CN109655733B

CN109655733B - Method for nondestructive testing of millimeter wave BGA packaging assembly

Info

Publication number: CN109655733B
Application number: CN201811418051.0A
Authority: CN
Inventors: 刘帅; 张凯
Original assignee: Southwest Electronic Technology Institute No 10 Institute of Cetc
Current assignee: Southwest Electronic Technology Institute No 10 Institute of Cetc
Priority date: 2018-11-26
Filing date: 2018-11-26
Publication date: 2020-11-24
Anticipated expiration: 2038-11-26
Also published as: CN109655733A

Abstract

The invention discloses a method for nondestructively testing a millimeter wave BGA packaging assembly, and aims to provide a nondestructive testing method which is easy to disassemble and assemble, has high flexibility and does not have secondary damage to the tested BGA packaging assembly. The invention is realized by the following technical scheme: during testing, the metal box body (1) reversely buckles the tested BGA packaging assembly (2) on the first medium substrate (7), and a solder ball of the BGA packaging assembly (2) elastically touches the high-frequency fuzz button (5) and the low-frequency fuzz button (6); the low-frequency fuzz button (6) is in contact with the wafer of the low-frequency patch cord (14) and is communicated with a low-frequency test interface formed by the finger-shaped cord; the high-frequency signal is vertically transited to a high-impedance matching line (11) through a high-frequency fuzz button (5) and is transmitted to a standard 50-ohm universal high-frequency test interface formed by a coplanar transmission line (13) through a low-impedance matching line (12); the performance of the BGA package (2) can be tested nondestructively by the coplanar line (13) and the low frequency patch cord (14).

Description

Method for nondestructive testing of millimeter wave BGA packaging assembly

Technical Field

The invention belongs to the technical field of microwaves, and particularly relates to a method for testing the performance of a millimeter wave BGA packaging assembly.

Background

In recent years, the performance of millimeter wave devices is increasing, the cost is decreasing, and the application of millimeter waves in various fields is strongly promoted. With the improvement of millimeter wave circuit integration, Ball Grid Array (BGA) packages, which have high-density, high-frequency and low-frequency I/O interfaces and are suitable for large-scale SMT assembly processes, have been used as a mainstream packaging technology. BGA ball grid array packages are formed by fabricating array solder balls on the bottom of a package substrate as I/O terminals for electrical circuits to be interconnected with a Printed Circuit Board (PCB). The device packaged by the technology is a surface-mounted device, and can realize high-density and high-performance integration of a multi-chip Module (MCM).

And packaging a plurality of millimeter wave chips into a BGA component in a millimeter wave frequency band, and ensuring that the functional state of the component after the chips are packaged is normal before the chips are attached and welded on the PCB. Therefore, the package assembly needs to be tested first to be screened according to its performance index. If BGA encapsulation subassembly adopts the mode that the welding was assembled PCB board and is tested, take off the process of BGA encapsulation subassembly after the test is accomplished, can cause certain damage to the solder ball of BGA encapsulation. Thus, there is a pressing need for non-destructive testing of millimeter wave BGA package assemblies.

In the millimeter wave frequency band, the test socket not only needs to guarantee the low-frequency electrical communication of BGA package and PCB board, but also needs to consider the high-frequency transmission matching problem. In the conventional non-destructive testing method, springs, elastic pins, elastic silver particles, elastic silver buttons, and the like are generally used as a connection medium between the solder balls of the BGA package assembly and the microwave PCB. The spring type available frequency is low, and the spring type available frequency is difficult to be used in a millimeter wave frequency band; the elastic needle, the elastic silver particles and the elastic silver button have excellent high-frequency transmission characteristics, but have high cost and long processing period. In addition, the elastic needle is easy to damage the solder ball.

Disclosure of Invention

The invention aims to provide a nondestructive testing method which is easy to disassemble and assemble, high in flexibility, low in cost and free of secondary damage to a tested BGA packaging assembly, aiming at the defects of the existing millimeter wave BGA packaging assembly testing method.

In order to solve the technical problems, the invention is realized by the following technical scheme: a method of non-destructive testing of a millimeter wave BGA package assembly having the following features: etching a grounding copper surface 10 which is upwards corresponding to high-frequency solder balls 3 on a BGA packaging assembly 2 and a low-frequency patch wire 14 which is orthogonal to the grounding copper surface and corresponds to low-frequency solder balls 4 and is provided with a wafer finger shape on the front copper-coated surface of a second dielectric substrate 15, manufacturing a high-impedance match line 11 with a wafer and a low-impedance match line 12 which is connected with the high-impedance match line in an extending way in the long strip direction of the grounding copper surface 10, and a coplanar transmission line 13 which is connected with the terminal of the low-impedance match line 12, wherein a metalized through hole 17 is used for communicating the front grounding copper surface 10 with a large-area back grounding copper surface 16 to ensure good high-frequency grounding, etching a welding copper surface 9 which is corresponding to the grounding copper surface 10 in position and has the same shape on the back copper-coated surface of a first dielectric substrate 7, and manufacturing non-metal BGA packaging assembly 2 solder balls 8 which are; the first dielectric substrate 7 is fixedly connected with the second dielectric substrate (15) into a whole through the welding copper surface 9, and then a fuzz button serving as a vertical connecting medium for connecting the BGA packaging assembly 2 and the second dielectric substrate 15 is filled in the non-metallization through hole 8 of the first dielectric substrate 7 to form a test socket; during testing, the metal box body 1 reversely buckles the tested BGA packaging component 2 on the first medium substrate 7, and the solder balls of the BGA packaging component 2 elastically touch the fuzz buttons; the low-frequency fuzz button 6 is in contact with the wafer of the low-frequency patch cord 14 and is communicated with a low-frequency test interface formed by the finger-shaped lines; the high-frequency signal is vertically transited to a high-impedance matching line 11 through the high-frequency fuzz button 5 and is transmitted to a standard 50-ohm general high-frequency test interface formed by a coplanar transmission line 13 through a low-impedance matching line 12; thereby testing the performance of the BGA package assembly 2.

Compared with the prior art, the invention has the following beneficial effects:

simple structure improves the reliability of test. The invention adopts the fuzz buttons as the vertical transmission medium of high and low frequency signals: the high-frequency fuzz button 5 and the first dielectric substrate 7 jointly form a dielectric filling coaxial transmission line to realize high-frequency signal transmission; the single low-frequency fuzz button 6 is directly connected with each other in an elastic compression mode, and low-frequency signals are transmitted. The compression of the fuzz button can ensure that the solder balls of the BGA package 2 are in good electrical connection with the traces on the second dielectric substrate 15. And the fuzz button has small elastic contact force, and can protect a solder ball of the BGA packaging assembly from being damaged in the testing process.

Can adapt to engineering change and has high design flexibility. The invention adopts a structure that a medium substrate supports a hair button, and a high-frequency hair button 5 and a low-frequency hair button 6 are filled in a non-metalized through hole 8 of a first medium substrate 7: the low-frequency fuzz button 6 penetrates through the non-metalized through hole 8 to be in elastic contact with the wafer of the low-frequency patch cord 14 on the second medium substrate 15 to realize low-frequency electrical connection; the high-frequency fuzz button 5 penetrates through the non-metallized through hole 8, the center fuzz button is elastically connected with the wafer of the high-impedance matching line 11, and the rest fuzz buttons are elastically connected with the grounding copper surface 10. The high-frequency fuzz button 5 and the first dielectric substrate 7 form a dielectric coaxial transmission line structure, and the high-impedance matching line 11 and the low-impedance matching line 12 jointly participate in impedance matching. The material and thickness of the first dielectric substrate 7 and the sizes of the high-impedance matching line 11 and the low-impedance matching line 12 can be adjusted according to the specific requirements of the BGA packaging assembly test to optimize the high-frequency transmission performance of the application frequency band, and the flexibility of different frequency bands and bandwidth design is improved.

Low cost and short processing period. The invention is designed with low cost in multiple aspects, and the through holes of the first dielectric plate 7 are not required to be metallized, thus saving the upper copper surface circuit of the first dielectric substrate; the two single-layer dielectric substrates are fixedly connected by welding and stacking, so that a multi-layer PCB laminating process is avoided.

By adopting the test method for the separable interconnection of the millimeter wave BGA packaging assembly and the PCB, the welding process can be avoided, and the tested BGA solder balls are protected from being damaged; meanwhile, the screening, debugging and repairing work of the BGA packaging assembly is facilitated; the method can be used for the rapid nondestructive testing of the millimeter wave frequency band BGA packaging assembly.

Drawings

Fig. 1 is a schematic view of a stack-up of a method of non-destructive testing of a millimeter wave BGA package assembly of the present invention.

Fig. 2 is an exploded view of fig. 1.

Fig. 3 is a bottom exploded view of fig. 1.

In the figure: 1 metal box body, 2BGA encapsulation subassemblies, 3 high frequency solder balls, 4 low frequency solder balls, 5 high frequency fuzz buttons, 6 low frequency fuzz buttons, 7 first dielectric substrates, 8 non-metallized via holes, 9 welding copper surfaces, 10 grounding copper surfaces, 11 high impedance match lines, 12 low impedance match lines, 13 coplanar transmission lines, 14 low frequency patch lines, 15 second dielectric substrates, 16 large-area grounding copper surfaces, and 17 metallized via holes.

In order to make the object and technical solution of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

Detailed Description

See fig. 1-3. According to the invention, on the front copper-coated surface of the second dielectric substrate 15, a piece of grounding copper surface 10 which is upward corresponding to the high-frequency solder balls 3 on the BGA packaging assembly 2 and a finger-shaped low-frequency patch wire 14 which is orthogonal to the grounding copper surface and corresponds to the low-frequency solder balls 4 and is provided with a wafer are etched, a high-impedance match line 11 with a wafer, a low-impedance match line 12 which is connected with the high-impedance match line in an extending way and a coplanar transmission line 13 which is connected with the terminal of the low-impedance match line 12 are manufactured in the long strip direction of the grounding copper surface 10, the back surface of the second dielectric substrate 15 is coated with copper to form a large-area lower grounding copper surface 16, and the grounding copper surface 10 is communicated with the large-area lower grounding copper surface 16 by adopting; and etching a welding copper surface 9 with the same shape as the corresponding position of the grounding copper surface 10 on the back surface of the first dielectric substrate 7, and manufacturing non-metallization through holes 8 which correspond to the welding balls of the tested BGA packaging assembly 2 one by one. The length and width of the second dielectric substrate 15 are greater than those of the first dielectric substrate 7, so that an external test interface formed by the coplanar transmission line 13 and the low-frequency patch cord 14 is exposed after the two are fixedly connected.

Before testing, the first dielectric substrate 7 is fixedly connected with the second dielectric substrate 15 through the back welding copper surface 9; filling the high-frequency fuzz button 5 and the low-frequency fuzz button 6 into a non-metalized through hole 8 of a first medium substrate 7, wherein the high-frequency connecting fuzz button 5 penetrates through the non-metalized through hole 8, the central fuzz button is elastically connected with a wafer of a high-impedance matching line 11, and the rest fuzz buttons are elastically connected with a grounding copper surface 10; the low-frequency fuzz button 6 penetrates through the non-metallized through hole 8 to be elastically connected with the linear array wafer on the low-frequency patch cord 14, so that the test socket which is fixedly connected into a whole is formed.

During testing, the metal box body 1 enables the tested BGA packaging assembly 2 to be reversely buckled and fixedly connected on the first medium substrate 7, so that the solder balls of the BGA packaging assembly 2 and the fuzz buttons are elastically touched; the low-frequency fuzz button 6 is upwards elastically touched with the low-frequency solder ball 4 of the BGA packaging assembly and downwards contacted with the linear array wafer of the low-frequency patch cord 14 to form a low-frequency communicated test interface; the high-frequency signal on the high-frequency solder ball 3 of the BGA packaging assembly 2 is vertically transited through the high-frequency fuzz button 5, and is transmitted to a standard 50-ohm general high-frequency test interface formed by a coplanar transmission line 13 through a high-impedance matching line 11 and a low-impedance matching line 12; finally, the typical test socket structure with the low frequency patch cord 14 and the coplanar transmission line 13 as shown in fig. 1 is formed to enable non-destructive testing of the performance of the millimeter wave BGA package assembly.

After the test is finished, the tested BGA packaging assembly 2 can be directly detached; the test socket is reusable.

When the BGA packaging component is used, the position and the size of the through hole of the first dielectric substrate 7 can be changed according to the application requirements of different distribution forms of the solder balls of the BGA packaging component; meanwhile, based on the working frequency band of the tested BGA package assembly 2, the material and thickness of the first dielectric substrate 7 and the dimensions of the high-impedance match line 11 and the low-impedance match line 12 are flexibly adjusted to perform high-frequency impedance matching design. In a specific working frequency band, good transmission of high-frequency signals can be realized through simulation design.

The present invention is further illustrated in detail by the specific examples described above. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not limited to the ball distribution pattern of the BGA package assembly and the number of test interfaces for high and low frequencies.

Claims

1. A method of non-destructive testing of a millimeter wave BGA package assembly having the following features: forming non-metallized through holes (8) corresponding to solder balls of a tested BGA packaging assembly (2) on a first dielectric substrate (7), etching a grounding copper surface (10) which corresponds to high-frequency solder balls (3) on the BGA packaging assembly (2) upwards and a low-frequency patch wire (14) which is orthogonal to the grounding copper surface and corresponds to low-frequency solder balls (4) and is provided with a wafer finger shape on a front copper-coated surface of a second dielectric substrate (15), and forming a high-impedance match line (11) with a wafer, a low-impedance match line (12) which is connected with the high-impedance match line in an extending mode and a coplanar transmission line (13) which is connected with the terminal of the low-impedance match line (12) on a long-strip copper surface of the grounding copper surface (10); then, the first dielectric substrate (7) and the second dielectric substrate (15) are fixedly connected into a whole in a stacking mode, and the high-frequency fuzz buttons (5) and the low-frequency fuzz buttons (6) which are used as vertical connecting media for connecting the BGA packaging assembly (2) and the second dielectric substrate (15) are filled in the non-metalized through holes (8) of the first dielectric substrate (7) to form an electrical communication structure which elastically touches up and down to form a test socket; during testing, the metal box body (1) reversely buckles the tested BGA packaging assembly (2) on the first medium substrate (7), and the solder balls of the BGA packaging assembly (2) elastically touch the fuzz buttons; the low-frequency fuzz button (6) is in contact with the wafer of the low-frequency patch cord (14) and is communicated with a low-frequency test interface formed by the finger-shaped cord; the high-frequency signal is vertically transited to a high-impedance matching line (11) through a high-frequency fuzz button (5), and is transmitted to a standard 50-ohm universal high-frequency testing interface formed by a coplanar transmission line (13) through a low-impedance matching line (12), so that the performance of the BGA packaging assembly (2) is subjected to nondestructive testing.

2. The method of non-destructive testing of a millimeter wave BGA package assembly of claim 1, wherein: in the fuzz button, a high-frequency fuzz button (5) and a first medium substrate (7) form a medium coaxial line and elastically touch a high-impedance matching line (11).

3. The method of non-destructive testing of a millimeter wave BGA package assembly of claim 1, wherein: the wafer reaches and realizes high frequency electrical connection around ground connection copper face (10) to high frequency fuzz button (5) have upwards elastically touched high frequency solder ball (3) on BGA encapsulation subassembly (2), and elasticity contact high impedance match line (11) down communicates coplane transmission line (13) along low impedance match line (12), constitute BGA encapsulation subassembly (2) and transmit the external test interface of high frequency signal.

4. The method of non-destructive testing of a millimeter wave BGA package assembly of claim 1, wherein: the low-frequency fuzz button (6) upwards elastically touches a low-frequency solder ball (4) on the BGA packaging assembly (2), and downwards elastically contacts a linear array wafer on a low-frequency patch cord (14), so that a low-frequency signal is transmitted along the low-frequency patch cord (14), and an external test interface for transmitting the low-frequency signal by the BGA packaging assembly (2) is formed.

5. The method of non-destructive testing of a millimeter wave BGA package assembly of claim 1, wherein: before testing, the high-frequency fuzz buttons (5) are filled in the non-metalized through holes (8) of the first medium substrate (7), the high-frequency connection fuzz buttons (5) penetrate through the non-metalized through holes (8), the center fuzz buttons are elastically connected with the circular piece of the high-impedance matching line (11), and the rest fuzz buttons are elastically connected with the grounding copper surface (10).

6. The method of non-destructive testing of a millimeter wave BGA package assembly of claim 1, wherein: the length and width of the second dielectric substrate (15) are larger than those of the first dielectric substrate (7).

7. The method of non-destructive testing of a millimeter wave BGA package assembly of claim 1, wherein: the first dielectric substrate (7) is used for fixedly connecting the etched bottom copper-coated surface of the first dielectric substrate with the etched bottom copper-coated surface of the second dielectric substrate (15), and the etched bottom copper-coated surface of the first dielectric substrate is corresponding to the etched bottom copper-coated surface of the second dielectric substrate (7) and is a welding copper surface (9) with the same shape as the etched bottom copper-coated surface of the first dielectric.

8. The method of non-destructive testing of a millimeter wave BGA package assembly of claim 1, wherein: the bottom surface of the second dielectric substrate (15) is coated with a copper surface grounding copper surface (16), and the grounding copper surface (10) is communicated with the large-area lower grounding copper surface (16) through the metalized through hole (17), so that a good high-frequency grounding effect is ensured.

9. The method of non-destructive testing of a millimeter wave BGA package assembly of claim 1, wherein: the first dielectric substrate (7) and the second dielectric substrate (15) form a fixedly-connected test socket through welding.