JP2000314745A - Probe tip constitution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system and method for probing a pad array of high density while restraining a probe load on an objective array. SOLUTION: This constitution is a probe tip constitution including a pad 103 positioned in a high density pad array to minimize a pad load in the high density pad array, and a probe tip resistor 106 having a first and second end parts 109, 113 out of which the first end part 109 is connected to a pad. The resistor 106 is arranged to be adjacent directly in the vicinity of the pad as allowed in production as possible. The probe tip constitution includes also an access transmission line 123 connected to the second end part 113 of the probe tip resistor 106 and extended outside the high density pad array.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates generally to systems and methods for probing high density pad arrays, and more particularly, for probing high density pad arrays while reducing probe loading on a target array. Systems and methods.

[0002]

2. Description of the Related Art Integrated circuits, such as processors and other similar devices, are becoming increasingly faster and the number of operations performed per second is increasing. These integrated circuits are often provided on printed circuit boards or other similar structures, which are in electrical communication with many different electrical components and other integrated circuits on the same printed circuit board. To facilitate communication between the integrated circuit and several other electronic components,
Integrated circuits typically include a plurality of pins arranged in a high density grid or array that are inserted into corresponding high density array sockets or holes in a printed circuit board.

[0003] In many cases, such new integrated circuits need to be tested after manufacture to test prototypes or to diagnose problems encountered in the integrated circuit. Specifically, it is common to probe one or more pins in an array to access the signals thereon and transmit the signals to a logic analyzer, oscilloscope or other diagnostic device. It is difficult to perform such tests on integrated circuits that operate at high frequencies because the pins of the integrated circuits are arranged in a high-density array.

[0004] To further illustrate, a typical printed circuit board has a ground plane and a plurality of conductors that pass randomly between various components on the board. When a conductor makes contact with a representative pad located in a high-density array into which the pins of an integrated circuit are inserted, a very small capacitance, on the order of picofarads or less, exists between the pin and either a ground plane or random conductor May cause specific impedance. At low frequencies, this impedance is very high. However, at very high signal frequencies, e.g., on the order of hundreds of megahertz, the impedance created by such capacitances is low, thereby making unnecessary or extraneous loading on the circuits in the integrated circuit driving the pins. ) Will occur.

[0005] This unwanted load can cause signal distortion on the pin and cause errors in the data represented by the signal on that pin. As a result, the use of the probe itself impairs the test capability of the integrated circuit.

[0006]

As described above, it is an object of the present invention to provide a system and method for probing a high-density pad array while suppressing the probe load on the target array.

[0007]

SUMMARY OF THE INVENTION The present invention provides a system and method for probing a high density pad array while reducing probe loading on the target array. In one embodiment, a pad located in the high density pad array and a probe tip having first and second ends are provided to minimize pad loading in the high density pad array.
A probe configuration is provided, wherein the probe has a first end coupled to a pad. The probe tip resistor is located as close to the pad as possible and directly adjacent to the pad for manufacturing. The probe tip configuration further includes an access transmission line coupled to the second end of the probe tip resistor and extending out of the high density pad array. The access transmission line can be coupled to an electrical connector leading to a logic analyzer, oscilloscope or other diagnostic device to test signals on each pad in the pad array.

The present invention also provides a method for probing pads in a high density pad array. In this sense, a broad overview of the method is provided: the first end of the probe tip resistor is placed on one pad of the high density pad array, such that the probe tip resistor is directly adjacent to the pad. Placing an access transmission line coupled to the second end of the probe tip resistor and extending out of the high density pad array; coupling an external analyzer to the access transmission line; and Analyzing the signal obtained from the pad using an external analysis device.

The present invention has numerous advantages, some of which are described below by way of example only. For example, the use of probe tip resistors prevents inadvertent loading of circuits in the integrated circuit that drive each pad by isolating the pads from the probe circuit. Furthermore, the present invention has a simple structure, is user-friendly, has a reliable processing, is reliable and efficient, and can be easily mass-produced for commercial use.

[0010] Other features and advantages of the present invention will become apparent to one with skill in the art upon examination of the following description and figures. The scope of the present invention is intended to include all such additional features and advantages. Note that a deeper understanding of the present invention can be obtained by referring to the drawings described below. The elements in the figures are not necessarily drawn to size relative to each other, but are drawn with an emphasis on clearly illustrating the principles of the invention. Further, corresponding elements are denoted by the same reference numerals throughout the several drawings.

[0011]

DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. 1A, a top view of a high density pad array 100 according to one embodiment of the present invention is shown. The high-density pad array 100 includes a grid of pads 103, which are conductive holes extending through a printed circuit board 104 or other similar planar surface member. Pad 103 is typically adapted to receive pins of an integrated circuit or other electronic device. The high density pad array 100 further includes a plurality of probe tip resistors 106 having a first end 109 and a second end 113. First end 109 of each probe tip resistor 106
Are electrically coupled to the respective pads 103,
A predetermined coupling length 11 between the first end 109 of the probe tip resistor 106 and the pad 103, respectively.
6 are formed. Predetermined bond length 116
Is as short as possible so that the probe tip resistor 106 is directly adjacent to the pad 103, and is typically as short as manufacturing permits. The second end 113 of the probe tip resistor 106 is connected to the printed circuit board 1.
Via 119 that provides a conductive path through hole 04
Electrically coupled to

Referring to FIG. 1B, a high-density pad array 10 is shown.
0 is shown in the bottom view. Vias 119 extend through printed circuit board 104. The high-density pad array 100 further includes a plurality of transmission lines 123a, 123b, 12
3c, 123d and 123e. Transmission lines 123a-
123e is from via 119 to high density pad array 10
0 and extends to the end point 139. End point 1
At 39, connect the transmission lines 123a-123e to a logic analyzer, oscilloscope or other diagnostic device (not shown).
It can be electrically connected to a connector for coupling to. Although the transmission lines 123a-123e are shown as exiting from the high density pad array 100 in a uniform fashion,
The transmission lines 123a-123e may follow any path and exit the high density pad array 100 in any convenient direction for various considerations. For example, transmission lines 123a to 123a to limit interference at high frequencies
It is desirable to keep the length of the high-density pad array 100e as short as possible, or due to manufacturing constraints.
The actual route out of may be determined. Further, the arrangement of the pads 103 may restrict the path of the specific pads 103 from the high-density pad array 100.

Referring to FIG. 2, a probe system 2 includes a high density pad array 210 having a plurality of pads 103.
00 is shown. The high density pad array 210 also includes a plurality of probe tip resistors having a first end 109 and a second end 113. The first end of each probe tip resistor 106 is electrically coupled to a respective pad 103 with a coupling length 116 that is as short as manufactureable as described above in connection with FIG.

Second end 1 of probe tip resistor 106
13 is a transmission line 123f, 123g, 123h, 123i.
And 123j. Transmission lines 123f to 123
j exits the high density pad array 210 from the second end 113 of the probe tip resistor 106 and exits the electrical connector 229.
Alternatively, it is coupled to another circuit (not shown). The electrical connector 229 is electrically connected to the logic analyzer 233 by a cable 236. It should be noted that an oscilloscope may be used instead of the logic analyzer 233.

The function of the high density pad arrays 100 and 210 will be described below with reference to FIGS. An integrated circuit, such as a processor, includes a plurality of pins that are typically inserted into each pad 103 of pad array 100,210. In general, pads 103 also electrically connect to other integrated circuits and various components on printed circuit board 104. The signals generated by the integrated circuits attached to the pad arrays 100, 210 are transmitted to other components on the printed circuit board 104 while the entire circuit on the printed circuit board 104 is operating. However, the pad arrays 100 and 210 are not limited to the pad arrays 100 and 210, but include ball grid arrays, pin grid arrays, via arrays on printed circuit boards, and printed circuits to which the principles described herein can be applied. It should be noted that conductors on a substrate, conductor arrays on multi-chip modules or other similar types of packages, etc. are also included.

Probe tip resistor 106 and transmission line 12
3a-123e and 123f-123j access signals on pads 103 in the high density pad array,
It is used to test the operation of the integrated circuit attached to the high density pad array 100, 210. Specifically, the signal transmitted from the integrated circuit through the pad 103 includes the probe tip resistor 106 and the transmission lines 123 a to 123 a.
Also transmitted to the logic analyzer 233 or other similar diagnostic devices via 23e, 123f-123j. By providing the first end 109 of the probe tip resistor as close as possible to the pad 103, the transmission line 123
A load on the pad 106 that can occur when the probe tip resistor 106 that couples a to 123e and 123f to 123j to the respective pads 103 in the high-density pad array 210 is not used can be avoided. This will be further described.

Transmission lines 123a-123e and 123f-
When 123j is directly coupled to pad 106, transmission lines 123a-123e and 123f-123j add extra capacitance to pad 106. Specifically, the transmission lines 123a to 123e and 123f to 123
A capacitance of j is formed between the transmission lines 123a-123e and 123f-123j and any ground plane (not shown) or other conductive path on the printed circuit board 104. At relatively low frequencies, the effect of this capacitance on the signal is insignificant. However, transmission lines 123a-123e and 123f-
As the frequency of the signal on 123j increases, transmission line 1
The impedance caused by the capacitances of 23a-123e and 123f-123j approaches zero. Thus, for example, at very high frequencies, typically on the order of hundreds of megahertz, the transmission lines 123a-123e and 12
3f-123j tend to load the integrated circuit that drives pad 103 to which its transmission lines 123a-123e and 123f-123j couple. Such a load on the pad 103 causes a signal generated by the integrated circuit to be distorted, and the data represented by the signal may be distorted to such an extent that the signal cannot be recognized.

The probe tip resistor 106 is, for example, about 72
Although it has a resistance of 0 ohm, other resistances may be used depending on the application. For example, in many applications the resistance is 200
To 1000 ohms, but may be larger or smaller than this range depending on the particular application. The actual resistance of the probe tip resistor is selected taking into account several factors. For example, if the probe tip resistance is too high, the amplitude of the signal received by the logic analyzer will be uselessly small. Conversely, if the resistance value is too low, the probe 103 will have a load effect on the pad 103 that the probe tip resistor 106 seeks to minimize.

The actual size of the probe tip resistor 106 depends on the size of the high density pad array 210.
For example, the pads 103 may be arranged at a predetermined pitch defined by the distance from the center of each pad 103 to the center. For example, the accompanying probe tip resistor 106
Has a length of 0.201 mm or 0.402 mm (0.02 inch or 0.04 inch) and a pitch of 1 mm (0.02 inch or 0.04 inch).
5 inches). High density pad array 2
10 pitch and associated probe tip resistor 1
The size of 06 varies depending on the application, and can be made as small as possible in manufacturing.

Referring to FIG. 3, there is shown an interposed high density pad array 300 in which pads 103 and resistors 106 are arranged in an interleaved pattern. Intercalated high density pad array 300 illustrates another example of how pads 103 and probe tip resistors 106 can be arranged to form a high density pad array. In fact, any particular arrangement, or pattern, may be used by a particular application.

Referring now to FIG. 4, a pogo pick off using a high density pad array 360 provided on a printed circuit board 363 according to another embodiment of the present invention.
-off) A side view of the device 350 is depicted. The high density pad array 360 includes a plurality of pads 366 arranged in a predetermined pattern as described above. Each pad 366 is electrically coupled to a resistor 369, which is electrically coupled to a pickoff point 373. The pogo pick-off device 350 further includes a pin mounting block 376 to which a plurality of pogo pins 379 are mounted. The pogo pins 379 are electrically coupled to a logic analyzer, oscilloscope or other diagnostic device (not shown). The integrated circuit 383 is a printed circuit board 363.
Is inserted into the high-density pad array 360 from above.

When the pogo pick-off device 350 operates, each pogo pin 379 will have its own pick-off point 373.
To access the signal on each pad 366. Note that the pogo pins 379 provide signal paths from the printed circuit board 363 for transmission lines 123a-123e and 123f-123j.
(FIGS. 1B and 2) does not exist. The signal is transmitted to a logic analyzer or an oscilloscope through the pogo pin 379 and analyzed. In general, the pogo pick-off device 350 can be employed when there is sufficient clearance on the bottom side of the printed circuit board 363 to allow the pogo pins 379 and the respective pick-off points 373 to be fitted.

Referring now to FIG. 5, a socket 4 including a high density pad array 210 according to another embodiment of the present invention.
10 shows a side view of a socket probe device 400 utilizing the same. Socket probe apparatus 400 includes an integrated circuit 383 with pins 416 inserted into pads 419 of socket 410, and pads 419 collectively form high density pad array 210 on socket 410. Socket 410 includes socket pins 429 that are inserted into an array of holes in printed circuit board 423, which are electrically coupled to other components or the like on printed circuit board 423. It should be noted that in the case of a ball grid array or the like, the pins 416 become solder balls.

Each pad 41 of the high-density pad array 210
9 couples to respective ends of the probe tip resistor 426. The coupling length between the probe tip resistor 426 and the pad 419 is as short as possible for manufacturing, as described above in connection with FIGS. 1A and 2. Probe tip resistor 41
The other end of 6 is routed out of the dense pad array 210 by a transmission line (not shown) as described above in connection with FIGS. 1B and 2 and leads to a termination point. The transmission line electrically couples the probe tip resistor 426 through the collector to the logic analyzer as described in connection with FIG. Thus, socket 410 may be used to operate integrated circuit pins 416 for purposes of testing the functionality of the integrated circuit.
It is used between the integrated circuit and the printed circuit board to gain access to the above signals.

FIG. 6 is a side view of a conductive elastomer pick-off probe device (or a pick-off probe device using a conductive elastomer) 450 according to still another embodiment of the present invention. The conductive elastomer pick-off device 450 includes a printed circuit board 453 having a plurality of conductive holes 456 for receiving pins 416 of an integrated circuit 383 inserted on the printed circuit board 453.
On the bottom of the printed circuit board 453, Thomas &
MPI ConnectorSystem from Betts
There is a conductive elastomeric pickoff board 459 such as em ™. The conductive elastomer pickoff board 459 includes a plurality of conductive elastomer contacts 463 arranged in a pattern that matches the pattern of the holes 456 in the printed circuit board 453. The conductive elastomer pickoff board 459 is constructed of a flexible material so that each of the conductive elastomer contacts 463 can be electrically coupled to a corresponding hole 453 on the circuit board. The conductive elastomer contact 463 is ductile to easily deform and conform to the contour of the hole 453. Underneath the conductive elastomeric pickoff board 459 is a circuit board 46 including the high density pad array 210 described in connection with FIG.
There are six.

The conductive elastomer pick-off probe device 450 operates as follows. The integrated circuit 383 is
It drives digital signals on pins 416 that are transmitted to other components on printed circuit board 453. The digital signal also travels through conductive elastomer contacts 463 to circuit board 466. The high density pad array 210 is used to send digital signals to a logic analyzer or oscilloscope as described above.

Finally, FIG. 7 shows a conductive elastomer interposer including an integrated circuit 383 inserted into the printed circuit board 453 described above in connection with FIG.
r: interposer) device 500 is shown. The conductive elastomer interposer device 500 further includes a conductive elastomer interposer 503 having a plurality of conductive elastomer contacts 463. On the bottom surface of the conductive elastomer interposer 503, there is a high-density pad array 210,
The conductive elastomer contact 463 is the pad 103 (FIG. 2)
Plays a role. Accordingly, the conductive elastomer interposer 500 operates similarly to the conductive elastomer pick-off device 450 without the circuit board 466.

Many variations and modifications can be made to the embodiments of the invention described above without departing significantly from the spirit and principles of the invention. The scope of the present invention is intended to include all such modifications and variations.

The embodiments of the present invention have been described in detail above. Hereinafter, examples of each embodiment of the present invention will be described.

(Embodiment 1) A high-density pad array (10
0) A probe tip configuration for minimizing pad loading during, wherein a pad (103) located in the high density pad array (100) and a first end coupled to the pad (103). (109), and the pad (10)
Probe tip resistor (106) directly adjacent to 3)
And a second end (113) of the probe tip resistor (106), and the high-density pad array (10
0) The probe tip configuration including an access transmission line (123) extending outside.

(Embodiment 2) The coupling length (1) between the probe tip resistor (106) and the pad (103)
16) is the pad (1) in the high-density pad array.
3. The probe tip configuration according to claim 1, wherein the distance between the probe tip and the pad (103) adjacent to the probe tip is smaller than that of the probe tip.

(Embodiment 3) The access transmission line (12
3. The probe tip configuration according to embodiment 2, wherein 3) terminates in a connector (229) for obtaining coupling to an external analyzer (233).

(Embodiment 4) A high-density pad array (10) configured to obtain a connection to an integrated circuit (383)
0), each having a first end (109) coupled to a pad (103) in the high density pad array (100), directly adjacent to each of the pads (103). A probe tip resistor (106), each coupled to a second end (113) of one of the probe tip resistors (106), the high density pad array (10
A) a plurality of access transmission lines (123) extending out of 0).

(Embodiment 5) The coupling length between each of the probe tip resistors (106) and each of the pads (103) is equal to the respective pads (103) in the high-density pad array (100). 5. The socket according to claim 4, wherein the distance is smaller than the distance between the pad and the adjacent pad (103).

(Embodiment 6) The access transmission line (12)
The socket according to claim 5, wherein 3) terminates in a connector (229) to obtain a connection to an external analyzer (233).

Embodiment 7 A high-density pad array (100) configured to obtain a bond to a target pad array on a circuit board (453), and each pad in the high-density pad array (100). (103) having a first end (109) coupled to each said pad (10).
The probe tip resistor (10) directly adjacent to 3)
6) and a plurality of access transmission lines (1) each coupled to a second end (113) of the probe tip resistor (106) and extending out of the high density pad array (100).
23).

(Embodiment 8) The respective coupling length (116) between the probe tip resistor (106) and the pad (103) is different from the respective pad (103) in the pad array (100). The interposer of claim 7 wherein the distance is less than a distance between the pad and an adjacent pad (103).

(Embodiment 9) The access transmission line (12)
The interposer according to embodiment 8, wherein 3) terminates in a connector (229) to obtain a connection to an external analysis device (233).

[0039]

As described above, the present invention can provide a system and a method for probing a high-density pad array while suppressing the probe load on the target array.

[Brief description of the drawings]

FIG. 1A is a top view of a high density pad array according to one embodiment of the present invention.

FIG. 1B is a bottom view of the high density pad array of FIG. 1A.

FIG. 2 is a block diagram of a probe device according to another embodiment of the present invention.

FIG. 3 is a diagram of an interposed high-density pad array according to another embodiment of the present invention.

FIG. 4 is a side view of a pogo pick-off device using a high-density pad array according to another embodiment of the present invention.

FIG. 5 is a side view of a socket probe device using the high-density pad array of FIG. 2;

FIG. 6 is a side view of a conductive elastomer pick-off probe device using the high-density pad array of FIG. 2;

FIG. 7 is a side view of a conductive elastomer interposer device using the high-density pad array of FIG. 2;

[Explanation of symbols]

 100: High density pad array 103: Pad 106: Probe tip resistor 109: First end of probe tip resistor 113: Second end of probe tip resistor 116: Between probe tip resistor and pad Connection length 123: access transmission line 229: connector 233: external analyzer 453: circuit board

 ──────────────────────────────────────────────────続 き Continued on the front page (71) Applicant 399117121 395 Page Mill Road Palo Alto, California U.S.A. S. A. (72) Inventor Kenneth W. Johnson Johnson, Colorado Springs, Colorado United States Marlstone Place 825

Claims (1)

[Claims] 1. A probe tip configuration for minimizing a pad load in a high-density pad array, comprising: a pad located in the high-density pad array; and a first end coupled to the pad. A probe tip resistor directly adjacent to the pad; and an access transmission line coupled to a second end of the probe tip resistor and extending out of the high density pad array. Constitution.