阅读说明：本技术 内绝缘封装结构及其工艺方法 (Internal insulation packaging structure and process method thereof ) 是由 戚丽娜 俞义长 赵善麒 于 2020-08-24 设计创作，主要内容包括：本发明提供一种内绝缘封装结构及其工艺方法,所述内绝缘封装结构包括：铜框架,框架包括载片台和引线框架,载片台的一面通过焊料与芯片进行焊接；绝缘装置,绝缘装置的一面通过焊料与载片台的另一面焊接,绝缘装置未与载片台焊接部分的绝缘片厚度大于绝缘装置与所述载片台焊接部分的绝缘片厚度；塑封材料,绝缘装置的另一面与塑封材料结合,塑封材料包围芯片、载片台和绝缘装置,且露出绝缘装置未与载片台焊接部分的金属部分绝缘装置。本发明利用绝缘装置周边绝缘材料的厚边处理,在增加了绝缘片的强度的同时又不增加热阻,且无需设置底部铜框架,节省一次焊接工艺和原材料,降低了生产成本和物料成本,且容易实现量产。(The invention provides an internal insulation packaging structure and a process method thereof, wherein the internal insulation packaging structure comprises the following components: the copper frame comprises a chip carrier and a lead frame, wherein one surface of the chip carrier is welded with the chip through welding flux; one surface of the insulating device is welded with the other surface of the slide holder through welding flux, and the thickness of an insulating sheet of a part of the insulating device which is not welded with the slide holder is larger than that of the part of the insulating device which is welded with the slide holder; and the other surface of the insulating device is combined with the plastic packaging material, the plastic packaging material surrounds the chip, the slide holder and the insulating device, and the metal part insulating device of the part, which is not welded with the slide holder, of the insulating device is exposed. The invention utilizes the thick edge treatment of the insulating material at the periphery of the insulating device, increases the strength of the insulating sheet without increasing thermal resistance, does not need to arrange a bottom copper frame, saves one-time welding process and raw materials, reduces the production cost and the material cost, and is easy to realize mass production.)

1. An inter-insulating package structure, comprising:

the chip mounting structure comprises a copper frame, a chip mounting plate and a chip mounting plate, wherein the copper frame comprises a chip carrying table and a lead frame, one surface of the chip carrying table is welded with a chip through welding flux, and the size of the chip carrying table is larger than that of the chip;

the insulating device comprises an insulating sheet and metal covering the surface of the insulating sheet, the size of the insulating device is larger than that of the slide holder, one surface of the insulating device is welded with the other surface of the slide holder through welding flux, and the thickness of the insulating sheet of the part of the insulating device which is not welded with the slide holder is larger than that of the part of the insulating device which is not welded with the slide holder;

and the other surface of the insulating device is combined with the plastic packaging material, the plastic packaging material surrounds the chip, the slide holder and the insulating device, and the metal of the part, which is not welded with the slide holder, of the insulating device is exposed.

2. The inner insulation package structure according to claim 1, wherein the insulation sheet of the insulation device not welded to the stage has a thickness of 2-5 mm.

3. The inner insulation package structure of claim 1, wherein the insulation sheet of the welded portion between the insulation device and the stage has a thickness of 0.25-0.5 mm, and the metal covering the surface of the insulation sheet has a thickness of 0.25-0.5 mm.

4. The inter-insulation package structure of claim 1, wherein the insulation sheet comprises a ceramic, and the metal covering the surface of the insulation sheet comprises copper.

5. A process method of an internal insulation packaging structure is characterized by comprising the following steps:

providing a copper frame, wherein the copper frame comprises a chip carrying table and a lead frame, and welding one surface of the chip carrying table with a chip through welding flux, wherein the size of the chip carrying table is larger than that of the chip;

providing an insulating device which comprises an insulating sheet and metal covering the surface of the insulating sheet, and welding one surface of the insulating device with the other surface of the slide holder by the welding flux, wherein the size of the insulating device is larger than that of the slide holder, and the thickness of the insulating sheet at the part of the insulating device which is not welded with the slide holder is larger than that of the insulating sheet at the part of the insulating device which is not welded with the slide holder;

and providing a plastic package material, combining the other surface of the insulating device with the plastic package material, surrounding the chip, the slide holder and the insulating device through the plastic package material, and exposing the metal of the part, which is not welded with the slide holder, of the insulating device.

6. The process method of claim 5, wherein the thickness of the insulation sheet of the insulation device not welded to the stage is 2-5 mm.

7. The process of claim 5, wherein the thickness of the insulation sheet of the welded portion of the insulation device and the stage is 0.25-0.5 mm, and the thickness of the metal is 0.25-0.5 mm.

8. The process of claim 5, wherein the insulating sheet comprises ceramic, and the metal covering the surface of the insulating sheet comprises copper.

Technical Field

The invention relates to the technical field of semiconductor packaging, in particular to an internal insulation packaging structure and a process method of the internal insulation packaging structure.

Background

In practical application, in an occasion with a high heat dissipation requirement, a heat sink is required to be attached to the back surface of a discrete device, and then, in order to ensure the insulation performance of the power device in a high-voltage environment, an insulation measure is required to separate a lead frame from the heat sink in the manufacturing process. There are two general approaches:

1. the ceramic wafer is attached to the back of the discrete device, but the method has the defects that the ceramic wafer has different insulation performance and needs a complicated inspection flow, in addition, the ceramic wafer is attached to the outside, the manufacturing flow is complicated, the yield is low, the cost is higher, the ceramic wafer is exposed at the outside, and the ceramic wafer is easy to collide and break in the transportation and installation processes, so that the insulation performance is influenced.

2. The sandwich inner insulation structure is characterized in that the plastic package material adopts two layers of copper frames, one layer is used for chip welding, the other layer is used for back heat dissipation, and double-sided copper-clad ceramic sheets are used for insulation and isolation in the two layers of copper frames. Compared with the scheme of sticking the ceramic plates outside, the scheme has higher reliability and is easier to realize mass production, but the scheme adds a welding layer, the thermal resistance is increased, and the cost is also increased due to the other two layers of thick frames.

Disclosure of Invention

In order to solve the technical problems, the invention provides an internal insulation packaging structure, which increases the strength of an insulation sheet without increasing thermal resistance by using the thick edge treatment of an insulation material at the periphery of an insulation device, does not need to arrange a bottom copper frame, saves one-time welding process and raw materials, reduces the production cost and the material cost, and is easy to realize mass production.

The technical scheme adopted by the invention is as follows:

an embodiment of a first aspect of the present invention provides an internal insulation package structure, including: the copper frame comprises a chip carrying table and a lead frame, wherein one surface of the chip carrying table is welded with a chip through welding flux, and the size of the chip carrying table is larger than that of the chip; the insulating device comprises an insulating sheet and metal covering the surface of the insulating sheet, the size of the insulating device is larger than that of the slide holder, one surface of the insulating device is welded with the other surface of the slide holder through welding flux, and the thickness of the insulating sheet of the part of the insulating device which is not welded with the slide holder is larger than that of the insulating sheet of the part of the insulating device which is not welded with the slide holder; and the other surface of the insulating device is combined with the plastic packaging material, the plastic packaging material surrounds the chip, the slide holder and the insulating device, and a metal part of the part, which is not welded with the slide holder, of the insulating device is exposed.

The internal insulation packaging structure provided by the invention also has the following additional technical characteristics:

according to one embodiment of the invention, the thickness of the insulating sheet at the part, which is not welded with the slide holder, of the double-sided metal ceramic is 2-5 mm.

According to one embodiment of the invention, the thickness of the insulation sheet of the welding part of the insulation device and the slide holder is 0.25-0.5 mm, and the thickness of the metal is 0.25-0.5 mm.

According to one embodiment of the present invention, the insulating sheet comprises a ceramic, and the metal overlying the surface of the insulating sheet comprises copper. The embodiment of the second aspect of the invention provides a process method of an internal insulation packaging structure, which comprises the following steps: providing a copper frame, wherein the copper frame comprises a chip carrying table and a lead frame, and welding one surface of the chip carrying table with a chip through welding flux, wherein the size of the chip carrying table is larger than that of the chip; providing an insulating device which comprises an insulating sheet and metal covering the surface of the insulating sheet, and welding one surface of the insulating device with the other surface of the slide holder by the welding flux, wherein the size of the insulating device is larger than that of the slide holder, and the thickness of the insulating sheet at the part of the insulating device which is not welded with the slide holder is larger than that of the insulating sheet at the part of the insulating device which is not welded with the slide holder; and providing a plastic package material, combining the other surface of the insulating device with the plastic package material, surrounding the chip, the slide holder and the insulating device through the plastic package material, and exposing a metal part of a part of the insulating device which is not welded with the slide holder.

According to one embodiment of the invention, the thickness of the insulation sheet at the welding part of the insulation device and the slide holder is 2-5 mm.

According to one embodiment of the invention, the thickness of the insulation sheet of the welding part of the insulation device and the slide holder is 0.25-0.5 mm, and the thickness of the metal is 0.25-0.5 mm.

According to one embodiment of the present invention, the insulating sheet comprises a ceramic, and the metal overlying the surface of the insulating sheet comprises copper. The invention has the beneficial effects that:

according to the invention, the thick edge treatment of the insulating material at the periphery of the insulating device is utilized, the strength of the insulating sheet is increased, the thermal resistance is not increased, a bottom copper frame is not required to be arranged, one-time welding process and raw materials are saved, the production cost and the material cost are reduced, the mass production is easy to realize, and only the metal part of the insulating device, which is not welded with the slide holder, is exposed during the packaging of the plastic packaging material, so that the insulation between the chip and the back radiator is realized, and the good heat dissipation between the back structure and the radiator is also realized.

Drawings

FIG. 1 is a cross-sectional view of an inter-insulating package structure in the related art;

FIG. 2 is a cross-sectional view of an inter-insulating package structure according to one embodiment of the invention;

FIG. 3 is a schematic structural view of an insulation unit according to one embodiment of the present invention;

FIG. 4 is a top view of an inner insulation package structure according to one embodiment of the present invention;

fig. 5 is a flow chart of a process method of an inter-insulating packaging structure according to one embodiment of the invention.

Detailed Description

The present inventors have made a study and recognition of the following problems:

as shown in fig. 1, the sandwich internal insulation scheme, i.e., the chip 101 to the copper frame 102, the copper frame 102 to the double-sided copper-clad ceramic sheet 103, and the double-sided copper-clad ceramic sheet 103 to the back copper frame 102, is subjected to three times of soldering processes in total, the three layers of solder 105 introduce an increase in thermal resistance, and the process cost and the material cost are high. The chip 101 goes to a copper frame 102, whose thickness is to ensure the passage of a large current, and therefore cannot be thinned. The thickness of the ceramic wafer is 0.25-0.5 mm, the thickness of the ceramic wafer directly influences thermal resistance, so the ceramic wafer is not suitable to be thick, the thickness of the double-sided copper-coated ceramic wafer is 0.25-0.5 mm, and the whole material of the double-sided copper-coated ceramic wafer 103 is fragile. The back copper frame 102 is for mounting to a heat sink, and the thickness is not required. However, if the copper frame is directly cancelled, only the thin copper covered by the ceramic wafer is relied on, and quality hidden troubles such as cracking and the like are easily caused in the later packaging and stamping process.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Fig. 2 is a schematic cross-sectional view of an inter-insulating package structure according to an embodiment of the present invention, as shown in fig. 2, the inter-insulating package structure includes: copper frame 2, insulator arrangement 3 and plastic envelope material 4.

The copper frame 2 comprises a chip carrier 21 and a lead frame 22, one surface of the chip carrier 21 is welded with the chip 1 through a solder 5, and the size of the chip carrier 21 is larger than that of the chip 1; the insulating means 3 may comprise: the size of the insulating device 3 is larger than that of the slide holder 21, one surface of the insulating device 3 is welded with the other surface of the slide holder 21 through welding flux 5, wherein the thickness a1 of the insulating sheet of the part of the insulating device 3 which is not welded with the slide holder 21 is larger than the thickness a2 of the insulating sheet of the part of the insulating device 3 which is welded with the slide holder 21; the other surface of the insulating device 3 is combined with the plastic package material 4, the plastic package material 4 surrounds the chip 1, the slide holder 21 and the insulating device 3, and metal of the part, which is not welded with the slide holder 21, of the insulating device 3 is exposed, so that the insulation between the chip and the back radiator is realized, and the good heat dissipation between the back structure and the radiator is also realized.

Specifically, as shown in fig. 2, the stage 21 is used to hold the chip 1, so the size of the stage 21 is larger than that of the chip 1, and the lead frame 22 is used for pin extraction and functions as a common discrete device pin. One surface of the insulating device 3 is welded with the slide holder 21 through the solder 5, and the other surface of the insulating sheet 3 is combined with the plastic package material 4. Wherein, as shown in fig. 3, the insulation device 3 may include: an insulating sheet 31 and a metal 32 covering the surface of the insulating sheet, the size of the insulating device 3 is larger than that of the slide stage 21, and the thickness a1 of the insulating sheet at the part of the insulating device 3 which is not welded with the slide holder 21 is larger than the thickness a2 of the insulating sheet at the part of the insulating device 3 which is welded with the slide holder 21, that is, the thickness of the insulating material in the non-chip-bearing region of the insulating device 3 is increased, which contributes to the thermal resistance to a negligible extent, but increases the overall strength of the insulating device, and by using the existing packaging process, the whole set of packaging can be realized, but the welding from the insulating sheet to the back copper frame can be saved, the thermal resistance is reduced, the packaging characteristic is improved, the cost is saved, the production efficiency is improved, and only the metal part of the insulation device, which is not welded with the slide holder, is exposed during packaging by the plastic packaging material, so that the insulation between the chip and the back radiator is realized, and the good heat dissipation between the back structure and the radiator is also realized.

The top view of the inner insulation package structure can be seen in fig. 4, wherein the region D is a thickened region of the insulation material in the non-chip-carrying region of the insulation device 3.

It can be understood that the part of the insulating sheet where the insulating device 3 is not welded to the stage 21 has a thickness a1 greater than the thickness a2 of the insulating sheet where the insulating device 3 is welded to the stage 21, and the part may be formed in one step or may be formed by sintering, welding or coating, i.e. the thickened part may be formed in one step or may be formed by sintering, welding or coating at a later stage to thicken the insulating material at a given position.

In a specific example of the present invention, the thickness a1 of the insulating sheet 31 at the portion of the insulating device 3 not welded to the stage 21 may be 2 to 5 mm.

In the embodiment of the invention, the thickness of the insulation sheet at the welding part of the insulation device 3 and the slide holder 21 can be 0.25-0.5 mm, and the thickness of the metal can be 0.25-0.5 mm.

In the embodiment of the present invention, the insulating sheet 31 may be made of any material capable of achieving insulation, such as ceramic, polyimide, rubber, etc., and the metal 32 coated on the surface of the insulating sheet may be made of any material capable of achieving protection of the insulating material and attachment of the heat sink, such as copper, aluminum, gold, etc., and in consideration of characteristics, cost and production feasibility, ceramic plus copper is a currently good choice, i.e., the insulating sheet is made of ceramic, and the metal 32 coated on the surface of the insulating sheet is made of copper.

In summary, according to the internal insulation package structure of the embodiment of the invention, one surface of the stage of the copper frame is welded to the chip by the solder, and one surface of the insulation device is welded to the other surface of the stage by the solder, wherein the insulation sheet at the portion of the insulation device not welded to the stage is thicker than the insulation sheet at the portion of the insulation device welded to the stage, and the other surface of the insulation device is bonded to the molding compound, which surrounds the chip, the stage and the insulation device and exposes the metal at the portion of the insulation device not welded to the stage. According to the invention, the thick edge treatment of the insulating material at the periphery of the insulating device is utilized, the strength of the insulating sheet is increased, the thermal resistance is not increased, a bottom copper frame is not required to be arranged, one-time welding process and raw materials are saved, the production cost and the material cost are reduced, the mass production is easy to realize, and only the metal part of the insulating device, which is not welded with the slide holder, is exposed during the packaging of the plastic packaging material, so that the insulation between the chip and the back radiator is realized, and the good heat dissipation between the back structure and the radiator is also realized.

Corresponding to the above-mentioned internal insulation package structure, the present invention further provides a process method for an internal insulation package structure, and since the method embodiment of the present invention corresponds to the above-mentioned structure embodiment, details that are not disclosed in the method embodiment may refer to the above-mentioned structure embodiment, and are not described again in the present invention.

Fig. 5 is a flow chart of a process method of an inter-insulating packaging structure according to one embodiment of the invention. As shown in fig. 5, the method comprises the steps of:

and S1, providing a copper frame, wherein the copper frame comprises a chip carrier and a lead frame, and welding one surface of the chip carrier with the chip through solder. Wherein, the size of the slide holder is larger than that of the chip.

And S2, providing an insulating device, wherein the insulating device comprises an insulating sheet and metal covering the surface of the insulating sheet, and welding one surface of the insulating device with the other surface of the slide holder by welding flux, wherein the size of the insulating device is larger than that of the slide holder, and the thickness of the insulating sheet at the part of the insulating device which is not welded with the slide holder is larger than that of the insulating sheet at the part of the insulating device which is welded with the slide holder.

And S3, providing a plastic package material, combining the other surface of the insulating device with the plastic package material, surrounding the chip, the slide holder and the insulating device through the plastic package material, and exposing the metal of the part of the insulating device, which is not welded with the slide holder.

In one embodiment of the invention, the thickness of the insulating sheet at the part of the insulating device which is not welded with the slide holder is 2-5 mm.

In an embodiment of the invention, the thickness of the insulation sheet at the welding part of the insulation device and the slide holder can be 0.25-0.5 mm, and the thickness of the metal can be 0.25-0.5 mm.

In the embodiment of the present invention, the insulation sheet may be any material capable of achieving insulation, such as ceramic, polyimide, rubber, etc., and the metal covering the surface of the insulation sheet may be any material capable of achieving protection of the insulation material and attachment of the heat sink, such as copper, aluminum, gold, etc., and ceramic plus copper is currently preferred in view of characteristics, cost and production feasibility.

According to the process method of the internal insulation packaging structure, one surface of the wafer carrier of the copper frame is welded with the chip through welding flux, one surface of the insulation device is welded with the other surface of the wafer carrier through welding flux, the thickness of an insulation sheet of a part, which is not welded with the wafer carrier, of the insulation device is larger than that of the part, which is not welded with the wafer carrier, of the insulation device, the other surface of the insulation device is combined with the plastic packaging material, the plastic packaging material surrounds the chip, the wafer carrier and the insulation device, and metal of the part, which is not welded with the wafer carrier, of the insulation device is exposed. According to the invention, the thick edge treatment of the insulating material at the periphery of the insulating device is utilized, the strength of the insulating sheet is increased, the thermal resistance is not increased, a bottom copper frame is not required to be arranged, one-time welding process and raw materials are saved, the production cost and the material cost are reduced, the mass production is easy to realize, and only the metal part of the insulating device, which is not welded with the slide holder, is exposed during the packaging of the plastic packaging material, so that the insulation between the chip and the back radiator is realized, and the good heat dissipation between the back structure and the radiator is also realized.

In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. The meaning of "plurality" is two or more unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.