KR20060037322A - Testing of interconnections between stacked circuit boards - Google Patents

Abstract

A retainer board (25, 27, 28) having at least one hole (10) in which a wire button contact (5) is inserted, wherein the hole (10) is plated and at least one conductor (20) is connected to the plated hole for providing outside access. Moreover a method for testing stacked circuit boards are disclosed comprising the steps of detachably arranging at least two circuits boards (11, 12, 29), testing the individual functionality of the circuit boards (11, 12) and if approved, assembling the circuit boards (11, 12) and the first retainer board (25, 27, 28), and asserting whether the overall functionality of the arrangement is approved.

Description

TESTING OF INTERCONNECTIONS BETWEEN STACKED CIRCUIT BOARDS}

The present invention relates to a three-dimensional interconnect structure, and more particularly to a "z-axis" interconnect without soldering. The invention also relates to the testing of such interconnects.

Wire buttons are used in applications such as land grid array integrated circuit sockets suitable for printed circuit board (PCB) connections and parallel PCB-to-PCB interconnects. One type known as wire button is made from plated molybdenum wire and pressed into the circumferential space. Since the wire button makes a spring-force connection, the wire button can be used for a compatible connection to various devices and circuits on the test bed.

In the prior art document by SF Al-sarawi, Part B of the 21st February, 1998 issue of Part B-IEEE transaction "a review of 3D packaging technology" of devices, packaging and manufacturing techniques, a fuzz button contact contacts are used to make vertical interconnections between stacked PCBs.

International Journal of the Microelectronics and Packaging Industry, Volume 19, No. 4, 1996, the prior art document "Wire button contact retainer board for 3-D Interconnected MCMs" by REAckerman and Dean Scheafer, considerably higher packaging and interconnect density. The manufacture of a multi-chip module having a drawing is dealt with.

The document shows a test medium comprising a vertically removable stacked MCM, which is alternatively connected to the z axis by a stacked wire button contact retainer board. In FIGS. 5 and 6 on pages 458-459 of the document, a retainer substrate is shown, which includes a hard / flexible Kapton ^™ substrate 16 having wire button contact retainer substrates 14 and 16 laminated on both sides. . The laminate layer is Kapton ^TM Opposite wire buttons interconnected by through holes 9 plated in the substrate. The wire button retainer substrate is mounted vertically between each interconnect layer 7 of the stacked MCM and mounts a flexible circuit layer 20 that is connected to the test I / O device backplane.

The compression bolts retain all of the stacked structure. If the impedance of the interconnect at each terminal is not within tolerance, each affected MCM may be replaced. 1 of the present application is a schematic diagram of FIGS. 5 and 6 of that document. The button contact is conical (not shown) on the wire contact retainer substrate.

US-5619399 shows an assembly for mounting against a chip module or other circuit module. The interposer includes a rigid or flexible plate that uses an array of wire buttons through the plate, wherein when pressure is applied to the array of wire buttons, an electrical connection is made between the contacts on both sides of the plate, ie the circuit module. It is done between each contact of the phases and the substrates are arranged to be in contact with the printed wire substrate.

US-5886590 shows a microstrip orthogonal launcher to coaxial cable using a wire button center conductor as a solderless interconnect.

It is a first object of the present invention to describe a retainer substrate, which allows for accurate tolerances at the x and y levels and low structure heights in the z axis, while the signal can be accessed outward.

This object is achieved by the subject matter described in claim 1.

An additional object is to describe an apparatus for testing.

This object is achieved by claim 3.

An additional object is to describe testing methods and assemblies that can be precisely controlled.

This object is achieved by the content defined by claim 5.

Additional advantages will appear in the description of the invention below.

1 is a schematic representation of a conventional test medium employing a retainer substrate.

2, 3 and 4 show a preferred embodiment of a retainer substrate according to the invention.

5 shows a first embodiment of an apparatus for providing a probe for external testing.

6 is an exemplary device achieved according to a preferred method according to the invention.

7 is a second embodiment of an apparatus for providing a probe including a multilayer retainer substrate for external testing.

8 is a third embodiment of an apparatus for providing a probe for an external test in which two or more retainer substrates are present.

In figures 2, 3 and 4 a preferred retainer substrate 1 according to the invention is shown. The retainer substrate consists of a substrate 25 having one or more plated holes 10. One or more conductors 20 connected to the plated holes 10 are constructed on one side of the substrate. In the plated hole 10 with conical side 13 on both sides, the wire contact 5 is inserted and pressed, and fixed to the retainer substrate. The retainer substrate may be a printed circuit board (PCB). The retainer substrate may be a single layer or a multilayer substrate. Wire buttons are available from CIN :: APSE® or Tecknit®. The height of the retainer substrate as well as the physical size of the plated holes can generally be in the range of 1 mm.

In FIG. 5, an apparatus comprising two or more circuit boards 11, 12 that can accommodate many elements (not shown) is shown as interconnected by retainer substrate 25 in accordance with the present invention. Each circuit board 11, 12 comprises one or more pairs of circuit board terminals 7, which are interconnected by vertical connections suitable for the z-axis direction, such as filled vias or plated contact surfaces. The retainer substrate protrudes beyond the scope of the circuit board, whereby the I / O terminal 21 connected to the conductor 20 can be used for probe purposes.

In accordance with a preferred method of the present invention, the circuit boards 11 and 12 may be limited to test probes (not shown), physical distances between the circuit boards 11 and 12, and physical properties of the test equipment (not shown). Considering the size, they can be tested individually to the extent possible.

If the test is approved, the circuit boards 11 and 12 are assembled with the retainer substrate 25 together with the retainer substrate 25 as shown in FIG. 5 to provide a probe point of the connection defined by the retainer substrate 25. . In the test configuration, the circuit boards 11 and 12 are detachably connected by suitable clamping as is known in the art. It is concluded that the full functionality of the device has been approved.

If the entirety of the device is approved, it can be fixedly assembled. In FIG. 6, the final operating device 3 achieved by the invention is shown, in which the retainer substrate 26 functions exclusively as an interconnecting means between two or more circuit boards 11, 12. The retainer substrate 26 is clamped or glued to the circuit boards 11 and 12 to achieve a permanent connection between the circuit boards.

Thereafter, the protruding portion in contact with the outside of the retainer substrate may be cut.

Alternatively, if the entirety of the device is approved, the first retainer substrates 25, 27, 28 can be removed and the second retainer substrate 26 can be inserted. The second retainer substrate 26 is substantially the first retainer substrate (except that the retainer substrate 26 does not necessarily have conductors for contacting the outside, but also has plated holes that do not necessarily have I / O terminals). Same as 25).

Advantageously, the second retainer substrate 26 is made in the same manner as the first retainer substrates 25, 27, 28, but the parts and means in contact with the outside are omitted here.

As shown in comparison to the structure shown in FIG. 1, the number of contact surfaces to be connected between two or more circuit boards 11, 12 is reduced from four to two, providing the possibility for external signal access. Since all the contact surfaces potentially induce reflection, the high frequency properties of the connection according to the invention are enhanced compared to the prior art. Furthermore, as the connection consists of only one wire button contact instead of two according to the invention, the structure height can be at least halved. In high speed and microwave applications, performance may be proportional to the reduction in physical size.

As further seen from the above, the retainer substrate 25 for testing purposes may be made in the same manner as the final retainer substrate 26 shown in FIG. 6. Since the retainer substrates are almost identical, the performance of precise control of the final product is achieved.

According to an additional aspect of the present invention, the second retainer substrate 26 may be made from the first retainer substrate by simply cutting the protruding portion shown in FIG. 5. In this case the terminal 21 is removed, but the conductor 20 remains.

In FIG. 7, a device 4 comprising circuit boards 11 and 12 and a multilayer retainer substrate 27 are shown. The conductor 20 is electrically connected to the plated hole 10. The dielectric layer 32 constitutes the outer layer of the middle portion of the multilayer retainer substrate 27 such that the terminal 20 is electrically isolated from other wire button contacts (not shown). The I / O terminal 21 is mounted to a portion of the multilayer retainer substrate which projects through 31 beyond the range of the circuit boards 11 and 12.

An assembly of three circuit boards 11, 12, 29 and two retainer substrates 27, 28 is shown in FIG. 8.

Claims (9)

Retainer substrates 25, 27, 28 having one or more holes 10 into which the wire button contacts 5 are inserted, A retainer substrate in which the holes (10) are plated and one or more conductors (20) are connected to the plated holes for access to the outside. The method of claim 1, Retainer substrate, characterized in that the plated holes (10) are conical (13) at both ends. 1. An apparatus comprising two or more circuit boards 11, 12, 29 having a pair of opposing board terminals 7. The apparatus further comprises retainer substrates 25, 27, 28 having one or more of the plated holes 10 into which wire button contacts 5 are inserted, wherein one or more conductors 20 are connected to the wire button contacts. And wire button contacts 5 to electrically connect between the pair of opposing circuit board terminals 7 of the circuit boards 11, 12, 29 to access the outside of the circuit board. A retainer substrate, characterized in that. The method of claim 3, wherein And the retainer substrate (27,28) is a multilayer substrate and the dielectric layer (32) constitutes an outer layer of the middle portion of the multilayer retainer substrate (27,28). A method for manufacturing and testing a device that includes a stacked circuit board, Two or more circuit boards 11 having a first retainer substrate 25, 27, 28 having one or more plated holes 10 into which a pair of opposing circuit board terminals and wire button contacts 5 are inserted; 12, 19, wherein the one or more conductors 20 are connected to the plated holes to access the wire button contacts and the outside, the wire button contacts 5 being connected to the two circuits. An arrangement step of electrically connecting between said pair of opposing circuit board terminals 7 of the substrate, Testing the individual functions of the circuit boards 11 and 12 and if the test is approved, Assembling the circuit board (11, 12) and the first retainer board (25, 27, 28) and determining whether the entire function of the apparatus has been approved. The method of claim 5, On the overall approval of the device, wherein the device is fixedly assembled. The method of claim 6, And the second retainer substrate is made from the first retainer substrate (25, 27, 28) by cutting out a protruding portion that provides access out of the first substrate. The method of claim 5, On full approval, after inserting the second retainer substrate (26), the substrate is characterized in that it is substantially the same as the first retainer substrate (25, 27, 28). The method of claim 8, Formed in the same manner as the first retainer substrate (25, 27, 28), but the parts and means for providing access to the outside are omitted.

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