JP3902497B2 - Probe card - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a probe card used for an electrical characteristic test of a semiconductor integrated circuit, and more particularly to a vertical needle type probe card in which probe pins are vertically attached to the probe card.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a vertical needle type probe card used for electrical characteristic testing of a semiconductor integrated circuit formed on a semiconductor wafer, a plurality of terminal portions (hereinafter referred to as bonding pads) of the semiconductor integrated circuit have outer peripheries of the semiconductor integrated circuit. In addition, it is used when electrically testing a flip chip type semiconductor integrated circuit provided inside.
[0003]
In this conventional vertical needle type probe card, a mechanical type using a spring pressure or a fluid type using a fluid pressure has been proposed as means for applying an elastic force to the probe pin. . As a conventional technique, a mechanical system is generally widely used. For example, as shown in JP-A-8-97260, a fluid system that can pressurize each probe pin evenly is used. Things are starting to attract attention.
[0004]
FIG. 3 is a cross-sectional view for explaining an example of a vertical needle type probe card using a mechanical method in the prior art. Referring to FIG. 3, this conventional vertical needle type probe card is composed of a base portion 1a and a head portion 2a. The base portion 1a is patterned with conductive wires 8a that transmit electrical signals from a tester (not shown) to each probe pin 9a, and a gold plate serving as a contact portion with the probe pin 9a at the tip portion of the conductive wire 8a. 15 is provided. Further, the head portion 2a has a plurality of guide holes 10a and probe pins 9a therein, and each probe pin 9a is configured to be able to move up and down independently in the vertical direction according to the guide holes 10a. . The base portion 1a and the head portion 2a are fastened and integrated with a screw (not shown) to constitute a vertical needle type probe card.
[0005]
Next, a state in which the conventional vertical needle type probe card is brought into contact with the semiconductor integrated circuit will be described with reference to FIG. Prior to the start of contact, the probe pins 9a and the semiconductor wafer 12 are in a separated state, and contact is possible by raising the wafer stage 13 on which the semiconductor wafer 12 is mounted to an arbitrary height.
[0006]
First, the wafer stage 13 is raised to bring the tip of the probe pin 9 a into contact with the bonding pad 14 of the semiconductor wafer 12. If the wafer stage 13 continues to rise, the probe pins 9a are pushed up according to the guide holes 10a, and the bases of the probe pins 9a come into contact with the gold plate 15. At this time, the wafer stage 13 is raised to a preset height so that a certain amount of needle pressure is applied to the bonding pad 14. The probe pins 9a can be electrically connected to the tester by contacting the semiconductor wafer 12 and the gold plate 15, and pass / fail judgment is performed by transmitting an electrical signal from the tester to the semiconductor integrated circuit. After the test is completed, the wafer stage 13 is lowered to the original position and stopped.
[0007]
Here, if the wafer stage 13 is raised too much, an excessive stylus pressure is applied to the bonding pad 14 and may cause the bonding pad 14 to be damaged. In order to avoid this problem, the back of the probe pin 9a may be damaged. The portion has a curved shape and has a spring property, and when excessive needle pressure is applied, the back portion of the probe pin 9a bends to act as a cushion that absorbs needle pressure.
[0008]
On the other hand, the vertical needle type probe card adopting the fluid method in the prior art has an advantage that the needle pressure can be uniformly applied to each probe pin by using a fluid instead of a spring. Has not been realized.
[0009]
[Problems to be solved by the invention]
The present invention has been made in order to eliminate the problems that are difficult to solve with the conventional mechanical probe card as described above, and is intended to solve by adopting a fluid system instead of the mechanical system. is there.
[0010]
There are the following problems as problems with the conventional mechanical system. First, the first problem is that as the number of contacts with the semiconductor wafer increases, metal fatigue due to bending and stretching occurs at the back of the probe pin, increasing the variation in height of each probe pin. It is a point to end up. When the variation in the height of the probe pin becomes large, a difference occurs in the needle pressure of each probe pin, causing the following problems. That is, a probe pin with a weak needle pressure cannot normally contact a bonding pad, and when a semiconductor integrated circuit is determined to be good or bad, there is a possibility that a good product is erroneously determined as a defective product. Further, a probe pin having a high needle pressure applies a needle pressure more than necessary to the bonding pad, so that the bonding pad is damaged.
[0011]
The second problem is that when the probe card main body is attached with an inclination or the semiconductor wafer is warped, a difference occurs in the needle pressure between the probe pins. Similar to the first problem, this also has the disadvantage that the probe pin cannot be contacted normally, so that the pass / fail judgment is wrong or the bonding pad is damaged.
[0012]
The third problem is that when the tip of the probe pin is polished, all the probe pins cannot be polished uniformly if the height of the probe pins varies. A probe pin with a weak needle pressure cannot remove foreign matter or the like adhering to the needle tip, and a probe pin with a high needle pressure increases the amount of polishing, resulting in a non-uniform needle tip diameter.
[0013]
Accordingly, the present invention has been made to solve these problems, and by adopting a fluid system as a probe pin pressurizing mechanism, the pressure applied to the probe pins is evenly distributed, and all the probe pins are made the same needle. Reduce contact failure between the probe pin and the semiconductor wafer by making contact with pressure, and also provide cushioning to the probe pin so that excessive needle pressure is not applied during contact, reducing damage to the bonding pad The object is to provide a probe card for this purpose.
[0014]
[Means for Solving the Problems]
The present invention is a vertical needle type probe card for testing electrical characteristics of a semiconductor integrated circuit by contacting probe pins vertically to a bonding pad of a semiconductor integrated circuit formed on a semiconductor wafer, and a hollow portion; A plurality of cylinders that are vertically connected through the hollow portion, a base portion having a piston that is provided inside each cylinder and abuts against the probe pin, and is fastened and integrated with the base portion, wherein is composed of a head portion having a guide hole for guiding the probe pins, the hollow portion flowable insulator in said each cylinder and is filled, the needle pressure applied to the respective probe pins during the contact the It is made to disperse | distribute so that it may become equal via the said fluid insulating material irrespective of the fluctuation amount of a piston.
[0015]
Further, the present invention is pre-Symbol piston and the probe pins are in contact via a spacer when fastening the said and the base unit head, said piston and said spacer and said probe pins together It can move up and down.
[0016]
Further, the present invention is the in the guide hole provided in the head portion conductive cylinder is fitted, after fastening the said base portion said head portion, the outer periphery of the inner wall and the probe pins of the conductive cylinder so as to slidably conductively contact with, also, above the base portion is patterned conductor for transmitting electrical signals from the tester, when fastening the said head portion and said base portion, said patterned conductor It said conductive cylindrical and said tester in contact with the probe pins are to be electrically conductive.
[0017]
Further, the present invention, the hollow portion spring through the flowable insulating material to a portion of the inner wall of the is provided, the needle pressure when excessive probe pressure is applied to the respective probe pins during the contact , so as to absorb the compression of the spring.
[0018]
Further, the present invention is a structure wherein the spring is inserted into the insertion hole opened in the inner wall of the hollow portion, which expands and contracts by the pressure fluctuations exerted on the flowable insulating material through the same said piston which is inserted into the insertion holes has also the spring, varies the free length by the pressure adjusting screw, and adjustable needle pressure applied to the probe pin, Moreover, the flowable insulating material is a silicon oil.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a main part of a probe card for explaining an embodiment of the present invention, and FIG. 2 is a plan view (a) and a cross-sectional view (b) showing a schematic structure of the entire probe card. ). The same parts as those in the prior art will be described using the same reference numerals.
[0020]
First, as shown in FIG. 2, the probe card of the present invention is composed of two parts, a base part 1 and a head part 2, and the base part 1 further comprises members 101, 102, 103 for assembly and maintenance. It is easy to configure. Finally, the base portion 1 and the head portion 2 are fastened by a fastening screw 22 so as to be integrated.
[0021]
As shown in FIG. 1, each base portion 1 is made of an insulating material such as a hard resin, and a hollow portion 16 for filling a fluid insulating material is formed inside the base portion 1. A plurality of holes connected to the hollow portion 16 and serving as the cylinder 3 are formed in the vertical direction 103 so that all the cylinders 3 communicate with the hollow portion 16. The cylinder 3 is not a straight hole, but a stepped portion 17 is formed in the upper opening connected to the hollow portion 16 by a hole formed in the member 102, and a stepped portion 18 is provided in the lower opening when the member 103 is processed. As shown in FIG. 1, the step portion serves as a stopper for preventing the piston 5 and the spacer 6 inserted into the cylinder 3 from jumping out and falling off. The cylinders 3 are arranged in one-to-one correspondence with the positions of the bonding pads 14 of the semiconductor wafer 12 to be measured. The probe card shown in FIG. 2 is an example when testing a semiconductor wafer in which bonding pads are arranged in a matrix on a semiconductor integrated circuit.
[0022]
Further, as shown in FIG. 1, the hollow portion 16 and the cylinder 3 are filled with a fluid insulating material 4 such as silicon oil and installed on the head portion 2 side through a metal piston 5 and a spacer 6. The pressure can be evenly transmitted to each probe pin 9. Further, an insertion hole 20 for inserting the spring 7 and the piston 19 is provided in a part of the member 101 constituting the hollow portion 16 so that excessive pressure applied to the probe pin 9 can be absorbed. It compresses and can absorb the excessive pressure applied to the probe pin 9. Also, the piston 19 and the spring 7 are attached to the member 101 integrally with the pressure adjusting screw 21, and the needle pressure applied to the probe pin can be arbitrarily adjusted by changing the free length of the spring 7 with the pressure adjusting screw 21. Yes. The insertion hole 20 also serves as an injection hole for filling the fluid insulating material 4. Further, the base portion 1 is patterned with a conductive wire 8 for transmitting an electrical signal from a tester (not shown) to the probe pin 9.
[0023]
Next, as shown in FIG. 1, the configuration of the head portion 2 is formed of a hard resin or the like as in the base portion 1 and accommodates the probe pins 9 that come into contact with the bonding pads 14 of the semiconductor integrated circuit and the probe pins 9. A plurality of guide holes 10 are provided, and a conductive cylinder 11 with which the outer periphery of the probe pin 9 contacts is fitted into the guide holes 10. The probe pin 9 is made of tungsten or the like, and has a two-stage structure with a thin tip and a thick upper end. A step portion is provided in the lower portion of the guide hole 10 to prevent the probe pin 9 having a stepped structure from dropping off. The probe pin 9 is always in slidable contact with the inner wall of the conductive cylinder 11 to enable electrical connection with the tester.
[0024]
When the base portion 1 and the head portion 2 having such a structure are overlapped and fastened with the fastening screw 22 (FIG. 2), the piston 5 and the probe pin 9 are brought into contact with each other via the spacer 6, and the piston attached It becomes possible to move up and down integrally as a probe pin. Here, the spacer 6 is a member for transmitting pressure by connecting the piston 5 and the probe pin 9 which are divided into the base portion 1 and the head portion 2, and the piston 5 and the probe pin 9 are connected to each other. Since the structure is divided rather than being manufactured in one piece, maintenance such as assembly or replacement is facilitated. Further, by slightly projecting the conductive cylinder 11 from the guide hole 10, when the base portion 1 and the head portion 2 are fastened, the conductive wire 11 is reliably brought into contact with the conductor 8 and the tester and the probe pin 9 are electrically connected. Making it easy.
[0025]
Next, the operation of the probe card according to the embodiment of the present invention as described above will be described with reference to FIG. As a feature of the present invention, first, a fluid-filled insulator (for example, silicon oil) filled in the probe card and a piston are provided, and the pressure applied to each probe pin during contact is evenly distributed. . Another feature is that an excessive needle pressure applied to each probe pin can be absorbed by compression of the spring by providing one spring for absorbing the needle pressure.
[0026]
In the vertical needle type probe card of the present invention, the probe pins 9 and the semiconductor wafer 12 are in a separate state before the contact is started, and the wafer stage 13 on which the semiconductor wafer 12 is mounted is raised to an arbitrary height. Is possible. FIG. 1 shows this contact state. It is assumed that a plurality of flip chip type semiconductor integrated circuits in which bonding pads 14 are arranged in a matrix are formed on the semiconductor wafer 12 used for measurement.
[0027]
First, when the wafer stage 13 is raised, the tip of the probe pin 9 comes into contact with the bonding pad 14 of the semiconductor wafer 12. When the wafer stage 13 continues to rise, the probe pins 9 pushed up according to the conductive cylinder 11 push up the spacer 6 and the piston 5 to generate pressure on the fluid insulator 4 inside the cylinder 3. Since the pressure generated in the cylinder 3 is uniformly applied to each piston 5 via the fluid insulator 4, all the probe pins 9 can contact the bonding pad 14 with the same needle pressure. Even if there is a difference in the amount of fluctuation of the piston 5 due to wear of the probe pin 9, warpage of the semiconductor wafer 12, variation in bonding pad height, etc. (FIG. 1 shows this state) Such needle pressure becomes uniform.
[0028]
The wafer stage 13 is raised to a predetermined height so that a certain amount of needle pressure is applied to all the probe pins 9 and an electrical test is performed. If the wafer stage 13 is raised too much, excessive needle pressure is applied to the semiconductor wafer 12. If this is added, the bonding pad 14 may be damaged. In order to avoid this problem, a spring 7 for absorbing excessive pressure is installed in the hollow portion 16 connected to the cylinder 3. The spring 7 is compressed via the fluid insulating material 4, and the probe pin 9 is compressed. The bonding pad 14 is prevented from being damaged by imparting cushioning properties thereto. After the test is completed, the wafer stage 13 is lowered to the original position, and the next semiconductor integrated circuit is moved below the probe pins. By repeating this series of operations, an electrical test of the semiconductor integrated circuit on the semiconductor wafer is performed.
[0029]
【The invention's effect】
Since the probe card of the present invention is configured as described above, the following effects can be obtained. The first effect is that a stable electrical test can be performed by reducing poor contact with a semiconductor wafer. The reason is that the needle pressures of all the probe pins can be made uniform by dispersing the needle pressures of the probe pins.
[0030]
The second effect is that the quality of the semiconductor integrated circuit can be improved by preventing damage to the bonding pad which is a terminal portion of the semiconductor integrated circuit. The reason is that by providing a spring for absorbing needle pressure, the probe pin is cushioned at the time of contact to prevent excessive needle pressure from being applied to the bonding pad.
[0031]
A third effect is that the amount of polishing at the tip of the probe pin can be made uniform. The reason is that the needle pressure of all the probe pins can be made uniform.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a principal part of an embodiment of a probe card according to the present invention.
2A and 2B are a plan view and a cross-sectional view showing a schematic structure of the entire probe card of the present invention.
FIG. 3 is a cross-sectional view illustrating a conventional probe card.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 1a Base part 2, 2a Head part 3 Cylinder 4 Flowable insulator 5 Piston 6 Spacer 7 Spring 8, 8a Conductor 9, 9a Probe pin 10, 10a Guide hole 11 Conductive cylinder 12 Semiconductor wafer 13 Wafer stage 14 Bonding pad 15 Gold plate 16 Hollow portion 17, 18 Step portion 19 Piston 20 Insertion hole 21 Pressure adjusting screw 22 Fastening screw 101, 102, 103 Member

Claims (8)

Vertically to contact the probe pins to the bonding pads of the semiconductor integrated circuit formed on a semiconductor wafer, a vertical needle type probe card for testing electrical characteristics of a semiconductor integrated circuit,
A base portion having a hollow portion, a plurality of cylinders vertically connected through the hollow portion, and a piston that is provided inside each cylinder and contacts the probe pin;
A head portion that is fastened and integrated with the base portion and includes a guide hole that guides the probe pin;
Consisting of
The hollow portion flowable insulator in said each cylinder and is filled, the needle pressure applied to the probe pin becomes evenly through the flowable insulating material regardless of the amount of change of said piston during said contact The probe card is characterized by being dispersed as described above. Said piston and said probe pin, characterized in that the movable up and down the the contact via a spacer when fastening the base portion and said head portion, said piston and said spacer and said probe pins together The probe card according to claim 1 . Wherein the said guide hole provided in the head portion conductive cylinder is fitted, after fastening the said base portion said head portion slidably and the outer periphery of the inner wall and the probe pins of the conductive cylinder The probe card according to claim 1, wherein the probe card is in conductive contact. Wherein the base portion is patterned conductor for transmitting electrical signals from the tester, when fastening the said base portion and said head portion, said patterned conductors and said conductive cylinder and is in contact with said tester said probe The probe card according to claim 3, wherein the pin is electrically connected. Spring is provided through said flowable dielectric material to a portion of the inner wall of the hollow portion, the needle pressure when excessive probe pressure is applied to the respective probe pins during the contact, the compression of the spring The probe card according to claim 1 , wherein the probe card absorbs the probe card. The spring is inserted into the insertion hole opened in the inner wall of the hollow portion, claim 5, characterized in that the stretchable similarly by pressure fluctuations exerted on the flowable insulating material through the inserted the piston insertion hole Probe card as described in The probe card according to claim 5 or 6, wherein a free length of the spring is adjustable by a pressure adjusting screw to adjust a needle pressure applied to the probe pin. The probe card according to claim 1, wherein the fluid insulating material is silicon oil.

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