PROBE CARD HAVING VERTICAL TYPE NEEDLES AND THE METHOD THEREOF

Abstract: The present invention relates to a probe card for testing the failure of a semiconductor IC chip. The probe card according to the present invention comprises a vertical needle module having an upper fixing plate and a lower fixing plate through which vertical-type needles are attached; a mass ring attached to said vertical needle module for smooth contact of said vertical-type needles with pads of a semiconductor IC chip; a guide ring for smooth movement of said mass ring and said vertical needle module and for protecting said mass ring and said vertical needle module against deviation in a downward direction; a space forming means for obtaining a movement space of said mass ring, in which said means is placed above said guide ring; and a probe card PCB, on which a signal pattern is formed, formed on said space forming means, thereby protecting said upper fixing plate from movements in a lateral direction and to protect said needle module against deviations in an upper direction. The probe card can make smooth contacts between the pads formed on an upper portion of a semiconductor IC chip and the vertical-type needles and is also capable of testing a multiple of semiconductor IC chips simultaneously.

Description: PROBE CARD HAVING VERTICAL TYPE NEEDLES AND THE METHOD THEREOF FIELD OF THE INVENTION This invention relates to a probe card for testing failures of semiconductor IC chips formed onl More particularly, this invention relates to a probe card having vertical type needles which enables testing of a plurality of semiconductor IC chips simultaneously and to a method for manufacturing the same. BACKGROUND OF THE INVENTION Recently, as semiconductor IC chip manufacturing technology becomes more integrated 15and serves higher functions, the size of the IC chip has decreased. As a result, the following two testing methods have become required, in order to test failures ofthe IC chips. The first method is a wafer probing test method in which IC chips are tested in a wafer state and the second method is a final test method in which IC packages are tested after IC chips ofthe wafer state are manufactured into package-type chips. Fig. 1 shows a general wafer probing test system which can be used for the wafer probing test described above. Referring to Fig. 1, the wafer probing test apparatus comprises an IC chip test system 1 for testing IC chips in a wafer state; and an IC chip 25 test head 2 which is electrically connected to the IC chip test system 1. The wafer 4 on which a semiconductor IC chip 4A is formed is mounted on top of a chuck 6, and the chuck 6 is disposed on a wafer probe station 7. A probe card 3A shown in Fig. 2A having horizontal needles 9 is set up between the IC chip test head 2 and the wafer 4. In order to test failures of the semiconductor IC chip 4A, pads 5 formed on the semiconductor IC chip 4A are contacted with the horizontal needles 9 mounted on the probe card 3A. The probe card 3A having the horizontal needles 9 is electrically connected to the IC chip test head 2. Accordingly, the IC chip test system 1 can test for failures of the semiconductor IC chip 4A with the aid of the horizontal needles 9 mounted on the probe card 3 A which are contacted with the pads 5. A conventional probe card 3A on which the horizontal needles 9 are mounted is shown in more detail in Figs. 2 A and 2B. Generally, each ofthe horizontal needles 9 has a length in the range of 40 to 50mm and a diameter in the range of 200 to 250μm. The horizontal needles 9 are made of a conductive metal, preferably tungsten (W) , however beryllium-copper (Be-Cu) or paliney-7 (P-7) may also be used as the material for the horizontal needles 9, considering factors such as hardness, degree of wear and conductivity, etc. Also a metal plated with gold (Au) or copper (Cu) may also be used. After the horizontal needles 9 having bent tips are manufactured from one of the materials described above, a needle module is completed by forming a probe ring 10 made of an epoxy resin for fixing the horizcntal needles 9 onto the probe card 3A. Thereafter, the needle module is fixed onto a ready-made PCB of a probe card. Next, each of the horizontal needles 9 is fixed onto the signal pattern formed on the PCB by soldering. In this case, a microscope is required for working a series of processes necessary for manufacturing the needle module and fixing the horizontal needles 9 onto the PCB. Thus, it is very difficult to control the length ofthe horizontal needles 9 and to fix the positions thereof, when manufacturing the needle module. It is also difficult to control and adjust the angle of the tips of the horizontal needles 9 when bending the tips. There are other difficulties such as a lengthy process for manufacturing the probe card and high failure rate of the probe card, because it is difficult to maintain a gap between the horizontal needles when mounting the needles onto the signal pattern. Furthermore, there is another problem of frequency characteristics and impedance characteristics going bad because of the length of the needles 9. Also, controlling and adjusting the length, width and arrangement of the needles becomes more and more difficult and thus the failure rate increases because the needle module for testing a plurality of semiconductor IC chips is necessarily manufactured by depositing the needle layers in the second, third, and fourth level, etc., due to spatial limitations in manufacturing the needle module according to the size, arrangement, pitch and position ofthe pads 5, which limiteds the number of needles that can be produced. Furthermore, it is difficult to control the tension of each ofthe needles with a constant value. Accordingly, due to the problems described above, there is a design limitation when pads are arranged on the semiconductor IC chip, which ultimately leads to a limitation of performance in a multi-chip test. In Figs, 3A & 3B, another conventional probe card is shown. The structure of a membrane-type dot probe card 3 A is basically the same as that ofthe probe card having horizontal needles. However, in the membrane-type probe card 3A, portions contacting the pads 5 mounted on a semiconductor IC chip are not horizontal needles, but pointed bumps 13 which can softly contact the pads 5. In this case, the tension of the bumps 13 is maintained by a flexible membrane 12 which resultingly leads to a constant contact force being maintained between the bumps 13 and the pads 5. Also, as another supplementary unit for maintaining tension, a pressure maintaining adjustment tool 15 made of a pivot spring and a pressure-maintaining box cover 14 are formed on the membrane 12, for smoothly contacting the bumps 13 to the pads 5 and for prohibiting damage to the pads 5. Although the membrane-type dot probe card provides substantial remedies for solving many drawbacks of the conventional probe card having horizontal needles, problems remain in the membrane-type dot probe card, because the structure thereof is basically that of a horizontal type. That is, the manufacturing ofthe membrane-type dot probe card for testing a multiple of semiconductor IC chips has limitations resulting from the limitation ofthe size of the membrane for maintaining the constant tension. Additionally, there is another problem in that contact failure in some parts may occur between the bumps 13 and the pads 5, because it is difficult to control the tension of the membrane 12. Also, contact failure between a wafer and a probe card may occur because the lengths ofthe bumps 13 may be very short. SUMMARY OF THE INVENTION An object of the present invention is to provide a probe card having vertical-type needles in which a notch is formed, in order to solve the above¬ mentioned problems ofthe prior art. Another object of the present invention is to provide reliable contact between the pads and the needles. The other object of the present invention is to allow testing a plurality of semiconductor IC chips simultaneously. To accomplish the objects described above, a probe card of present invention comprises a vertical needle module where the vertical-type needles are attached to an upper and a lower fixing plates; a mass ring attached to the vertical needle module in order to smooth the contact of the vertical-type needles with pads of a semiconductor IC chip; a guide ring for smoothing the movement of said mass ring and the vertical needle module and for is prohibiting the mass ring and the vertical needle module from deviating in a downward direction; the means of forming a movable space for procuring movement space for the mass ring, the means positioned above the guide ring; and a PCB formed on an upper portion of the means of forming a movable space wherein a signal pattern is formed, the PCB functioning to protect the upper fixing plate against moving in a lateral direction and to protect the needle module against deviating in an upward direction. Also, the method of manufacturing a probe card according to the present invention comprises the steps of assembling films for an upper and a lower fixing plates; inserting vertical-type needles between the films for an upper and a lower fixing plates; forming a needle module by forming the upper and lower fixing plates which are made by injecting a thermosetting resin between the films for the upper and lower fixing plates; attaching the needle module to a mass ring and assembling the needle module to a PCB inwhich a guide ring is attached and assembling supplementary units between said mass ring and said PCB. BRIEF DESCRIPTION OF THE DRAWINGS The structure and the method of the present invention will be better understood by the following description of non-limitative embodiments, with reference to the attached drawings which are briefly described as follows: Fig. 1 is a schematic view of a general wafer probing test apparatus for performing a probing test of a IC chip. Fig. 2A is a plan view of a conventional probe card having horizontal- type needles for performing a probing test of an IC chip. Fig. 2B is a cross-sectional view of the probe card having horizontal- type needles shown in Fig. 2A. Fig. 3 A is a plan view of a conventional membrane-type dot probe card for performing a probing test of an IC chip. Fig. 3B is a cross-sectional view of the membrane-type dot probe card shown in Fig. 3A. Fig. 4A is a plan view of a probe card having vertical-type needles for performing a probing test of an IC chip according to the present invention. Fig. 4B is a cross-sectional view of an embodiment of the probe card having vertical type needles shown in Fig. 4A. Fig. 4C is a schematic view of a plurality of needles to be used for a probe card having vertical-type needles, according to the present invention. Fig. 5 is a cross-sectional view of a probe card having vertical-type needles for performing a probing test of an IC chip according to another embodiment of the present invention, where a spring controller is attached to the probe card. Fig. 6 is a cross-sectional view of a probe card having vertical-type needles for performing a probing test of an IC chip according to another embodiment of the present invention, where air or a liquid-sack buffer controller is attached to the probe card. DETAILED DESCRIPTION OF THE INVENTION Fig. 4A is a plan view of a probe card having vertical-type needles according to the present invention. A guide ring 16 is fixed to a lower portion ofthe PCB 3 where a signal pattern 11 is formed. A vertical needle module 17 shown in Fig. 4B and a mass ring 18 are arranged at inner portions of the guide ring 16. The guide ring 16 and the mass ring 18 are respectively made of a metal, such as copper, iron, aluminum, stainless steel, or of a non-metal material such as teflon, plastic, or thermosetting resin, in consideration of weight, hardness, temperature characteristics, surface frictional force, etc., thereof. Fig. 4B is a cross-sectional view of an embodiment of a probe card having vertical-type needles 19. As shown in Fig. 4B, the signal pattern 11 is formed on the PCB 3. The vertical-type needles 19 are inserted through holes formed in an upper fixing plate 20 and a lower fixing plate 20A. A circular guide ring 16 is attached, by a guide ring fixing plate 23, to the lower portion of the PCB 3. The guide ring fixing plate 23 provides space for the vertical-type needles 19 to move. The space can also be used as extra space for mounting supplementary units of the mass ring 18 in order to control the whole tension of the probe card having the vertical-type needles 19. The vertical needle module 17 is formed in a central hole portion of the PCB 3. The vertical-type needles 19 are fixed in the upper fixing plate 20 and lower fixing plate 20A ofthe vertical-type module 17 which is attached to the mass ring 18. The signal pattem 11 is connected to each of the vertical-type needles 19 by signal lines 21. The signal lines 21 are covered and protected by a closed-type cover 22. The contact between the vertical-type needles 19 and the pads 5 shown in Fig. 1 is controlled by both the weight ofthe needle module 17 including the weight ofthe mass ring 18 and minute tension ofthe vertical-type needles 19 in each of which a notch 24 shown in Fig. 4C is formed, which will be described in detail later. Fig. 4C shows a plurality of vertical-type needles 19 which are fixed to the lower fixing plate 20A. Various type of notches 24 can be formed on the vertical-type needles 19. The notches 24 are for desirable contact between the vertical-type needles 19 and the pads 5 shown in Fig. 1 by elastic force due to the bending of the vertical needles 19 themselves, in addition to a mass control method which provides control ofthe contact forces between the pads 5 shown in Fig. 1 and the vertical-type needles 19. Also, the vertical-type needles 19 have a configuration to render minute tension in order to compensate for the height tolerance which occurs when the vertical-type needles 19 are fixed to the fixing plates 20 and 20A. Accordingly, the vertical-type needles 19 themselves are able to offset the contact failure resulting from the minute height differences. That is, a probe card having vertical-type needles of the present invention uses a combination of a mass control method capable of controlling overall contact of the needles and a vertical-type needle notch method which use notches formed on each of the vertical-type needles and capable of controlling the minute height differences of the vertical-type needles. Now, the method of manufacturing the needles on which notches are formed will be described. First, holes are formed through plates and vertical type needles 19 are mounted through the holes. Thereafter, a coating film such as a photoresist is deposited onto each of the vertical-type needles 19 and the coating film is removed from a desired portion of each of the vertical-type needles 19 where notches are formed, by using a photolithographic method. Next, the plates where the vertical-type needles 19 are mounted are immersed into an etching solution. After completing the etching process of the needles 19, the remaining portions of the coating films are removed by a washing solution. Finally, the vertical-type needles 19 formed with notches are obtained by separating them from the plates. For better conductivity and soldering characteristics in the final product of the vertical-type needles 19, and for prohibiting the final products of vertical- type needles 19 from oxidation and other chemical reactions as well, the vertical-type needles 19 may be plated with nickel, chromium, copper or gold. In addition to the above method for making notches, it is also possible to make notches on the vertical-type needles 19 through precise machining or laser working. Fig. 5 shows a cross sectional view of a probe card having vertical- type needles according to another embodiment of the present invention. A spring controller is incorporated into the probe card as shown in Fig. 5. That is, by additionally installing a supplementary units of controlling spring 25 such as a plate spring or a point spring or a POGO pin, between the mass ring 18 and the upper PCB 3, the overall contact tension between the pads 5 and the vertical-type needles 19 is controlled, which enables desirable contact between the pads 5 and the vertical-type needles 19, respectively, to be made. Fig. 6 shows a probe card having vertical-type needles 19 according to another embodiment of the present invention. The overall contact tension of the probe card having vertical-type needles 19 shown in Fig. 6 is controlled by a method using a buffer 26 as an air-sack or a liquid-sack, which is incorporated into the contact pressure control method using mass ring 18 shown in Fig. 4B. Accordingly, the combination of the buffer 26 and the mass ring 18 can provide good conditions of contact between the vertical-type needles 19 and the pads 5, while the pads 5 are protected against damage, to thereby test the IC 4 shown in Fig. 1. As another altemative controlling method, a piston method which uses hydraulic pressure or atmospheric pressure may be used for controlling an overall contact tension between the pads 5 shown in Fig. 1 and the vertical- type needles 19. As described above, the probe card having vertical-type needles according to the present invention has advantages as follows: the multi-chip probe card capable of testing a plurality of chips may be manufactured easily; the positions of the pads and the needles can be freely designed because the structure of the needle module has a matrix type; and the probe card can be produced automatically and simply so that the costs of manufacturing the probe card is low, because the probe card can be manufactured by a simple method. While the particular probe card as herein disclosed and shown in detail are fully capable of obtaining their objects and advantages stated above, it is to be understood that the same is merely illustrative ofthe presently preferred embodiments of the present invention and that no limitations are intended to the details of stmcture or design or method herein shown other than described in the appended claims.

Claims: CRAIMS 1. A probe card having vertical-type needles comprising: a vertical needle module having an upper fixing plate and a lower fixing plate through which vertical-type needles are attached; a mass ring attached to said vertical needle module for smooth contact of said vertical-type needles with pads of a semiconductor IC chip; a guide ring for smooth movement of said mass ring and said vertical needle module and for protecting said mass ring and said vertical needle module against deviation in a downward direction; a space forming means for obtaining a movement space of said mass ring, in which said means is placed above said guide ring; and a probe card PCB, on which a signal pattem is formed, formed on said space forming means, thereby protecting said upper fixing plate from movements in a lateral direction and to protectsaid needle module against deviations in an upper direction. 2. The probe card having vertical-type needles according to claim 1 , wherein a notch which is contacted with a pad of said semiconductor IC chip, is formed on each of the vertical-type needles in order to have tensions for themselves. 3. The probe card having vertical-type needles according to claim 1, wherein said space forming means is positioned between said probe card PCB and said guide ring. 4. The probe card having vertical-type needles according to claim 3, wherein a means controlled by a spring is additionally positioned between said mass ring and said probe card PCB. 5. The probe card having vertical-type needles according to claim 4, wherein said means controlled by a spring is a plate spring. 6. The probe card having vertical-type needles according to claim 4, wherein said means controlled by a spring is a point spring or a POGO pin spring. 7. The probe card having vertical-type needles according to claim 1, wherein a buffer means is additionally positioned between said mass ring and said probe card PCB. 8. The probe card having vertical-type needles according to claim 7, wherein said buffer means is an air-sack buffer. 9. The probe card having vertical-type needles according to claim 7, wherein said buffer means is a liquid-sack buffer. 10. The probe card having vertical-type needles according to claim 7, wherein said buffer means is a piston for controlling an overall tension between said pads and said vertical-type needles by using a hydraulic pressure or an atmospheric pressure. 11. The probe card having vertical-type needles according to claim 1 , said probe card further comprising a closed-type cover formed on an upper portion of said probe card PCB for protecting signal lines which connect said signal pattem to each of said vertical-type needles and for controlling pressure auxiliary. 12. The probe card having vertical-type needles according to claim 1, said vertical-type needle module and said mass ring are used for controlling an overall tension between said pads and said vertical-type needles. 13. The probe card having vertical-type needles according to claim 2, said notch is used for controlling a minute tension between said pads and said vertical-type needles. 14. A method for manufacturing a probe card having vertical-type needles comprising the following steps: assembling films for an upper fixing plate and a lower fixing plate; inserting said vertical-type needles between said films for an upper fixing plate and a lower fixing plates; forming a needle module by forming said upper fixing plate and said lower fixing plate which are made by injecting a thermosetting resin between said films for said upper fixing plate and said lower fixing plates; attaching said needle module to a mass ring and assembling said needle module to a PCB inwhich a guide ring is attached; and assembling a supplementary units between said mass ring andsaid PCB.

Inventors: NAM JAE WOO, NAM, JAE, WOO
Applicants: NAM JAE WOO, NAM, JAE, WOO
Application year: 1996
Main classification: G01R1
IPC codes: G01R1, H01L21