JP2533431Y2 - IC wafer test probe - Google Patents

Description

[Detailed description of the invention] "Industrial application field" This invention is used for testing a semiconductor integrated circuit in a state of a semiconductor wafer, and is brought into contact with an electrode (pad) of the semiconductor wafer to connect the electrode to a wiring of a wiring board. IC to connect
The present invention relates to a wafer test probe.

[Prior Art] In a conventional probe card having a probe for IC wafer test, as shown in FIG. 4, one end of a needle-like probe 12 of tungsten wire is fixed to one surface of a wiring board 11, The ends are arranged on each side of a square, for example, and are bent at right angles to the side opposite to the wiring board 11 to be contact ends. These contact ends are formed by a plurality of pads (electrodes) on one chip of the IC wafer 13. The wiring board 11 is brought close to the IC wafer 13 in parallel and the contact end of the probe 12 is elastically contacted with each corresponding one of the pads 14 of the selected chip. The pad 14 is brought into contact with a test device through the probe 12 and further through the wiring on the wiring board 11 to perform a test. In this case, even if the parallelism between the wiring board 11 and the IC wafer 13 is slightly deviated, each probe 12 and the pad 14
Good contact has been obtained.

"Problems to be solved by the invention" Conventional probe cards for IC wafer testing are not suitable for high-speed signal transmission because the probes are needle-shaped, and signal waveforms are distorted, resulting in high-speed semiconductor integrated circuits. It was difficult to perform the test correctly.

From such a point, a plurality of contacts are formed on one surface of the insulating film in the same arrangement as the pad arrangement of the IC wafer, a microstrip line having one end connected to these contacts is formed on the insulating film, and the insulating film is formed. While holding it on the wiring board, connect the corresponding one of the microstrip lines to the wiring, elastically press the contacts to the pads on the IC wafer through the insulating film, and press the pads on the wiring board through the microstrip lines. Connection to wiring is conceivable.

In this way, a wafer test can be correctly performed on a high-speed semiconductor integrated circuit. However, if the contact forming surface of the insulating film is not exactly parallel to the IC wafer and is not in contact with the IC wafer, all the contacts cannot be brought into good contact with all the pads, and the contact forming surface must be exactly parallel to the IC wafer. There is a problem, and if there is a variation in the height of each contact, there is also a problem that a contact failure occurs.

[Means for Solving the Problems] The probe for IC wafer testing according to the present invention includes a contact holder made of a rigid body having a concave portion in the center of one surface, and a probe attached to the one surface side of the contact holder. An insulating film in which a plurality of contacts to be respectively contacted with the pads of the IC wafer are formed on an outer surface facing the concave portion, and a microstrip line is formed in which one end is connected to each of the contacts; and an insulating film thereof. An elastic plate provided in contact with the inner surface of the portion where the contact is formed, and the elastic plate is disposed in the recess on the opposite side of the insulating film from the insulating film, and comes into contact with the elastic plate in a plane, and A pressurizing body made of a rigid body having a plane parallel to the opposite side, attached to the bottom surface of the recess, and in point contact with the center of the plane of the pressurizing body An elastic body having a protrusion that is harder than the elastic plate; and a fixture formed integrally with the contact holder and for attaching the contact holder to a wiring board.

FIG. 1 shows an embodiment of the present invention. The wiring board 21 is usually circular, has a central hole 22 formed in the center thereof, and has a wiring 23 formed on one surface of the wiring board 21. The probe 24 is attached to the wiring 23 of the wiring board 21.

The probe 24 is provided with a contact holding body 25 made of a rigid body, and the contact holding body 25 is made of, for example, glass resin in order to impart heat resistance, and the wiring board 21 side is almost flat and fixed to the center thereof. The part 26 is integrally formed so as to protrude, and the fixing part 26 protrudes from the other surface of the wiring board 21 through the center hole 22. On the surface of the contact holding body 25 on the wiring board 21 side, the periphery of the fixing portion 26 is a contact surface 27 that protrudes further, and this contact surface 27 is perpendicular to the axis of the contact holding body 25 and Are in contact. Contact holder 25
The surface opposite to the wiring board 21 is a loose curved surface 28 slightly swelling outward. A concave portion 29 is formed at the center of the curved surface 28.
Are formed.

An insulating film 31 is disposed on the curved surface 28 side of the contact holding body 25, and a pad 14 of the IC wafer 13 is provided on an outer surface of a portion of the insulating film 31 facing the concave portion 29, as shown in FIGS. A plurality of contacts (so-called bumps) 32 to be contacted are formed, for example, by plating. The arrangement of the contacts 32 is the same as the arrangement of the pads 14 of the IC wafer 13. In FIG. 2, the contacts 32 are arranged along each side of the square. A microstrip line 33 having one end connected to each of the contacts 32
Is formed on the insulating film 31. In other words, insulating film
A conductive grounding layer 33g is formed over almost the entire inner surface of 31, and a signal line 33s having one end connected to each contact 32 is formed on the outer surface. Each signal line 33s extends outward with respect to the rectangular arrangement of the contacts 32. Insulating film 31 has folded portions 31a integrally extending in four directions corresponding to the respective sides of the rectangular arrangement of contacts 32, and microstrip lines 33 are distributed and extended to each folded portion 31a.

As shown in FIG. 1, this insulating film 31 has its ground layer 33g in contact with the curved surface 28 of the contact holder 25, and the folded portion 31a is folded back to the surface of the contact holder 25 on the wiring board 21 side. Touched. This folded part
A plastic connector 34 is interposed between 31a and wiring board 21. The plastic connector 34 has a large number of thin conductive wires embedded in an elastic insulating layer so as to be insulated from each other and both ends reach both surfaces, and electrically connects conductors in contact between both surfaces of the insulating layer to each other through the thin conductive wires. It is. The microstrip line 33 and the corresponding wiring 23 are connected by the plastic connector 34, respectively.

The contact holder 25 is fixed at the fixing part 26 by the fixing tool 35.
Are detachably attached to the wiring board 21. In this example, the fixing tool 35 is a nut, and is fastened to the screw formed on the outer periphery of the fixing portion 26 by the fixing tool 35. At this time, the contact surface 27
Are brought into contact with the wiring board 21. In this example, a pin is
The pin 36 is protruded and erected, and the pin 36 is inserted into a small hole formed in the wiring board 21 so that the contact holder 25 is
Is positioned with respect to

An elastic pressing means 37 is interposed between the contact holder 25 and the insulating film 31, and the contact 32 is connected to the pad 14 of the IC wafer 13.
So that it can be elastically contacted. FIG. 3 shows the elastic pressing means 37 separated from each other in the vertical direction, but they are sequentially in contact with each other. Insulating film
An elastic plate 38 made of silicon rubber or the like is in contact with the inner surface of the portion where the contact point 32 of 31 is formed, and a pressing body 39 made of a rigid body is opposed on a flat surface 41 on the surface of the elastic plate 38 opposite to the insulating film 31. Touched. The surface of the pressing body 39 opposite to the plane 41 is a plane 42 parallel to the plane 41. The pressing body 39 is formed of, for example, a glass plate. The elastic body 43 is adhered and fixed to the bottom surface of the pressing body 39 in the recess 29 in a point-like contact with the center of the flat surface 42 of the pressing body 39. The elastic body 43 is made of, for example, silicone rubber, and a protrusion 43a having a hemispherical tip protrudes, and the protrusion 43a is in elastic contact with the pressing body 39. The entire surface of the elastic body 43 facing the flat surface 42 may be formed into a spherical shape convex toward the flat surface 42. Elastic plate 38 elastic
It is preferable to make it softer than 43.

The probe 24 is connected to the pad 32 of the IC wafer 13
When the IC wafer 13 is pressed against the corresponding one of the IC wafers 13, the elasticity of the elastic plate 38 absorbs the variation in the height of the contact 32, and the elastic body 43 and the contact holder 25 and the IC
Absorbs the inclination of the wafer 13 and the contact holder 25
Is too close to the IC wafer 13 to some extent, the overdrive amount is absorbed by the elastic body 43. The pressing body 39 provides flatness, that is, the plane 41 is correctly parallel to the IC wafer 13, and the roles of the elastic plate 38 and the elastic body 43 are separated.

[Effect of the invention] As described above, according to the invention, the contact 32 is padded.
14 and contact 32 to the microstrip line.
Since it is connected to the wiring of the wiring board at 33, it is possible to correctly test even a high-speed semiconductor integrated circuit.
In addition, an elastic plate is used for the portion where the contact 32 of the insulating film 31 is formed.
38, the pressing body 39 and the elastic body 43 are elastically pressed against the pad 14, so that the contact 32 does not vary in height and the contact holding body 25 and the parallelism between the IC wafer are not affected. Nevertheless, each contact 32 can always be brought into good contact with the corresponding pad 14. For this reason, the probe of the present invention 24
When the probe 24 is attached to the wiring board 21, the probe 24 can be easily attached to the wiring board 21 without having to keep the parallelism strict. Further, since the elastic pressing means 37 is included in the probe 24, no adjustment is required even if the probe 24 is replaced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention mounted on a wiring board, FIG. 2 is an enlarged plan view of the insulating sheet 31, FIG. 3 is an exploded view of the elastic pressing means 37, and FIG. FIG. 2 is a sectional view showing a conventional probe card.

Claims (1)

(57) [Scope of request for utility model registration] 1. A contact holder made of a rigid body having a concave portion in the center of one surface, and an IC wafer pad attached to an outer surface of the contact holder attached to the one surface side and facing the concave portion. An insulating film on which a plurality of contacts to be contacted are formed, and a microstrip line having one end connected to each of the contacts, and an inner surface of a portion of the insulating film where the contacts are formed; And a rigid body which is disposed in the recess on the opposite side of the elastic film to the insulating film, is in flat contact with the elastic plate, and has a plane parallel to the surface on the opposite side. An elastic body that is attached to the bottom surface of the concave portion and is in point contact with the center of the flat surface of the pressing body, and is harder than the elastic plate; An IC wafer test probe, which is formed integrally with the tact holder and includes a fixture for attaching the contact holder to the wiring board.