A lead frame structure design method

Abstract

The present invention discloses a lead frame structure design method, comprising the following steps: simulating an adjustable lead frame based on parameters of a lead frame to be designed, the parameters including necessary parameters and optional parameters; obtaining a temperature field of the adjustable lead frame using thermal simulation analysis, and obtaining extreme points of the temperature field; adjusting the optional parameters of the adjustable lead frame based on the extreme points; wherein, during the thermal simulation analysis, the thermal simulation analysis results are adjusted based on the anti-corrosion structure in the optional parameters, taking into account the corrosion of the adjustable lead frame during the electroplating process of the electroplating area, the corrosion of the lead frame by the solution on the non-electroplating area and / or the carrier. The present invention not only incorporates the heat dissipation effect brought by the anti-corrosion structure itself into the thermal simulation analysis, but also incorporates the corrosion results that may be caused by the anti-corrosion structure into the thermal simulation analysis results, making the thermal simulation analysis more accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor electronic component manufacturing, and in particular to a lead frame structure design method. Background Art

[0002] As the chip carrier of integrated circuits, the lead frame is a key structural component that uses bonding materials (gold wire, aluminum wire, copper wire) to achieve electrical connection between the chip's internal circuit leads and external leads, forming an electrical circuit. It acts as a bridge to connect with external wires. Lead frames are required in most semiconductor integrated circuits and are an important basic material in the electronic information industry. To improve the efficiency of automated production, lead frames are generally composed of multiple identical copper-based units arranged together. Each copper-based unit includes a heat sink, a carrier, and internal and external leads that are sequentially connected into one. The carrier is used to carry the chip of the electronic component. The chip is encapsulated in a plastic package and sealed on the carrier.

[0003] In the prior art, thermal simulation analysis is usually used when analyzing lead frames or integrated circuits. For example, the invention patent with application number CN201910929147.1 discloses a test method for simulating the heating power and surface temperature of a chip, which is implemented in the following steps: under ambient temperature conditions, the relationship between the surface temperature T of the actual chip sample under operating conditions and time τ is tested, and the T-τ curve of the actual chip operating temperature and time, the Ph-τ curve of the surface temperature and the chip internal heating power Ph and the time τ are obtained, and the relationship curve Pv-T-τ between the electric power Pv and the simulated chip surface temperature T and time τ is obtained. A heat transfer model with the same size as the actual chip and its heat transfer mathematical model are established to obtain the relationship between the chip thermal power Ph and the simulated chip electric power Pv; connect a DC power supply and a programmable controller, power on and heat the simulated chip, load the actual operating program, control the voltage output of the programmable control module, test and simulate the chip surface temperature, compare the measured surface temperature of the simulated chip with the actual chip surface temperature, and simulate the heating power of the actual chip.

[0004] This existing technology takes into account the chip structure in a general sense. However, for the production of the lead frame as a chip carrier, the semiconductor lead frame needs to be injected with chemicals for corrosion treatment during the tin plating process of the heat sink and the carrier. However, during the tin plating process, the chemicals may leak to other places of the heat sink and the carrier that do not require electroplating, which will have a certain impact on the product. Therefore, in order to reduce the impact of corrosion, an anti-corrosion structure is designed on the lead frame.

[0005] However, if the thermal simulation analysis of the lead frame with the anti-corrosion structure is carried out using the method of the prior art as described above, only the heat dissipation effect brought about by the shape of the anti-corrosion structure itself is taken into consideration (for example, the heat dissipation brought about by the increased area of the slots or recessed holes), and the anti-corrosion effect of the anti-corrosion structure is not taken into consideration, that is, the corrosion effect on the lead frame itself will cause the material of the non-electroplated area on the carrier / heat sink of the lead frame to undergo chemical changes, thereby causing the problem of inaccurate thermal analysis. Summary of the Invention

[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for designing a lead frame structure.

[0007] The object of the present invention is achieved through the following technical solutions:

[0008] A first aspect of the present invention provides a lead frame structure design method, comprising the following steps:

[0009] Simulating an adjustable lead frame according to parameters of the lead frame to be designed, wherein the parameters include necessary parameters and optional parameters;

[0010] The temperature field of the adjustable lead frame is obtained by thermal simulation analysis, and the extreme points of the temperature field are obtained;

[0011] adjusting optional parameters of the adjustable lead frame according to the extreme value point;

[0012] Among them, during the thermal simulation analysis, according to the anti-corrosion structure in the optional parameters, the thermal simulation analysis results are adjusted by considering the corrosion of the adjustable lead frame during the electroplating process of the electroplating area and the corrosion of the lead frame's non-electroplating area and / or the carrier by the solution.

[0013] Furthermore, the lead frame includes a heat sink, and the heat sink includes an electroplating area, a non-electroplating area, and a first anti-corrosion structure located between the electroplating area and the non-electroplating area.

[0014] Furthermore, the first anti-corrosion structure includes a dovetail groove and / or a vertical groove.

[0015] Furthermore, the lead frame includes a carrier, and a second anti-corrosion structure is provided on a side step of the carrier.

[0016] Furthermore, the second anti-corrosion structure is a multi-row pitting structure.

[0017] Furthermore, the necessary parameters are parameters required by the customer, and the optional parameters are a part of all parameters of the lead frame excluding the necessary parameters.

[0018] Furthermore, the necessary parameters include lead pin shape and size; the optional parameters include anti-corrosion structure, device layout structure, and material, shape and thickness of non-essential devices.

[0019] Furthermore, the thermal simulation analysis results are adjusted based on the anti-corrosion structure in the optional parameters, taking into account the corrosion of the adjustable lead frame during the electroplating process of the electroplating area and the corrosion of the lead frame's non-electroplating area and / or the carrier by the chemical solution, specifically including:

[0020] Obtain parameters of anti-corrosion structures, including type, quantity and thickness;

[0021] determining an anti-corrosion effect of the anti-corrosion structure on the adjustable lead frame;

[0022] Adjust the thermal simulation analysis results based on the corrosion protection results.

[0023] Furthermore, the judging of the anti-corrosion effect of the anti-corrosion structure on the adjustable lead frame specifically includes: judging based on historical experimental data, or judging based on a judgment model formed by historical experimental data.

[0024] Furthermore, the adjusting of the thermal simulation analysis results specifically includes: increasing or decreasing the temperature of the temperature field corresponding to the corrosion position according to the corrosion ratio of the anti-corrosion result.

[0025] The beneficial effects of the present invention are:

[0026] (1) In an exemplary embodiment of the present invention, not only the heat dissipation effect of the anti-corrosion structure itself is incorporated into the thermal simulation analysis, but also the corrosion results that may be caused by the anti-corrosion structure are incorporated into the thermal simulation analysis results, making the thermal simulation analysis more accurate. The consideration of adopting this method is mainly because the corrosion effect on the lead frame itself will cause the material of the non-electroplated area on the carrier / heat sink of the lead frame to undergo chemical changes, and the analysis process will not include this data judgment, thereby causing the problem of inaccurate thermal analysis.

[0027] (2) In another exemplary embodiment of the present invention, the heat sink is an important part of the thermal simulation analysis, and mainly includes a plating area, a non-plating area, and a first anti-corrosion structure located between the plating area and the non-plating area. The plating area is usually electroplated with tin, and since the non-plating area is connected to the plating area, it is necessary to avoid plating the non-plating area as much as possible during the plating process, otherwise it will affect the performance or appearance of the product.

[0028] (3) In another exemplary embodiment of the present invention, the carrier is also easily corroded during the electroplating process, so a second anti-corrosion structure is provided on the side steps thereof.

[0029] (4) In another exemplary embodiment of the present invention, the required parameters are the parameters required by the customer, and the optional parameters are a portion of all the parameters of the lead frame excluding the required parameters. The customer / manufacturer may have certain restrictions on the lead frame to be produced, so these parameters are not adjusted in subsequent adjustments, and the remaining parameters are adjustable optional parameters.

[0030] (5) In another exemplary embodiment of the present invention, the thermal simulation analysis results are adjusted accordingly based on the corrosion resistance of the corrosion-resistant structure. Although the most preferred corrosion-resistant structure is definitely completely corrosion-resistant, due to the different necessary parameters of different customers, it is inevitable that some corrosion will occur in some cases, so this situation needs to be considered separately.

[0031] (6) In another exemplary embodiment of the present invention, the temperature of the temperature field corresponding to the corrosion position is increased or decreased mainly based on the adjustment of temperature parameters caused by the area after corrosion and the chemical changes of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The present invention is a flowchart of a method provided in an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0033] The technical solution of the present invention is described clearly and completely below with reference to the accompanying drawings. It is apparent that the embodiments described are only a portion of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are intended to fall within the scope of protection of the present invention.

[0034] In the description of the present invention, it should be noted that the directions or positional relationships indicated by terms such as "center," "up," "down," "left," "right," "vertical," "horizontal," "inside," and "outside" are based on the directions or positional relationships described in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, terms such as "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0035] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention.

[0036] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0037] See also Figure 1 , Figure 1 A lead frame structure design method provided in an exemplary embodiment of the present invention is shown, comprising the following steps:

[0038] S01: simulating an adjustable lead frame according to parameters of a lead frame to be designed, wherein the parameters include necessary parameters and optional parameters;

[0039] S03: Utilize thermal simulation analysis to obtain the temperature field of the adjustable lead frame and obtain the extreme value points of the temperature field;

[0040] S05: adjusting optional parameters of the adjustable lead frame according to the extreme value point;

[0041] Among them, during the thermal simulation analysis, according to the anti-corrosion structure in the optional parameters, the thermal simulation analysis results are adjusted by considering the corrosion of the adjustable lead frame during the electroplating process of the electroplating area and the corrosion of the lead frame's non-electroplating area and / or the carrier by the solution.

[0042] Specifically, in this exemplary embodiment, not only the heat dissipation effect brought by the anti-corrosion structure itself is incorporated into the thermal simulation analysis, but also the corrosion results that may be produced by the anti-corrosion structure are incorporated into the thermal simulation analysis results, making the thermal simulation analysis more accurate.

[0043] The reason for adopting this method is that the corrosion of the lead frame itself will cause chemical changes in the material of the non-electroplated area on the lead frame carrier / heat sink, and the analysis process will not have this data judgment, thus resulting in inaccurate thermal analysis.

[0044] More preferably, in an exemplary embodiment, the lead frame includes a heat sink, and the heat sink includes a plated area, a non-plated area, and a first corrosion protection structure located between the plated area and the non-plated area.

[0045] Specifically, in this exemplary embodiment, the heat sink, a key component of the thermal simulation analysis, primarily includes a plated area, a non-plated area, and a first anti-corrosion structure located between the two areas. The plated area is typically tin-plated, and since the non-plated area is connected to the plated area, it is important to minimize plating on the non-plated area during the electroplating process, as this would affect product performance or appearance. Therefore, the first anti-corrosion structure is located between the plated and non-plated areas.

[0046] More preferably, in an exemplary embodiment, the first anti-corrosion structure includes a dovetail groove and / or a vertical groove.

[0047] Specifically, in this exemplary embodiment, the functions of the dovetail groove and the vertical groove are to prevent the corrosion solution from leaking into the dovetail groove and the vertical groove when the lead frame is electroplated in the electroplating area. This will prevent the corrosion solution from leaking into the dovetail groove and the vertical groove due to the barb structure of the dovetail groove and the groove body structure of the vertical groove, thereby preventing the solution from leaking and corroding.

[0048] More preferably, in an exemplary embodiment, the lead frame includes a carrier, and a second anti-corrosion structure is provided on a side step of the carrier.

[0049] Specifically, in this exemplary embodiment, the lead frame further includes a carrier sheet, which is also easily corroded during the electroplating process, and therefore a second anti-corrosion structure is provided on the side steps thereof.

[0050] More preferably, in an exemplary embodiment, the second anti-corrosion structure is a multi-row pitting structure.

[0051] Among them, the pitting structure can effectively prevent the lead frame from leaking into the carrier during the tin electroplating process and corroding the carrier.

[0052] More preferably, in an exemplary embodiment, the necessary parameters are parameters required by a customer, and the optional parameters are a portion of all parameters of the lead frame excluding the necessary parameters.

[0053] Specifically, in this exemplary embodiment, the customer / manufacturer may impose certain restrictions on the lead frame to be produced, so this content will not be adjusted in subsequent adjustments, and the remaining parts are adjustable optional parameters.

[0054] More preferably, in an exemplary embodiment, the necessary parameters include lead pin shape and size; the optional parameters include anti-corrosion structure, device layout structure, and material, shape and thickness of non-essential devices.

[0055] More preferably, in an exemplary embodiment, the thermal simulation analysis results are adjusted based on the anti-corrosion structure in the optional parameters, taking into account corrosion of the adjustable lead frame by the solution on the non-electroplating area and / or the carrier during the electroplating process of the electroplating area, specifically including:

[0056] Obtain parameters of anti-corrosion structures, including type, quantity and thickness;

[0057] determining an anti-corrosion effect of the anti-corrosion structure on the adjustable lead frame;

[0058] Adjust the thermal simulation analysis results based on the corrosion protection results.

[0059] Specifically, in this exemplary embodiment, the thermal simulation analysis results are adjusted accordingly based on the corrosion resistance of the corrosion-resistant structure. Although the most preferred corrosion-resistant structure is definitely completely corrosion-resistant, due to the different required parameters of different customers, some corrosion is inevitable in some cases, so individual considerations are required for these situations.

[0060] More preferably, in an exemplary embodiment, the determining the corrosion protection effect of the anti-corrosion structure on the adjustable lead frame specifically includes: determining based on historical experimental data, or determining based on a determination model formed based on historical experimental data.

[0061] The historical experimental data may be a plurality of experimental data produced on site, and the judgment model may be a neural network or other type of model.

[0062] More preferably, in an exemplary embodiment, adjusting the thermal simulation analysis results specifically includes: increasing or decreasing the temperature of the temperature field corresponding to the corrosion position according to the corrosion ratio of the anti-corrosion result.

[0063] Specifically, in this exemplary embodiment, the temperature of the temperature field corresponding to the corrosion position is adjusted upward or downward mainly based on the area after corrosion, the temperature parameters caused by the chemical changes in the material, etc.

[0064] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications can be made based on the above descriptions. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications derived therefrom remain within the scope of protection of the present invention.

Claims

1. A lead frame structure design method, characterized by: The following steps are involved: Simulating an adjustable lead frame according to parameters of the lead frame to be designed, wherein the parameters include necessary parameters and optional parameters; The temperature field of the adjustable lead frame is obtained by thermal simulation analysis, and the extreme points of the temperature field are obtained; adjusting optional parameters of the adjustable lead frame according to the extreme value point; The lead frame includes a heat sink, and the heat sink includes an electroplating area and a non-electroplating area; the lead frame includes a carrier; The optional parameters include anti-corrosion structure; During the thermal simulation analysis, the thermal simulation analysis results are adjusted based on the anti-corrosion structure in the optional parameters, taking into account the corrosion of the adjustable lead frame during the electroplating process of the electroplating area and the corrosion of the lead frame's non-electroplating area and / or the carrier by the chemical solution; The corrosion effect on the lead frame itself will cause chemical changes in the material of the non-electroplated area on the lead frame carrier and / or heat sink. Not only the heat dissipation effect brought by the corrosion-resistant structure itself is incorporated into the thermal simulation analysis, but also the corrosion results that may be caused by the corrosion-resistant structure are incorporated into the thermal simulation analysis results. According to the anti-corrosion structure in the optional parameters, the thermal simulation analysis results are adjusted taking into account the corrosion of the adjustable lead frame during the electroplating process of the electroplating area and the corrosion of the lead frame's non-electroplating area and / or the carrier by the solution, specifically including: Obtain parameters of anti-corrosion structures, including type, quantity and thickness; determining an anti-corrosion effect of the anti-corrosion structure on the adjustable lead frame; Adjusting thermal simulation analysis results according to the anti-corrosion results; The adjusting of the thermal simulation analysis results specifically includes: increasing or decreasing the temperature of the temperature field corresponding to the corrosion position according to the corrosion ratio of the anti-corrosion result.

2. A lead frame structure design method according to claim 1, characterized in that: The anti-corrosion structure includes a first anti-corrosion structure located between the electroplating area and the non-electroplating area on the heat sink.

3. A lead frame structure design method according to claim 2, characterized in that: The first anti-corrosion structure includes a dovetail groove and / or a vertical groove.

4. The lead frame structure design method according to claim 1, wherein: The anti-corrosion structure includes a second anti-corrosion structure provided on a side step of the carrier.

5. The lead frame structure design method according to claim 4, wherein: The second anti-corrosion structure is a multi-row pitting structure.

6. The lead frame structure design method according to claim 1, wherein: The necessary parameters are parameters required by the customer, and the optional parameters are a part of all parameters of the lead frame excluding the necessary parameters.

7. A lead frame structure design method according to claim 1 or 6, characterized in that: The necessary parameters include the shape and size of the lead pins; the optional parameters also include the device layout structure, and the material, shape and thickness of non-essential devices.

8. The lead frame structure design method according to claim 1, wherein: The determining of the corrosion protection effect of the anti-corrosion structure on the adjustable lead frame specifically includes: determining based on historical experimental data, or determining based on a determination model formed based on historical experimental data.

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