structure and its manufacturing method | |
| CN221201173U (en) | Silicon carbide high-voltage silicon stack | |
| CN210778574U (en) | DBC structure suitable for high-voltage power device module packaging | |
| CN112185916A (en) | Double-channel air tightness packaging structure of flip chip and technology thereof | |
| US20220001475A1 (en) | Method for connection by brazing enabling improved fatigue resistance of brazed joints | |
| CN105633041A (en) | High-power thyristor package structure and manufacturing method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |