Universal BGA256 packaging assembly

Abstract

The invention belongs to the technical field of integrated circuits, and particularly relates to a universal BGA256 packaging assembly. A tube shell is of a rectangular plate-shaped structure; a rectangular counter bore is formed in the center of the upper end face of the tube; a three-stage stepped groove is formed in the center of the rectangular counter bore; the bottommost layer of the three-stage step type groove is a chip bonding area; golden fingers are arranged on the periphery of each stage of the three-stage stepped groove, and the number of the golden fingers is N in total. The lower end face of the tube shell is provided with a metal bonding pad which is connected with an external PCB circuit. Ten layers of circuits are arranged in the ceramic tube shell, four layers are wiring layers, and copper-laid grounding protection layers are respectively arranged above and below the wiring layers; and the wiring layer connects the golden fingers with the bonding pads.

Description

Technical Field

[0001] The present invention belongs to the technical field of integrated circuits, and in particular relates to a universal BGA256 packaging component. Background Art

[0002] With the continuous advancement of integrated circuit manufacturing processes, circuit scale and the number of functional I / O (IO) components are growing. To reduce the size of the final product, the number of pins on the device package is increased, while the pin spacing is significantly reduced. However, using external lead-out chip packages like QFP can cause the package size to extend beyond the surrounding enclosure, and can lead to pin bending, deformation, and cracking during use and transportation, leading to defects and difficulties in manufacturing and repair. In theory, a universal ceramic package can be designed through a Design for Everything (DFM) approach, reducing the need for customized military chip packages, avoiding design flaws and manufacturing waste, and ultimately saving money on improving product performance and efficiency.

[0003] In recent years, with the gradual advancement of nanoscale wafer fabrication processes, packaging format and materials have become increasingly important factors limiting component performance. Ceramic packaging primarily involves technologies such as LTCC and HTCC, with materials primarily based on substrates such as Al₃O₂ and AlN. However, the overall packaging format of LTCC technology remains relatively large, hindering the development of devices with high integration and miniaturization. Furthermore, with the promotion and application of HTCC technology, an increasing number of cases are demonstrating the reliability of this material.

[0004] Therefore, HTCC-based integrated circuit packaging technology will be an important development direction for high-reliability packaging in the future. Starting from design for manufacturability (DFM), this paper proposes design requirements and methods for reference and reference in reliability simulation design technology to complete a universal ceramic BGA256 tube package design. Summary of the Invention

[0005] The purpose of the present invention is to provide a universal BGA256 package component.

[0006] The technical solution of the present invention:

[0007] A universal BGA256 package assembly, comprising a ceramic tube shell, a metal cover plate, and solder balls / solder columns;

[0008] A rectangular countersunk hole is opened at the center of the upper end surface of the ceramic tube shell; a three-step stepped groove is opened at the center of the inner cavity of the rectangular countersunk hole;

[0009] The bottom layer of the three-step groove is the bonding area; gold fingers are arranged around each level of the three-step groove, with a total of N gold fingers;

[0010] A metal pad is provided on the lower end surface of the tube shell to connect to the external PCB circuit;

[0011] The ceramic tube shell has ten layers of circuits built in, four of which are wiring layers, and copper grounding protection layers are provided above and below the wiring layers;

[0012] The wiring layer connects the gold fingers to the pads.

[0013] Preferably, the inner cavity of the rectangular countersunk hole has a depth of 0.85 mm.

[0014] Preferably, the solder pad on the lower end surface of the ceramic tube shell is connected to the external PCB circuit through a PbSn solder ball / solder column; the diameter of the solder ball / solder column is larger than the solder pad.

[0015] Preferably, the diameter of the solder ball is 0.6 mm, and the diameter of the solder pad is 0.55 mm.

[0016] Preferably, the wiring layer of the ceramic tube shell has a line width of 100um, a through hole / via hole diameter of 100um, and a hole pad diameter of 150um.

[0017] Preferably, the wiring material of the ceramic tube shell wiring layer is copper, the lead resistance R≦2.5Ω, and the insulation resistance between the leads ≥1*10 10 Ω.

[0018] Preferably, the surface metal of the metal cover plate supporting the ceramic tube shell is plated with multiple layers of nickel and gold through an electrolytic plating process, at least four layers of Ni-Au-Ni-Au.

[0019] Preferably, the ceramic shell is made of alumina.

[0020] Preferably, the ceramic shell completes structural, environmental and stress simulations, and the simulation results meet the requirements of usage conditions.

[0021] Preferably, solder balls / solder columns can be selected to suit different PCB process requirements.

[0022] Technical effects of the present invention:

[0023] 1. The ceramic tube shell in the package assembly provided by the present invention is provided with multiple steps, which can meet the transmission requirements of multiple signals at most. By transmitting signals vertically, the package size is greatly reduced while ensuring the signal transmission effect.

[0024] 2. The present invention can realize the packaging requirements of single chip to multi-chip in the inner cavity of the ceramic structure;

[0025] 3. The metal cover plate in the packaging assembly provided by the present invention adopts a multi-layer electroplating process, which greatly enhances the corrosion resistance and salt spray resistance of the device on the basis of meeting the conditions of fusion sealing welding.

[0026] 4. The present invention uses structural simulation technology to complete the structural, environmental, and stress simulation of the packaging component, supporting reliability verification before the product goes into production. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are merely exemplary, and those skilled in the art can, without inventive effort, derive other implementation drawings based on the provided drawings.

[0028] The structures, proportions, sizes, etc. illustrated in this specification are intended solely to complement the contents disclosed herein and to facilitate understanding and reading by persons skilled in the art. They are not intended to limit the conditions under which the present invention may be implemented and therefore have no substantive technical significance. Any structural modifications, changes in proportions, or adjustments in sizes, without affecting the efficacy and objectives of the present invention, shall remain within the scope of the technical contents disclosed herein.

[0029] Figure 1 This is a schematic diagram of the structural dimensions of the BGA256 tube shell component designed for the present invention.

[0030] Figure 2 A cross-sectional view of the ceramic tube shell designed for the present invention.

[0031] Figure 3 This is the internal wiring diagram of a certain layer of the ceramic tube shell designed in the present invention.

[0032] Figure 4 Simulation analysis of the junction-to-ambient thermal resistance (θJA) of the component designed for the present invention.

[0033] Figure 5 Stress simulation analysis of components designed for this invention.

[0034] Figure 6 Constant stress experimental analysis of the components designed for this invention.

[0035] In the figure: 1 is the Al2O3 ceramic shell, 2 is the sealing ring, 3 is the bonding area, 4 is the metal lead welding area, 5 is the multi-level inner cavity step, 6 is the metal cover, 7 is the chip (single or multiple), 8 is the multi-layer wiring layer, and 9 is the solder ball (or solder column). DETAILED DESCRIPTION

[0036] The following describes the implementation of the present invention using specific embodiments. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. Obviously, the embodiments described are only a portion of the present invention, not all of it. 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.

[0037] Example 1

[0038] The present invention provides a universal BGA256 package component, which can adapt to the use requirements of analog, digital and hybrid integrated circuits, and includes a ceramic tube shell, a metal cover plate, and solder balls / solder columns.

[0039] The aforementioned ceramic housing includes: an Al3O2 ceramic shell, a metal lead welding area, and an internal conductive copper wiring layer. The inner cavity height of the ceramic base reaches 0.85mm and there are three steps inside. The back of the ceramic base uses metal pads and solder balls / solder columns to realize signal transmission between the chip pad and the external PCB circuit.

[0040] As the main components of the present invention, the flatness of the multi-layer step area, sealing area, and bonding area in the ceramic cavity is 0.05mm. The back of the ceramic shell is designed to ensure the coplanarity inspection of the solder balls and the flatness is 0.08mm.

[0041] The three steps in the aforementioned ceramic shell cavity are 0.15mm high, with a total of 256 gold fingers evenly distributed on the three steps for chip PAD lead welding. The gold fingers correspond one-to-one with the solder ball array on the back of the ceramic shell through the internal wiring layer. In addition, since the internal core cavity size is sufficient, it can meet the height requirements of various packaging formats in the future.

[0042] From the perspective of electromagnetic compatibility design, the present invention has a total of 9 ceramic layers, 4 wiring layers inside the ceramic, and a total of 5 layers of electrical ground copper layers are added above and below the wiring layers for protection. The shortest signal transmission distance is ~2mm (chip PAD to ceramic tube shell solder ball), which can adapt to the chip operating frequency of 30-90MHz.

[0043] As the internal wiring of the ceramic shell, considering the design for manufacturability (DFM), the internal wiring line width is selected to be 100μm, the through hole / via aperture is selected to be 100μm, and the internal hole pad size is Φ150μm;

[0044] The above internal wiring is made of copper, the lead resistance R≦2.5Ω, the insulation resistance between leads ≥1*10 10 Ω(DC500V);

[0045] In the present invention, if the ball planting process is selected, the recommended solder ball diameter is 0.6mm, and the shell pad diameter is 0.55mm. The final minimum solder ball pull-off force and shear value are both no less than 3.5N, meeting the relevant test requirements of GJB7677.

[0046] In order to ensure the reliability of the surface metal, the present invention selects the electroplating method in the plating process;

[0047] In order to ensure the sealing reliability of the finished device of the ceramic housing, the Au80Sn20 material and the sealing welding process are selected in the design of the matching metal cover to ensure the sealing after the sealing welding.

[0048] In order to ensure the corrosion resistance of the metal cover in a salt spray environment, the metal cover plating process of the present invention selects a multi-layer nickel-gold (Ni-Au-Ni-Au) electrolytic plating method;

[0049] The present invention can meet the requirements of general ceramic packaging for multiple sizes and multiple chips: the bonding area size is 6.1mm×6.1mm, the lead length from the bonding area to the outermost gold finger is 0.35mm~2.5mm, and it can accommodate chips with a size of 4.5mm~5.1mm square;

[0050] The present invention completes the structural modeling simulation as follows Figure 1 As shown in the figure (the cover is hidden in the figure), it mainly includes a ceramic tube shell, a cover, a chip, a chip bonding layer, and a solder column. The simulation results show that the device junction-to-case thermal resistance (θ JC ) is 2.184℃ / W.

[0051] The present invention completes the structural thermal simulation, the junction temperature and the junction-to-ambient thermal resistance (θ JA ) Simulation results show that in a high-temperature environment of 125°C, when the device is installed on a 4-layer PCB, the junction temperature is 139.672°C.

[0052] The present invention completes stress simulation for the structure. When the temperature is 150℃, the thermal stress distribution of the chip is as follows: Figure 5 The maximum equivalent stress of the chip occurs at the corners of the bottom surface of the chip, with a maximum stress value of about 52.1 MPa.

[0053] In the present invention, stress simulation is completed for the structure. The maximum principal stress of the ceramic shell in a constant stress environment of 20,000g is about 13.7MPa, which appears at the bottom of the ceramic shell. This stress level is much lower than the tensile strength of the ceramic shell (150MPa). The ceramic shell meets the requirements of the 20,000g constant stress test.

Claims

1. A general BGA256 package component, characterized in that: The packaging components include: ceramic tube shell, metal cover, solder balls / solder columns; The tube shell is a rectangular plate structure; A rectangular inner cavity is opened at the center of the upper end surface of the ceramic tube shell; a three-step stepped groove is opened at the center of the inner cavity; The bottom layer of the three-step groove is the bonding area; gold fingers are arranged around each level of the three-step groove, with a total of N gold fingers; The lower end surface of the tube shell is provided with a metal pad and a solder ball which can be connected to an external PCB circuit; The ceramic tube shell has ten layers of circuits built in it, four of which are wiring layers, and copper grounding protection layers are arranged above and below the wiring layers; The wiring layer connects the gold finger to the pad; The metal cover is made of multi-layer gold-nickel plated and sealed by welding process; The back side of the package component is electrically connected to the PCB through solder balls or solder columns.

2. The packaging assembly according to claim 1, characterized in that: The depth of the rectangular countersunk hole is 0.85 mm.

3. The packaging assembly according to claim 1, characterized in that: The solder pad on the lower end surface of the ceramic tube shell is connected to an external PCB circuit through a PbSn solder ball; the diameter of the solder ball is larger than the solder pad.

4. The packaging assembly according to claim 3, characterized in that: The solder ball diameter is 0.6mm and the pad diameter is 0.55mm.

5. The packaging assembly according to claim 1, characterized in that: The wiring layer line width of the ceramic tube shell is 100um, the through hole / via aperture is 100um, and the pad diameter is 150um.

6. The packaging assembly according to claim 5, characterized in that: The wiring material of the ceramic shell wiring layer is copper, the lead resistance R≦2.5Ω, and the insulation resistance between leads ≥1*10 10 Ω.

7. The packaging assembly according to claim 1, characterized in that: The ceramic tube shell bonding area is plated with multiple layers of nickel and gold through an electrolytic plating process, at least four layers of Ni-Au-Ni-Au, and the sealing cap is in the form of fusion sealing welding.

8. The packaging assembly according to claim 1, characterized in that: The ceramic shell is made of alumina.

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