JP2005283569A - Vertical type probe card - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vertical probe card using a ceramic plate which performs a previous process test of an IC fired on a wafer. <P>SOLUTION: The probe card is characterized by a coaxial jumper cable connector, connecting the ceramic plate arranged with a pin connector which is opposite to the IC and a wiring substrate made of resin connected to a tester. The pin connector is arranged in a through-hole, formed into a matrix form on the ceramic plate to which metal coating is applied to the surface wall of the through-hole. The ceramic plate is connected electrically to a connecting terminal which is arranged, with an expanded spacing in the spacing between the through-holes via the wiring circuit formed in an interior or a surface of the ceramic plate. Moreover, the probe card is constituted of the ceramic plate arranged with a pin connector opposite to the IC fired on the wafer, an ICU made of the resin having connector spacing, corresponding to the expanded connector spacing of the ceramic substrate and the wiring substrate made of the resin connected to the tester. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vertical probe card used for a pre-process test of an integrated circuit.

A large number of integrated circuits (hereinafter abbreviated as ICs) are burned on a wafer, tested using a probe card (pre-process test), and only non-defective products are taken out and placed in a case and packaged into a product. Even after becoming a product, a socket is attached to the performance board for testing (post-process test or product test).
In a pre-process test in which the quality of an IC is tested at the stage where the IC is burned onto a wafer, a probe card incorporating a probe composed of a cantilever lever or the like has generally been used (see Patent Document 1).

As shown in FIG. 7, the probe card disclosed in Patent Document 1 makes the tip of the probe 33 abut against the bump 32 of the IC chip 31 and conducts to the wiring pattern 35 of the substrate 34 via the probe 33. Thus, the distance between the electrodes arranged finely and densely on the IC chip 32 is greatly expanded at the tip of the wiring pattern 35 (opposite the contact point of the wiring pattern 35 with the probe 33), and a tester (not shown) ) And a substrate can be connected to the board without any particular difficulty.
ICs have recently been used in large quantities everywhere. Therefore, a large amount of probe cards has been required. However, in order to arrange and fix the cantilever levers according to the arrangement of the bumps, the cantilever levers are manually arranged under the microscope, so it is difficult to mass-produce and the cantilever levers are multi-staged. Will require more manual work.
Furthermore, the current electrode gap (pitch) in the cantilever lever system is compatible with ICs that tend to be further miniaturized and densified due to restrictions such as the thickness and thickness of the probe. It is considered that 60 μm is the limit.
Also, a hard metal probe such as a tungsten alloy often damages the bumps.

In the case of a product IC, the bump interval can be expanded larger than the electrode interval (pitch) of the IC when it is housed in the case (for example, a pitch on the order of mm such as a 1.27 mm pitch is usually used). Therefore, in the case of a post-process test, a needle (see Patent Document 2) or a performance board for a test socket using a pin contact is used instead of the probe.
As shown in FIG. 8, the vertical probe card disclosed in Patent Document 2 is slidable on the electrode 42 on the surface of the wafer 41 to be inspected in the coupling hole 44 provided in the support plate 43 made of an insulator such as plastic. Through the inserted needle 45, it is electrically connected to the connection electrode 47 of the wiring substrate 46, and is arranged on the wafer 41 to be inspected by reaching the electrode 49 with the through hole or via hole and the internal wiring pattern 48. When the connection between the performance board and the tester is further increased from the performance board (not shown), the connection between the wiring board 46 and the general-purpose connection structure that does not cause any particular difficulty can be adopted. Has been made.

In order to form the coupling hole 44 in the support plate 43 made of an insulating material such as plastic or the reinforcing plate made of glass epoxy plate, it is customary to perform punching or cutting. Similar to the above-described probe card for the previous process, there has been a restriction that the pitch is almost limited to 0.6 mm (600 μm). If it was impossible, a prototype corresponding to a pitch of 0.4 mm (400 μm) could be produced, but this resulted in a problem with the strength of the probe card substrate.
Also in the case of pin contacts, until recently, there were dimensional constraints similar to those in the case of needles, both in terms of the distance between the through holes and in terms of constraints on the size of the pin contact itself.

  In Patent Document 2, it is said that a material having a low coefficient of thermal expansion, such as ceramic or Invar alloy, may be used in order to cope with high temperature measurement / testing. However, in that case, in order to protect the needle contact end and to secure an insulating layer, an insulating coating such as a resin must be applied to the inner surface of the coupling hole (guide hole) in which the needle contact end slides. For this reason, the guide hole diameter of the support plate material itself is twice as large as that of the coating layer, and it is said that there is a problem that the hole pitch cannot be reduced correspondingly and the increase in the number of pins cannot be achieved. Further, it has been said that the conventional glass epoxy substrate connected to the tester and the ceramic socket cannot be connected as they are because the materials are too different.

JP-A-6-118100 Japanese Patent Laid-Open No. 2001-21584

  An object of the present invention is to provide a vertical probe card using a ceramic plate for pre-testing an IC burned on a wafer.

The vertical probe card for the pre-process test of the present invention has a coaxial structure in which a ceramic plate provided with pin contacts that contact an IC burned on a wafer and a synthetic resin wiring board connected to a tester are coaxial. It is connected with a jumper cable connector.
The pin contact is disposed in a through-hole formed in a matrix and provided with a metal film on a peripheral wall of the ceramic plate, and the ceramic plate is disposed inside or on the surface of the ceramic plate. It is preferable that each of the through holes is electrically connected to the connection terminals arranged at an extended interval through the formed wiring circuit.
When more importance is placed on mass productivity, a ceramic plate provided with pin contacts for contact with an IC burned on a wafer, and a resin-made resin having a contact interval corresponding to the enlarged contact interval of the ceramic substrate. It is comprised by ICU and the wiring board made from a synthetic resin connected to a tester.

  According to the present invention, the punching of the ceramic sheet at the green sheet stage can be easily realized with a small hole diameter using a punch, and the pin contact that can cope with the higher density of the bumps of the IC is provided. A laminated ceramic plate having through holes to be inserted / fixed can be obtained. Then, by performing necessary wiring or the like on each layer of the laminated ceramic plate, it is possible to form a ceramic substrate having a contact interval in which the interval between the bumps of the IC is enlarged. In a mode in which a coaxial jumper cable connector is used to connect a ceramic substrate and a glass epoxy substrate connected to a tester, the specification of the IC to be tested can be changed quickly and easily by inserting and fixing the pin contact of the coaxial jumper cable connector. Compared to the conventional one, it is possible to realize a probe card that is much better. Further, when the connection form using the ICU is used instead of the connection using the coaxial jumper cable connector, mass production of the dedicated type probe card is possible, although the above-mentioned versatility is sacrificed.

  In the present invention, a pin contact of a probe card that directly contacts an electrode of an IC (represented by a bump) is held by a ceramic laminate, and a conventional glass epoxy substrate and a ceramic that are conventionally connected to a tester. The fact that a socket made of metal is so different in material that it cannot be connected as it is is based on the fact that it is possible to connect different materials with a coaxial jumper cable connector. In addition, when using a coaxial jumper cable connector, there is a merit that it is possible to easily cope with differences in IC types and wiring, but the arrangement of the coaxial jumper cable connector relies on humans, and mass production of probe cards It may not always be satisfactory in terms of sex. In that case, ICU is used instead of the jumper cable, and the versatility of the probe card is sacrificed, but mass production can be achieved as a dedicated probe card for each IC.

When an IC is used in various and large quantities, the IC cannot be used as a product unless the performance of the IC is manufactured as designed and tested to operate as designed. This is why it is desired that a large number of probe cards for testing ICs in the previous process are easily supplied at low cost.
The present invention remarkably improves the inefficiency, which is a drawback of the conventional cantilever type probe card, by using a ceramic laminate.
That is, according to the present invention, a ceramic plate (for example, glass ceramic), for example, in the stage of a green sheet having a thickness of 0.1 mm, a thin plate is finely penetrated by poking at the tip of a needle (not a drill, but a punch). The hole can be easily formed, and by forming a metal film (preferably copper or gold) on at least the peripheral wall of the through-hole, conduction between the front and back surfaces can be ensured. Based on knowledge.

The present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is an explanatory plan view showing the entire vertical probe card of the present invention. FIG. 2 is an explanatory side view of the vertical probe card of the present invention. FIG. 3 is an explanatory view showing an example of a pin contact suitably used in the vertical probe card of the present invention, in which (a) is a partially cutaway side view and (b) is an enlarged side view.
1 and 2, reference numeral 1 denotes a ceramic socket in which a grid-like pin contact group that contacts an electrode of an IC chip is provided at the center. On the surface (upper in FIG. 2) side of the socket, pin contact connection terminals of each grid-like pin contact group contacting the electrodes of the IC chip are exposed. On the back side of the socket, socket connection terminals corresponding to each pin contact of the pin contact group are displayed on the outer periphery of the grid-like pin contact group at an extended interval compared to the grid-like pin contact group. I'm out.

One group of grid-like pin contact groups can be provided at the center of the socket, and an appropriate number of plural groups may be provided if desired. When a plurality of groups are provided, it is not always necessary to be adjacent to each other, and a desired repetitive pattern can be formed.
The socket 1 is placed on the ceramic substrate 2. A socket connection terminal corresponding to the socket connection terminal of the socket 1 is exposed on the center side of the ceramic substrate 2, and a ceramic substrate connection terminal electrically connected to each socket connection terminal on the back side of the outer portion. Is appearing. The ceramic substrate connection terminal has a through-hole shape.

The ceramic substrate 2 is placed on a wiring substrate 3 made of a glass epoxy substrate or the like. The wiring board 3 is formed with a through hole 4 having a diameter smaller than that of the ceramic substrate 2 in the center, and a ceramic substrate connection terminal is formed in the overlapping portion (overlapping portion) 5 between the wiring substrate 3 and the ceramic substrate 2. A wiring board connection terminal connected to the performance board is formed on the outside thereof.
The ceramic substrate connection terminal provided on the ceramic substrate 2 and the ceramic substrate connection terminal provided on the wiring substrate 3 are electrically connected by a detachable coaxial jumper cable 6.
The coaxial jumper cable connector is preferably 50Ω impedance matched.

For example, a ceramic substrate is formed by punching through holes having a diameter of, for example, 60 μm in a grid pattern using a punch on a ceramic green sheet having an appropriate composition having a thickness of 0.1 mm. An appropriate metal, preferably copper or gold, is formed on at least the inside of the through-hole using an appropriate means such as a vapor deposition technique. In addition, an extended contact pattern is formed. Since the contact pitch of the extended contact pattern can be arranged so as not to be a critical interval, it can be appropriately formed by a usual formation method.
A desired wiring pattern can also be formed on the ceramic green sheet. When the wiring pattern is formed, a contact (socket connection terminal) that can be connected to the outside is formed at each tip portion by a through hole or a via hole.

A required number of ceramic green sheets that are perforated and have a metal film formed on the inside of the through hole are prepared and stacked to be integrated.
When the internal wiring pattern is not formed at the stage of the ceramic green sheet, it is desirable to have contacts (socket connection terminals) that can be connected to the outside on the (outer) surfaces of the outermost layer of the integrated ceramic socket. A wiring pattern is formed.
Manufacturing a ceramic compact with a fine structure is expensive, so usually a relatively small socket is formed, using a method that does not present a particularly difficult problem in terms of manufacturing technology. The ceramic substrate is manufactured with specifications that do not require exceptional strictness, and the two are joined together. However, it is not prohibited to have both a socket and a ceramic substrate, and the latter case is also included in the technical scope of the present invention.

A pin contact is attached to the through hole of the ceramic socket having a metal coating on the inner wall surface and integrated with the through hole being aligned.
The pin contact is brought into contact with each electrode of the IC at a required pressure, and the electrical connection between the electrode of the IC and the metal film on the wall surface of the through hole of the socket is ensured.
As an example of the pin contact, as shown in FIG. 3, a spring 8 is mounted inside the tube 7, and plungers 9 are arranged at both ends of the spring 8.
The tip of the plunger 9 may be a cone or a sphere, but it is also preferable that the tip of the truncated cone has a shape in which a plurality of diameters are cut or a hollow cylinder. FIG. 3B shows an example of a pin contact having a hollow portion 10 at the center.

If at least the plunger is made of a highly conductive metal such as a gold alloy instead of plating, it always keeps a fresh surface (contact) by scraping the solder contamination that adheres to the tip of the pin contact with the solder bump with a file. End) is more preferable.
The pin contact is preferably detachable from the through hole of the socket. If it can be attached and detached using a jig, the pin contact can be reused a plurality of times, and there is an advantage that the specification of the IC can be changed, a setting error can be corrected, and the like.
The ceramic socket and the ceramic substrate are joined by an appropriate method. The combination of the ceramic socket and the ceramic substrate allows the IC chip fine and dense contact electrode arrangement to be expanded and rearranged on the ceramic substrate and connected to a tester, for example, made of glass epoxy substrate It becomes easy to connect to the connection wiring board.

However, the direct electrical connection between the ceramic substrate and the glass epoxy substrate is not generally performed since the materials are too different.
One of the major features of the present invention is that electrical connection between the ceramic substrate and the glass epoxy substrate is performed using a coaxial jumper cable (connector) having pin terminals at both ends. The coaxial jumper cable is provided by Japan IF Co., Ltd. under the trademark “CJP”.

It is not always necessary to attach pin contacts to all of the through holes formed in the socket. Even in a conventional probe card made of a glass epoxy substrate, for example, when there are about 1000 bump electrodes of an IC chip in one IC, the number of electrode positions actually used for inspection is one of them. An example that was actually used only about 20% is that it is commonly seen.
In reality, the number of bumps that can be tested is several hundreds or less.
There are various IC circuit patterns depending on the purpose. Depending on their specifications, the position of the bump to be actually tested can often vary.

Assuming this, the following aspects can be considered for the matrix of through holes formed in the required portion of the socket.
One is a mode in which through holes are formed in all the required areas at the shortest pitch, and pin contacts are inserted only into desired through holes based on the specifications of the IC to be tested. In this case, a single socket can cope with various types of IC specifications, and is suitable for a pre-process test of IC specifications that are not manufactured in such a large amount. When pin contacts can be attached and detached, it is particularly versatile.
Another mode is a mode in which a through hole is formed only at a position on a socket that is optimal for an IC specification to be mass-produced, and the socket is used exclusively for a pre-process test of the IC.
Needless to say, the probe card of the present invention can be adapted to any of these modes.

The probe card for IC pre-process test has been described above, but it can also be used as a product performance board for post-process test by adjusting the pin contact pitch. In other words, it is possible to appropriately form the through-hole having a larger pitch and a larger diameter.
However, it is usually not considered a good idea to make a product made of expensive ceramics that can be realized even by using a cheaper synthetic resin substrate.

[Demonstration Experiment 1]
The pin contact shape shown in FIG. 3 is a hollow type plunger pin contact with a tube diameter of 150 μm and a plunger diameter of 101 μm, and is punched on a ceramic green sheet with a pitch of 0.2 mm ( A ceramic substrate having 79 × 79 = 6241 bumps formed on a 200 μm through-hole matrix was produced.
Of the through-holes in the socket, including the adjacent through-holes, 512 through-holes were selected in a desired pattern, pin contacts were attached, and 50Ω impedance matching was performed with the glass epoxy board shown in FIGS. A pre-process test was performed using an IC specially made for confirmation by connecting with a coaxial jumper cable, and the necessary test results were obtained.

When the production quantity of ICs to be manufactured is relatively small, typically in the case of high-mix low-volume production, the probe card of the type described so far is used for the production speed or the change of IC type / wiring. It can be well adapted to the re-arrangement speed of coaxial jumper cables.
However, some ICs of one type / wiring need to secure a 6-digit or 7-digit quantity per month. In the case of such an IC, it is necessary to concentrate a considerable amount of production on the probe card used for the pre-process test. In such a case, even at the expense of versatility (even as a dedicated machine), it is necessary to give priority to increasing the production speed.

To that end, it is conceivable to reform the arrangement of coaxial jumper cables that depend on manpower.
In the above-mentioned combination of IC chip (-test head) -ceramic substrate-coaxial jumper cable-glass epoxy substrate-tester, the contact interval from the ceramic substrate to the glass epoxy substrate is increased. Instead of expanding the contact interval by an inter connecting unit), the combination of IC chip (-test head) -ceramic substrate-ICU-glass epoxy substrate-tester was realized.
The probe card of the type using the coaxial jumper cable has a restriction on the high frequency characteristics. However, the connection with the ICU of the present invention makes it possible to test the operating characteristics in a higher high frequency region.

FIG. 4 is a cross-sectional explanatory view of a vertical probe card using an ICU according to the second embodiment of the present invention. FIG. 5 is a cross-sectional explanatory view of a vertical probe card using an ICU according to the second embodiment of the present invention. FIG. 6 is an explanatory view of the surface of the ICU showing an example in which a pre-process test is simultaneously performed on four IC chips with the vertical probe card using the ICU according to the second embodiment of the present invention.
In FIG. 4, 11 is a test head, 12 is a ceramic substrate, 13 is an ICU, 14 is a wiring substrate (made of glass epoxy), and these are assembled by stiffeners 15 and 16.

An IC chip (device) (not shown) is arranged on the front surface (right side of FIG. 5) of the test head 11 and used for a pre-process test.
The ceramic substrate 12 has the same basic configuration and structure as the ceramic substrate 2 described above. The ceramic substrate 12 has a desired wiring structure in the ceramic substrate 12 so that the contact interval (for example, 0.2 μm pitch) in the IC chip (test head 11) is expanded to the contact interval (for example, 1.0 mm pitch). Is formed.
As shown in FIG. 5, an ICU (inter connecting unit) 13 has pin contacts 17 disposed in through holes provided in a resin plate. In the ICU 13, the contact interval is not changed in principle. However, if desired, the contact interval can be enlarged at the ICU 13 portion. Examples of the resin material include polyester-based super heat-resistant resin.

  The basic structure of the pin contact 17 is the same as that shown in FIG. 3, and a metal, for example, a Ni alloy plated with gold can be used. It is preferable to improve the property.

The glass epoxy wiring board 14 may be basically the same as that used in the prior art. The wiring board 14 is connected to a tester according to a conventional method, like the wiring board 3.
The test head 11, the ceramic substrate 12, the ICU 13, and the wiring substrate 14 are firmly assembled using the stiffener T15 and the stiffener B16.
In order to cope with mass production of IC chips (devices), if a plurality of IC chips can be tested in the pre-process test, the efficiency increases accordingly. However, since the number of contact points that can be checked by the tester is usually limited (mostly 512 channels), it depends on the wiring structure in the IC tick.

Therefore, the number of IC chips to be tested at a time can be set as appropriate as desired. One chip, two chips, four chips, eight chips, and the like can be used.
FIG. 6 shows an example in the case of 4 chips. In FIG. 6, reference numeral 18 denotes a site for mounting an IC chip. The IC chip mount site can be set as appropriate even in the case of a probe card using a coaxial jumper cable (FIG. 1 shows an example of one chip).

[Demonstration Experiment 2]
A pre-process test of four IC chips each having 75 × 63 matrix bumps and 2573 bumps per 1DUT including a power source and a ground contact was tested using an ICU-shaped vertical probe card shown in FIG.
The pre-process test of the IC substantially having 2573 × 4 = 10292 bumps was within the desired range, and good test results were obtained.

  According to the present invention, a vertical probe card for performing a pre-process test of a highly integrated IC can be realized, and a general-purpose vertical probe card that can quickly and accurately respond to changes in IC specifications by replacing pin contacts. A vertical probe card capable of responding to changes in specifications quickly and accurately, and capable of high-efficiency manufacturing of dedicated vertical probe cards that can handle mass production of ICs required for intensive product launches Can be supplied together, making a valuable contribution to the advancement of IT technology.

It is a plane explanatory view showing the whole vertical probe card of the present invention. It is side surface explanatory drawing of the vertical probe card of this invention. It is explanatory drawing which shows an example of the pin contact used suitably for the vertical probe card | curd of this invention, (a) is a partially cutaway side view, (b) is an enlarged side view. It is sectional explanatory drawing of the vertical type probe card using ICU which is the 2nd Embodiment of this invention. It is principal part cross-sectional explanatory drawing of the vertical probe card using ICU which is the 2nd Embodiment of this invention. It is surface explanatory drawing of ICU which shows the example which test-processes four IC chips simultaneously with the vertical probe card using ICU which is the 2nd Embodiment of this invention. It is explanatory drawing which shows the example of the conventional probe type probe card. It is explanatory drawing which shows the example of the conventional vertical probe card.

Explanation of symbols

1: Socket 2: Ceramic substrate 3: Wiring substrate 4: Through hole 5: Overlapping portion (overlapping portion)
6: Coaxial jumper cable 7: Tube 8: Spring 9: Plunger 10: Hollow portion (at the center of the plunger) 11: Test head 12: Ceramic substrate 13: ICU (inter connecting unit)
14: Wiring board 15 (made of glass epoxy): Stefner T
16: Steffner B
17: Pin contact 18: Site for mounting IC chip 31: IC chip 32: Bump 33: Probe 34: Substrate 35: Wiring pattern 41: Inspected wafer 42: Electrode 43 (on the surface of wafer 41): Support plate 44: Bonding hole 45: Needle 46: Wiring substrate 47: Connection electrode 48: Internal wiring pattern 49: Electrode

Claims (4)

  A ceramic plate on which pin contacts that contact an IC burned on a wafer are arranged and a synthetic resin wiring board connected to a tester are connected by a coaxial jumper cable connector. Vertical probe card for process testing.   2. The vertical probe card according to claim 1, wherein the pin contact is disposed in a through-hole formed in a matrix provided on the ceramic plate and having a metal coating on a peripheral wall.   The ceramic board is electrically connected to connection terminals arranged at intervals in which the interval between the through holes is extended via a wiring circuit formed inside or on the surface of the ceramic board. 2. The vertical probe card according to 2.   A ceramic plate provided with pin contacts for contact with an IC burned on a wafer, a resin ICU having a contact interval corresponding to the enlarged contact interval of the ceramic substrate, and a synthetic resin connected to a tester A vertical probe card for a pre-process test, characterized in that it is made up of a wiring board made of metal.

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