JP4220586B2 - Probe card - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a probe card for a probe device used for electrical continuity test, operation test, defect detection, etc. of semiconductor elements such as IC, LSI, VLSI.
[0002]
[Prior art]
A probe card using a tungsten wire as a probe pin is known. This is a structure in which the tip of the tungsten wire is bent into a U-shape and brought into contact with the semiconductor evaluation electrode part, but the wire diameter of the tungsten wire is thick and it cannot follow the rapid trend of semiconductor miniaturization. There's a problem.
[0003]
Therefore, a vertical pin type probe card has been devised in which fine pins are planted substantially vertically on a substrate. For example, a method has been proposed in which a rod-shaped single crystal is formed on a silicon substrate by a VLS method (Vapore Liquid Solid) and the rod-shaped single crystal is used as a probe pin of a probe card (Japanese Patent Laid-Open Nos. 5-198636 and 5). -218156).
[0004]
In this method, for example, an SOI wafer is used to obtain a substrate having a wiring pattern and a rod-like single crystal grown at a predetermined position on the wire by the VLS method, and then conductive to the wire and the rod-like single crystal. The contactor having hundreds to thousands of probe pins corresponding to the electrodes of the IC with high positional accuracy can be obtained.
[0005]
In actual use, the contactor is connected to the tester part installed in the probe device body used for electrical continuity test, operation test, defect detection, etc., and in order to make contact with the electrode part of the semiconductor element and the tip part of the probe pin And mounted on a substrate having a wiring circuit.
[0006]
However, when a contactor is mounted on the board, the wiring inevitably becomes a super fine pitch wiring pattern corresponding to the enormous number of probe pins, and soldering is performed from the wiring part on the contactor to the wiring circuit part on the board. It is not possible to wire directly. Therefore, by using a flexible wiring circuit (hereinafter referred to as FPC) in which a wiring circuit is formed in a fan shape, the wiring pattern can be enlarged or bonded to the wiring circuit portion of ultra fine pitch with an anisotropic conductive adhesive film. (See FIG. 2).
[0007]
By adopting the above-described device, the circuit on the contactor becomes an enlarged wiring circuit, and the enlarged wiring circuit can be soldered to the wiring circuit on the substrate. However, even if the above-described measures are taken, the wiring circuit portion in which the ultra-fine pitch circuit is enlarged becomes wider and practically impossible with a single piece. Therefore, the FPC enlarged portions divided into a large number of pieces are overlapped. It becomes a structure.
[0008]
Therefore, in the mounting operation of the contactor on the substrate, before the FPC is bonded to the contactor with the anisotropic conductive adhesive film, a line is attached to the enlarged pattern portion of the FPC, and then the contactor is bonded to the contactor. . Next, wiring is performed at a predetermined position (position where connection to the tester portion is easy) through the through hole of the substrate.
[0009]
In the above mounting operation, since the wirings are randomly overlapped, removing the FPC and the solder part of the wiring and reusing the wiring part means that there is no space for soldering, even if there is space Since short circuits cannot be avoided, it is virtually impossible. In addition, the wiring work for enormous amounts of wiring requires a lot of time and labor, and in particular, a slight contact or the like breaks the pins or attaches dust.
[0010]
As described above, since the conventional probe card has a complicated wiring structure, even if it is necessary to replace only the contactor due to trouble in actual use of the probe card, for example, damage to some probe pins. There is a problem that the card must be exchanged in units of cards, and it is difficult to reproduce a probe card that has caused inconveniences such as breakage.
[0011]
[Problems to be solved by the invention]
The present invention has been made in view of the above-described prior art, and an object thereof is to simplify the assembly of the probe card, in particular, heavy labor related to wiring. It is an object of the present invention to provide a probe card that can be repaired by replacing only the contactor and its peripheral part when inconvenience such as breakage occurs.
[0012]
[Means for Solving the Problems]
As a result of intensive studies to solve the above-mentioned object, the present inventors have provided a detachable connector on the board, and connected the wiring conductor enlarged by FPC and the wiring circuit on the board through the connector. In the present invention, it is found that the vicinity of the connector is detachable, so that the connection work on the contactor side and the wiring work on the wiring circuit on the board side can be separated, and the workability of the connection work is greatly improved. It has come.
[0013]
That is, the present invention is a probe card comprising a multilayer printed wiring board having a wiring circuit corresponding to the number of probe pins, and a vertical pin type contactor fixed on the surface of the printed wiring board via a pedestal. , contactor described above, and an external lead circuit comprising a thin film S i monocrystalline layer of the above-mentioned probe pins and SOI substrate of silicon rod-like single crystal can respond to multiple pins, the above on the above-mentioned contactor external The lead-out circuit and the above- described wiring circuit on the above-mentioned printed wiring board are sequentially passed through a film-like anisotropic conductive adhesive, a plurality of flexible wiring circuits having a conductor pattern expanded in a fan shape , and a flexible wiring connector. , by dividing the wiring as another group, electrically connects the wiring enlargement portion of the flexible printed circuit by the structure for spatially superimposing It is, moreover a flexible printed circuit mentioned above and described connector for a flexible wiring, and being provided to be removable integrally with the contactor of the above at a position adjacent to the contactor fixing position of the printed wiring board of the above The above-mentioned probe card is characterized in that the probe pin is made of a single crystal grown by the VLS method.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view showing an example of the probe card of the present invention. A contactor in which a substantially vertical probe pin 1 is provided on a circuit 2 on a substrate (contactor substrate) 3 is provided via a pedestal 6 on one main surface of the substrate 7 having the wiring circuit 12. Although not shown, the contactor and pedestal 6, and the pedestal 6 and the substrate 7 are generally fixed with screws, but they are either fitted or connected to the former and / or the latter. As long as it can be divided by, it may be fixed by an adhesive.
[0015]
The circuit 2 on the contactor is electrically connected to the FPC 5 via the anisotropic conductive adhesive 4, and the FPC 5 is further connected to a connector 10 provided on the substrate 7. A terminal of the connector 10 is connected to a terminal 8 for external connection via a terminal 8 on the substrate 7 and a wiring circuit 12. It is preferable to provide the connector 10 close to the contactor because it is easy to work when dividing the probe card described later and a more compact probe card can be obtained. Various types of connectors 10 are known. When a flexible wiring connector is selected, a flexible one can be selected by the FPC 5, and circuit connection and circuit disconnection can be easily performed. Therefore, it is preferable.
[0016]
Since the probe card of the present invention has the above-described structure, the probe card, contactor, anisotropic conductive adhesive 4, PFC 5, and pedestal 6 (hereinafter referred to as a contactor and its related parts) The other parts except for (referred to as a printed circuit board part) can be integrally removed. Because of this feature, if the probe pin is damaged during use of the probe card, it can be easily repaired by replacing the contactor and its related parts. And the related parts and the printed circuit board part can be divided and worked separately, so that the workability can be remarkably improved and the probe card can be produced at low cost.
[0017]
The contactor used in the present invention may be manufactured by any method. However, the position is controlled by the VLS method so that a large number of rod-shaped single crystals are grown substantially perpendicular to the substrate, and the rod-shaped single crystals are used as probe pins. However, it is a preferable method because it can cope with the increase in the number of pins and the position controllability is easy.
[0018]
In the present invention, the height of the connector mounted on the board is such that the connector does not contact the object to be inspected before the tip of the probe pin contacts the object to be inspected when inspecting a semiconductor element or the like. Therefore, it is necessary to be lower than the tip of the probe pin to be mounted. For the above reasons, a thinner connector is more advantageous, but on the other hand, there is a minimum thickness for reasons such as ensuring mechanical strength to function as a detachable connector, According to the study by the present inventors, the minimum thickness is about 1.5 mm. On the other hand, the maximum limit of the thickness of the connector is preferably 5 mm or less from the viewpoint of controlling the parallelism of the tip of the probe pin.
[0019]
Although the method for producing the probe card of the present invention is illustrated by using a contactor obtained by the VLS method, the present invention is not limited to the following examples.
[0020]
First, for a substrate used for a contactor having a probe pin and a circuit, the thermal expansion coefficient of the obtained contactor must be close to the semiconductor element of the device under test with high positional accuracy. A silicon single crystal substrate is heavily used. In particular, a so-called SOI substrate in which two silicon single crystals on which an oxide film is formed is thermally fused and one of the single crystal layers is thinned by polishing or the like includes a thin film Si single crystal layer, an oxide film SiO2 layer, an Si single layer. A multilayer structure of a crystal layer and an oxide film SiO2 layer is preferable, and a circuit composed of a thin-film Si single crystal layer can be easily formed using this structure, which is preferable.
[0021]
That is, the thin film Si single crystal layer of the SOI substrate is processed using a method such as photolithography or etching to form an external extraction circuit (hereinafter referred to as a single crystal circuit), and a predetermined circuit on the single crystal circuit is formed. A gold bump is provided at the position. Next, for example, silicon is supplied by a method of introducing a gas such as silicon tetrachloride and hydrogen under heating conditions, and a silicon rod-like single crystal is grown substantially perpendicularly to the substrate at the position of the gold bump. A substrate having a rod-like single crystal is manufactured by the VLS method.
[0022]
Next, the lengths of the rod-shaped single crystals are made uniform by polishing, and further, the respective surfaces of the rod-shaped single crystals and the single crystal circuit are made conductive by a method such as coating a conductive material to obtain contactors. The contactor obtained by the above method has high probe pin position accuracy and is made of the same Si single crystal as the semiconductor element in characteristics such as thermal expansion coefficient. It is suitable as a contactor for a probe card.
[0023]
Next, in order to use the contactor produced by the above operation as a probe card, the contactor is mounted on a substrate having a wiring circuit, and a single crystal circuit connected to each probe pin is connected to the wiring circuit on the substrate. As the substrate, wiring corresponding to the number of probe pins is required, and the number thereof is as high as several hundred to several thousand lines. Therefore, a multilayer printed wiring board is usually used.
[0024]
However, in the case of connecting wirings with hundreds to thousands of lines, the wirings inevitably have an ultra-fine pattern, so that it is difficult to connect them directly. Therefore, it is preferable to use an FPC in which a conductor pattern is enlarged in a fan shape. Even in this case, the width of the enlarged portion becomes large, the size of the FPC itself becomes large, and it may not be possible to substantially mount it on the substrate. At this time, a structure may be employed in which a plurality of FPCs are used, wirings are divided into groups, and wiring enlarged portions of FPCs are spatially overlapped. In addition, about the connection of a single crystal circuit and the ultra fine pattern on FPC, it can connect using a commercially available film-form anisotropic conductive adhesive.
[0025]
When connecting an enlarged circuit of the FPC to a wiring circuit on the substrate, although the circuit on the FPC is enlarged, it is a fine pattern with a pitch of 0.4 to 0.6 mm, and from the substrate. Since these wirings overlap each other, it is not easy to connect to a desired position. For this reason, conventionally, conductive wires are bonded to the enlarged circuit on the FPC using a solder under a microscope, and the number is marked on each of the conductive wires, and then the FPC and the contactor are anisotropically conductive. A method of bonding with an adhesive, mounting on a board, and wiring to the board has been implemented. In the present invention, wiring work can be easily performed in a short time by mounting the connector in a desired position on the substrate in advance. That is, the assembly can be completed and the probe card can be obtained simply by mounting the contactor connected with the FPC on the substrate and inserting the FPC into the connector. In addition, it is desirable that the connector is provided on the board in advance so as to be adjacent to the contactor fixing position. However, in consideration of the FPC mounting space, generally the shortest distance between the contactor and the connector is 10 to 20 mm. It is preferable that
[0026]
The external output terminal portion of the board having the wiring circuit is generally formed in a contact shape, but the electrode shape that can be mounted on the board having another wiring circuit, or providing a connector instead of these, Any form may be used.
[0027]
Hereinafter, the present invention will be described in more detail based on examples.
[0028]
【Example】
[Example 1]
<Production of contactor>
A single crystal circuit was formed using an SOI wafer, and 460 silicon rod-shaped single crystals were grown on the single crystal circuit using the VLS growth method corresponding to the electrode positions of the semiconductor elements of the device under test. The rod-like single crystal was 18 μm thick and about 1500 μm long. The tip of the rod-shaped single crystal was polished to have a length of 1300 μm, and together with the single crystal circuit, after electroless nickel plating, gold plating was performed to a thickness of 1.5 μm. Furthermore, after insulating the probe pin side surface, the electrode part used for plating was cut | disconnected and the contactor was produced.
[0029]
<Connection of FPC to contactor>
Four polyimide film-based FPCs with 95 conductor lines expanded in a fan shape, and two FPCs with 40 conductor lines expanded in a fan shape on the opposite side are formed into a single crystal circuit of the contactor via an anisotropic conductive adhesive film. Connected.
[0030]
<Installation of SMT type FPC connector on board>
After solder paste was printed on the conductor terminal portion corresponding to the connector electrode on the disk-shaped multilayer resin substrate having a diameter of 20 cm, an SMT type FPC connector (manufactured by Japan Aviation Electronics Industry Co., Ltd.) was mounted and heat-bonded.
[0031]
<Assembly of probe card>
A contactor to which an FPC was joined via a 3 mm-thick titanium pedestal was mounted approximately at the center of the board on which the connector was mounted, and the end of the FPC was inserted and set in the connector to complete the assembly. The pedestal was fixed to the center of the substrate with fixing screws. This assembly time was completed in about 1 hour.
[0032]
[Example 2]
The operation up to the connection of the FPC to the contactor is the same as that of the first embodiment. However, in mounting the SMT type FPC connector on the substrate, the conductor terminal portion corresponding to the electrode of the SMT type FPC connector has a diameter of 10 cm. Solder paste was printed on the substrate on which the disk-shaped auxiliary substrate was mounted, and an SMT FPC connector (manufactured by Japan Aviation Electronics Industry Co., Ltd.) was installed and heat bonded. The probe card was assembled in the same manner as in Example 1. The assembly time at this time was about 1 hour.
[0033]
[Comparative example]
Using the same contactor as in Example 1, an insulation coated wire was soldered to the enlarged terminal portion of the FPC, and the wiring order was marked in units of 10 and bound. Next, the ultra fine part was joined to the pin chip through the anisotropic conductive adhesive film. About 8 hours were spent on these tasks.
[0034]
Next, the pin chips joined with the FPCs with a large number of insulation coated wires were mounted and fixed on the board, and the insulation coated wires were peeled one by one at the wiring joining position of the board and soldered. Since these operations are equipped with a group of fine pins, they require careful attention such as contact and adhesion of dust. As a result, it took about 30 hours to complete the operation. An error has occurred.
[0035]
【The invention's effect】
In the probe card of the present invention, since the circuit on the contactor and the wiring circuit on the board are electrically connected via the connector, the contactor, its related part, and the wiring circuit board part are easily divided. have. For this reason, it was possible to perform partial repairs that could not be achieved with conventional probe cards, and it was possible to perform wiring work in a divided state and to manufacture probe cards stably in a short time. It has a special effect and its industrial value is high.
[Brief description of the drawings]
FIG. 1 is a sectional view showing an example of a probe card of the present invention. FIG. 2 is a sectional view of a conventionally known probe card.
1 Probe pin 2 Circuit on contactor (single crystal circuit)
3 Contactor substrate 4 Anisotropic conductive adhesive 5 FPC
6 Pedestal 7 Substrate 8 Terminal on wiring circuit on substrate 9 Terminal on wiring circuit on substrate (for external connection)
10 Connector 11 Conductor 12 Wiring Circuit 13 Inside the Board Solder

Claims (2)

A probe card comprising a multilayer printed wiring board having a wiring circuit corresponding to the number of probe pins and a vertical pin type contactor fixed on the surface of the printed wiring board via a pedestal, wherein the contactor comprises a plurality of contactors. and an external lead circuit comprising a thin film S i monocrystalline layer of the probe pin and the SOI substrate of silicon rod-like single crystal to accommodate pins, and the external lead circuit on the contactor of the printed circuit board The wiring circuit is divided into groups through a film-like anisotropic conductive adhesive, a plurality of flexible wiring circuits in which a conductor pattern is expanded in a fan shape , and a flexible wiring connector in order , and the flexible wiring It is electrically connected by a structure for spatially superimposing the wiring enlargement portion of the circuit, yet the flexible Probe card is the line circuit and the connector for flexible wiring, and being provided to be removable in the contactor integral to the position adjacent to the contactor fixing position of the printed wiring board. 2. The probe card according to claim 1, wherein the probe pin is made of a single crystal grown by a VLS method.

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