Integrated circuit packaging structure for solving low-temperature failure

Abstract

The utility model relates to an integrated circuit packaging structure for solving low temperature failure, comprising an integrated circuit which is provided with solder balls; a through hole is formed in the position, corresponding to the integrated circuit solder ball, of the flexible circuit board, and a PCB circuit is wound around the through hole; the flexible circuit board is provided with a plurality of through holes, one side of the flexible circuit board wound with the PCB circuit is attached and fixed to one side of the solder balls of the integrated circuit, each solder ball is at least partially accommodated in the through holes, and the flexible circuit board is electrically communicated with the integrated circuit. According to the packaging structure provided by the utility model, the appropriate flexible circuit board is arranged on the integrated circuit, the heating circuit is wound on the flexible circuit board, and devices which cannot bear low temperature on the integrated circuit are heated, so that the problem of low-temperature failure can be solved, and the power consumption of a product cannot be greatly increased. Meanwhile, according to the packaging structure provided by the utility model, a commercial chip can be applied to an industrial product, and the packaging structure can be used in a low-temperature environment.

Description

Technical Field

[0001] The utility model relates to the technical field of integrated circuits, in particular to an integrated circuit packaging structure for solving low-temperature failure. Background Art

[0002] Electronic devices and products can be found everywhere in our lives, but there are problems such as some mobile phones failing to start or shutting down automatically in winter, and surveillance cameras failing in low temperatures. In my country, the lowest temperature in the northeast, especially in the northern border, is generally -40℃ to -50℃ in winter. In such extremely cold weather, electronic products generally fail to function due to low temperatures.

[0003] At present, the main method to solve this problem in the industry is to heat the entire product so that the electronic products in the low-temperature environment can be kept in a constant temperature state higher than the ambient temperature, for example, reaching above -20°C. However, this method of heating the entire machine will greatly increase the power consumption of the overall product. Summary of the invention

[0004] In view of the lack of understanding of the above problems in the prior art, the utility model proposes an integrated circuit packaging structure that solves low-temperature failure. By heating the components on the integrated circuit that cannot withstand low temperatures, the problem of low-temperature failure can be solved without increasing the overall size of the integrated circuit or significantly increasing the power consumption of the product. At the same time, the packaging structure proposed by the utility model can apply commercial-grade chips to industrial products and can be used in low-temperature environments.

[0005] The utility model is implemented as follows: an integrated circuit packaging structure for solving low-temperature failure, comprising: an integrated circuit, the integrated circuit having solder balls; a flexible circuit board, the flexible circuit board having through holes at positions corresponding to the integrated circuit solder balls, and a PCB circuit wound around the through holes; and one side of the flexible circuit board with the PCB circuit wound is adhered and fixed to one side of the integrated circuit solder balls, each solder ball is at least partially accommodated in the through holes, and the flexible circuit board is electrically connected to the integrated circuit.

[0006] In some preferred embodiments, the length and width of the flexible circuit board are the same as those of the integrated circuit.

[0007] In some preferred embodiments, the thickness of the flexible circuit board is 0.1 mm.

[0008] In some preferred embodiments, the through hole size is the diameter p of the solder ball bump on the integrated circuit, and:

[0009]

[0010] Where p is the diameter of the solder ball bump on the integrated circuit, c is the solder ball diameter, and a is the solder ball height.

[0011] In some preferred embodiments, the through hole size is specifically:

[0012] For an integrated circuit without solder balls, the through hole diameter is 0.4 mm;

[0013] For an integrated circuit with solder balls implanted, the diameter of the through hole is 0.55 mm.

[0014] In some preferred embodiments, the through hole is a non-metallized through hole.

[0015] In some preferred embodiments, the PCB circuit is a heating copper conductor circuit, which starts from one side of the flexible circuit board, surrounds all through holes in a cross shape between two adjacent through holes, turns back on this side and leads out, or leads out on the other opposite side.

[0016] In some preferred embodiments, a layer of high temperature glue is coated on the non-opening area of ​​one side of the flexible circuit board where the PCB circuit is wound, so as to be adhered and fixed to the solder ball surface of the integrated circuit.

[0017] In some preferred embodiments, two groups of power supply pads are provided on the flexible circuit board, and the two groups of power supply pads are connected to the PCB circuit internally and to the power supply pads of the integrated circuit externally.

[0018] In some preferred embodiments, two groups of power supply pads are disposed at one corner of the flexible circuit board.

[0019] The beneficial effects of the present invention compared to the prior art are: the present invention proposes an integrated circuit packaging structure that solves the problem of low temperature failure. Specifically, at least the following beneficial effects can be obtained:

[0020] (1) The packaging structure proposed by the utility model is to set a suitable flexible circuit board on the integrated circuit and wind a heating copper conductor line on the flexible circuit board, so that the packaging structure can solve the problem of low-temperature failure of the chip at a low cost.

[0021] (2) The packaging structure proposed by the utility model is simple in design and easy to operate, does not increase the overall size of the integrated circuit, and does not significantly increase the power consumption of the product.

[0022] (3) The packaging structure proposed by the utility model can increase the low temperature range that the chip can withstand, solving the problem of using commercial-grade chips in industrial-grade products.

[0023] It should be understood that the implementation of any embodiment of the present utility model does not mean that multiple or all of the above-mentioned beneficial effects must be possessed or achieved at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the implementation of the utility model or the technical solution in the prior art, the following is a brief introduction to the drawings required for the implementation or the prior art description. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0025] The structures, proportions, sizes, etc. illustrated in this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with the technology. They are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantial technical significance. Any structural modification, change in proportion or adjustment of size shall still fall within the scope of the technical contents disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0026] Figure 1 This is a schematic cross-sectional view of an integrated circuit packaging structure according to an embodiment of the utility model;

[0027] Figure 2 This is a schematic diagram of the design of a flexible circuit board after the PCB circuit is wound according to an embodiment of the utility model;

[0028] Figure 3 This is a schematic diagram of a flexible circuit board package according to an embodiment of the utility model;

[0029] Figure 4 This is a schematic diagram of the size of solder balls on an integrated circuit according to an embodiment of the utility model;

[0030] Figure 5 This is a schematic diagram of the glue coating area of ​​the flexible circuit board according to the embodiment of the utility model;

[0031] Figure 6 This is a schematic diagram of a heating power supply circuit of a packaging structure according to an embodiment of the utility model;

[0032] Figure 7 This is a temperature variation curve diagram of a packaging structure during heating according to an embodiment of the utility model.

[0033] In the various drawings, the same or corresponding reference numerals represent the same or corresponding parts. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the utility model more clear, the utility model is further described in detail below in combination with the embodiments and drawings. Here, the illustrative embodiments of the utility model and their descriptions are used to explain the utility model, but are not intended to limit the utility model.

[0035] In the description of the present invention, the terms "include / comprise", "consist of..." or any other variants thereof are intended to cover non-exclusive inclusion, so that a product, device, process or method including a series of elements includes not only those elements, but also other elements not explicitly listed when necessary, or also includes elements inherent to such product, device, process or method. In the absence of further restrictions, the elements defined by the sentences "include / comprise...", "consist of..." do not exclude the presence of other identical elements in the product, device, process or method including the elements.

[0036] It should be understood that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.

[0037] It should also be understood that terms such as "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", and "center" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device, component or structure referred to must have a specific direction, be constructed or operate in a specific direction, and should not be understood as a limitation on the present invention.

[0038] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance, or implicitly indicating the number of technical features indicated, or limiting the order of precedence. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0039] Normally, the temperature level of commercial-grade chips is generally 0℃~70℃, which is suitable for general commercial applications, such as smart phones, tablets, TVs, etc.; the temperature level of industrial-grade chips is generally -40℃~85℃, which is suitable for industrial control, automation, communications and other fields. By analyzing the component composition of electronic products (structural components, circuit boards, electronic components, etc.), it is found that in extremely cold weather, low-temperature failure of integrated circuit chips is the main cause of functional failure of electronic products.

[0040] Based on this, the utility model proposes an integrated circuit packaging structure for solving the problem of low-temperature failure. From the perspective of chip packaging, it solves the problem of low-temperature failure of integrated circuit chips. In addition, through this structure, commercial-grade chips can be used in industrial products to meet the requirements of low-temperature environments.

[0041] See also Figure 1 As shown, the integrated circuit packaging structure is mainly composed of an integrated circuit 1 and a flexible circuit board 2.

[0042] The integrated circuit 1 is an existing integrated circuit, such as a commonly used chip. The integrated circuit 1 has solder balls 101. The integrated circuits mentioned here are divided into two types, namely, integrated circuits without solder balls and integrated circuits with solder balls. For integrated circuits with solder balls, the solder balls 101 already exist in advance. For integrated circuits without solder balls, the solder balls are implanted after the flexible circuit board 2 is attached.

[0043] The flexible circuit board 2 is selected for making this packaging structure. The flexible circuit board is a highly reliable and excellently flexible printed circuit board. It has the characteristics of high wiring density, light weight, thin thickness, and good bendability, meeting the use requirements.

[0044] See also Figure 2 A through hole 201 is provided on the flexible circuit board 2 at a position corresponding to the solder ball 101 of the integrated circuit 1, and a PCB circuit 202 is wound around the through hole 201; and one side of the flexible circuit board 2 wound with the PCB circuit is attached and fixed to one side of the solder ball of the integrated circuit 1, and each solder ball 101 is at least partially accommodated in the through hole 201, such as Figure 1 As shown, after bonding and fixing, the flexible circuit board 2 is electrically connected to the integrated circuit 1, that is, the packaging structure of the utility model is formed. During bonding and fixing, for an integrated circuit without solder balls, the flexible circuit board is bonded to the integrated circuit and fixed, and then solder balls are planted on the integrated circuit through the through holes on the circuit board; for an integrated circuit with solder balls planted, the flexible circuit board is bonded to the integrated circuit and fixed, and the solder balls pass through the through holes, such as Figure 1 shown.

[0045] The solder ball at least partially passes through the through hole, which can be Figure 1 Combined with Figure 4 It is relatively easy to understand that at least a portion of the solder ball passes through and is accommodated in the through hole, and more specifically, a portion of the solder ball having a bump diameter p is accommodated in the through hole. Figure 1 The finished state after the flexible circuit board is bonded to the integrated circuit is shown.

[0046] The utility model provides a simple structural design, does not increase the overall size of the integrated circuit, and only needs to energize the PCB circuit 202 on the flexible circuit board 2 during use, so as to heat the components of the integrated circuit 1 that cannot withstand low temperatures, thereby solving the problem of low-temperature failure of the integrated circuit.

[0047] Continue to see Figure 1 , Figure 3 The utility model selects the flexible circuit board 2 to have the same length and width as the integrated circuit 1. Figure 3 The flexible circuit board package is shown according to the integrated circuit specifications. The left side is a schematic diagram of the size of the integrated circuit 1, and the right side is a flexible circuit board 2 for making a PCB package. The PCB package is completely consistent with the integrated circuit. The thickness of the flexible circuit board selected in this embodiment is 0.1mm, and the length and width are the same as the size of the integrated circuit, both of which are 11mm*11mm. The flexible circuit board for making the PCB package already contains the pad position, and the pad position corresponds one-to-one with the solder ball 101 of the integrated circuit 1, and then through holes 201 are opened one by one at the pad position. This design can make the flexible circuit board and the integrated circuit package completely fit without increasing the overall size of the integrated circuit.

[0048] In the present invention, the size of the through hole 201 is determined by the bump diameter p of the solder ball 101 on the integrated circuit 1 and is consistent with it. Figure 4 As shown, Figure 4 In the figure, let the solder ball diameter c, solder ball height a, and p be the solder ball bump diameter on the integrated circuit. According to the chord length calculation formula:

[0049]

[0050] From the above formula, we can get:

[0051]

[0052] According to the integrated circuit specifications, the solder ball diameter c and solder ball height a are obtained, and the solder ball bump diameter p on the integrated circuit is calculated, that is, the opening size. After opening according to the above size, a through hole can accommodate or pass through at least part of a solder ball.

[0053] For example, for commonly used integrated circuits, the middle value of solder ball height a = 0.4mm, solder ball diameter c = 0.5mm, that is

[0054] According to the above calculation results, for integrated circuits without solder balls, since the solder balls are planted after the flexible circuit board is attached, the openings on the flexible circuit board can be relatively small, just enough to accommodate the area of ​​the circular solder pad bumps. Therefore, on the flexible circuit board, the opening diameter is selected to be 0.4mm. It is easy to understand that when the solder ball diameter or height is different, the calculation results of the solder ball bump diameter p are also different, so the opening size on the flexible circuit board will also change with the change of the solder ball diameter or height.

[0055] For integrated circuits with solder balls implanted, in order to ensure that the solder balls on the integrated circuit board pass through the through holes, the opening size must be at least larger than the solder ball diameter c. Therefore, for integrated circuits with solder balls implanted, in order to facilitate the fitting of the heating plate to the integrated circuit, the opening diameter is selected to be 0.55mm, which is slightly larger than the solder ball diameter c. In this way, the solder balls can smoothly pass through the through holes on the flexible circuit board.

[0056] According to the calculated opening size of the flexible circuit board, through holes are opened in advance during the process of manufacturing the flexible circuit board in the factory to facilitate its later use.

[0057] In the present invention, the through hole 201 is a non-metallized through hole, which means that the hole wall is non-metallic, no copper is exposed on the hole wall, and the hole wall has no conductive function.

[0058] In this utility model, continue to refer to Figure 2 The wound PCB circuit 202 is specifically a heating copper conductor circuit, which starts from one side of the flexible circuit board 2, surrounds all through holes 201 in a "J" shape between two adjacent through holes 201, and is turned back and led out on this side, or led out on the other opposite side. Figure 2 This wrap-around method can make the layout regular, so that the lines are evenly distributed on the entire flexible circuit board to achieve full coverage, ensuring that the integrated circuit can be completely and evenly heated.

[0059] The PCB circuit 202 uses a heating copper conductor circuit. The copper conductor circuit can be selected to surround the flexible circuit board to achieve signal connection. For example, the heating copper conductor circuit width w = 0.05mm, the cross-sectional copper thickness t = 0.017mm, and the cross-sectional area S = w*t = 0.05*0.017mm 2 .

[0060] By calculating the total length of the conductor on the board, L = 364.5 mm. From the table, we can find that the resistivity of copper is ρ = 1.7 × 10 -8 Ω·m=1.7×10 -5 Ω·mm. From this, the total resistance of the conductor on the flexible circuit board is calculated:

[0061] R = ρ*L / S = (ρ*L) / (w*t)

[0062] =(1.7*10 -5 *364.5) / (0.05*0.017)

[0063] =0.0061965 / 0.00085=7.29Ω≈7.3Ω.

[0064] The calculated resistance can be used to further calculate the heating power, thereby adopting an appropriate heating power.

[0065] In the present invention, in order to fit and fix the flexible circuit board 2 to the integrated circuit 1, as shown in FIG. Figure 5 As shown, a layer of high temperature glue is coated on the non-opening area of ​​the side of the flexible circuit board 2 wound with the PCB circuit 202, that is, the surrounding area of ​​the black round hole (i.e., the through hole 201) in the figure, and the flexible circuit board is buckled and attached to the solder ball surface of the integrated circuit, and is pressed and fixed together with the integrated circuit. This design can firmly attach the flexible circuit board to the integrated circuit without increasing the size of the integrated circuit.

[0066] In this utility model, continue to refer to Figure 2 , Figure 5 , two groups of power supply pads 203 are arranged on the flexible circuit board 2, and the two groups of power supply pads 203 are connected to the PCB circuit 202 inwardly, and are connected to the power supply pads of the integrated circuit 1 outwardly, so that the flexible circuit board 2 and the integrated circuit 1 are electrically connected as shown in the figure to achieve electrical conduction between the two. The PCB circuit 202 starts from one side and connects to a power supply pad 203, and surrounds between two adjacent through holes 201 in a "J" shape until it surrounds all through holes, and then turns back to the side to connect to another power supply pad 203. Preferably, the two groups of power supply pads 203 are arranged at one of the corners of the flexible circuit board 2, so as not to occupy too much space on the flexible circuit board 2.

[0067] Add power supply pads on the flexible circuit board. For example, when designing the flexible circuit board, two additional pads are designed, for example, at one of the corners of the flexible circuit board. The board manufacturing factory processes them according to the design documents as the starting and ending ends of the heating copper conductor line, and connects the power supply pads of the flexible circuit board to the power supply pads of the integrated circuit.

[0068] It should be noted that the integrated circuit itself has a power supply pad. When designing the integrated circuit board, it is necessary to add a power supply circuit and place temperature sensors or thermistors at the four corners of the chip to monitor the temperature T of the chip in the operating environment (the lowest temperature that the chip can withstand is T0). The specific circuit principle is as follows Figure 6 As shown, Figure 6 In the figure, J1 is the two pad pins for powering the flexible circuit board, one is VCC (power supply) and the other is GND (ground); CTRL is the control signal, and the control process is as follows:

[0069] When T≤T0+Δt, CTRL is high, the diode is turned on, and J1 starts to supply power;

[0070] When T>T0+Δt', CTRL is at a low level, the diode is closed, and J1 stops supplying power.

[0071] Δt and Δt' are set temperature margins, and different values ​​of Δt and Δt' can be set in the two cases.

[0072] Heating principle see Figure 7 , Figure 7 The temperature change curve of the integrated circuit chip is shown below. Assuming T0 = -20°C, when T reaches -20°C, the heating circuit is turned on. At this time, the ambient temperature will continue to drop, causing the chip to fail. Therefore, an adjustment parameter is added. Assuming Δt = 5°C, that is, when T ≤ -15°C, the heating is turned on. Similarly, by setting Δt, the heating can be controlled to stop when it reaches a certain temperature. It should be noted that the value of this parameter can be adjusted through the control circuit.

[0073] Assuming the supply voltage VCC = 3.3V (usual IO voltage value), the heating power of the heating plate P = U2 / R = 3.32 / 7.3 = 1.49W, and the thermal resistance Tc value of the plastic package chip is generally 10℃ / W. Therefore, under this heating power, the maximum chip temperature rise ΔT = Tc*P = 1.49*10 = 14.9℃.

[0074] In summary, the packaging structure disclosed by the utility model, through reasonable design, only needs to heat the components (chips) on the integrated circuit that cannot withstand low temperatures, which can solve the problem of low-temperature failure without increasing the overall size of the integrated circuit or significantly increasing the power consumption of the product. The overall solution is simple, easy to operate, simple in materials, and practical.

[0075] In addition, since the temperature level of commercial-grade chips is generally 0°C to 70°C, and the temperature level of industrial-grade chips is generally -40°C to 85°C, the method disclosed in the utility model solves the problem of low-temperature failure of key components on integrated circuits, so that general commercial-grade chips can withstand lower temperatures, that is, they can be used in lower temperature environments. In this way, the method and packaging structure proposed by the utility model can apply commercial-grade chips to industrial products and can be used in low-temperature environments, which broadens the application range of commercial-grade chips and increases the output value of chip manufacturers. For industrial product users, using the chip with the packaging structure proposed by the utility model can greatly reduce the cost of the product.

[0076] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

[0077] Although several specific implementation details are included in the above discussion, these should not be interpreted as limiting the scope of the present invention. Certain features described in the context of a separate embodiment may also be implemented in a single implementation in combination. On the contrary, the various features described in the context of a single implementation may also be implemented in multiple implementations individually or in any suitable sub-combination.

Claims

1. An integrated circuit packaging structure for solving low temperature failure, characterized in that: include: An integrated circuit having solder balls thereon; A flexible circuit board, wherein a through hole is provided on the flexible circuit board at a position corresponding to the solder ball of the integrated circuit, and a PCB circuit is wound around the through hole; and One side of the flexible circuit board wound with the PCB circuit is adhered and fixed to one side of the integrated circuit solder ball, each solder ball is at least partially accommodated in the through hole, and the flexible circuit board is electrically connected to the integrated circuit.

2. The integrated circuit packaging structure according to claim 1, characterized in that: The length and width of the flexible circuit board are the same as those of the integrated circuit.

3. The integrated circuit packaging structure according to claim 1, characterized in that: The thickness of the flexible circuit board is 0.1 mm.

4. The integrated circuit packaging structure according to claim 1, characterized in that: The via size is the diameter p of the solder bump on the integrated circuit, and has: Where p is the diameter of the solder ball bump on the integrated circuit, c is the solder ball diameter, and a is the solder ball height.

5. The integrated circuit packaging structure according to claim 4, characterized in that: The through hole dimensions are specifically: For an integrated circuit without solder balls, the through hole diameter is 0.4 mm; For an integrated circuit with solder balls implanted, the diameter of the through hole is 0.55 mm.

6. The integrated circuit packaging structure according to claim 1, characterized in that: The through hole is a non-metallized through hole.

7. The integrated circuit packaging structure according to claim 1, characterized in that: The PCB circuit is a heating copper conductor circuit, which starts from one side of the flexible circuit board, surrounds all through holes in a "X" shape between two adjacent through holes, turns back and leads out on this side, or leads out on the other opposite side.

8. The integrated circuit packaging structure according to claim 1, characterized in that: A layer of high temperature glue is coated on the non-opening portion of one side of the flexible circuit board around which the PCB circuit is wound, so as to be fitted and fixed to the solder ball surface of the integrated circuit.

9. The integrated circuit packaging structure according to claim 1, characterized in that: The flexible circuit board is provided with two groups of power supply pads, which are connected to the PCB circuit internally and to the power supply pads of the integrated circuit externally.

10. The integrated circuit packaging structure according to claim 9, characterized in that: Two groups of power supply pads are arranged at one corner of the flexible circuit board.

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