JPH03177038A - Semiconductor lsi inspecting device - Google Patents

Abstract

PURPOSE:To facilitate conduction for high density electrodes and enable high precision measurement of high speed electrical characteristics without giving thermal stress by sticking a hard needle-like probe into a solder ball to realize conduction and forming the needle-like probe at the extremity of a coaxial insulated conductor. CONSTITUTION:Many solder balls 3 are arranged on the surface of a semiconductor element 2 to be inspected. These solder balls 3 adhere the electrodes of the semiconductor element 2. A plurality of coaxial cables 16 are arranged opposing these many solder balls 3. Their insulated conductor 14 are pointed to form needle-like probes and are made of hard metal. The extremity of this coaxial cable 16 passes through an insulating substrate 18 and a supporting substrate 19, and an electrically conductive adhesive or solder makes shield material 12 conductive by a solidified electrically conductive material 20. The other end of the insulated conductor 14 of the coaxial cable 16 is connected to a pad 22 provided on a wiring substrate 21 having an inspection circuit by solder 23. When the supporting substrate 19 is driven downwardly, the insulated conductors stick the solder balls 3 to surely and quickly conduct.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an apparatus for testing the electrical performance of a semiconductor LSI in an operating state, and particularly to a device for quickly and reliably contacting and separating a large number of electrodes of a semiconductor LSI. This invention relates to a semiconductor LSI inspection device with an improved probe mechanism so that the probe mechanism can be
A semiconductor element (chip) 2 for SI is provided and separated for use. FIG. 4(B) shows the semiconductor element 2
It is a perspective view which expanded and showed one of them. A large number of electrodes 4 are arranged on the surface of the semiconductor element 2 along its periphery.

In order to industrially produce a large number of such semiconductor devices 2 and to test their electrical performance, a probe 6 such as a tungsten needle protruding diagonally from a probe card 5 is used as shown in FIGS. 5 and 6. A method is used in which the electrode 4 is rubbed with contact pressure using the deflection of the probe 6 to make contact, and the electrical characteristics thereof are inspected.

As the density of semiconductor devices continues to increase, chip-shaped semiconductor devices 2 having solder balls 3 on their electrodes for solder welding connections as shown in FIG. The method of facing the surfaces and connecting via the solder balls 3 is suitable for high-density packaging and high-yield batch connection, and its applications are expanding.

As the density of semiconductor devices increases and operation tests using high-speed signals become necessary, the present invention provides an inspection method and an inspection device that enable characteristic inspection of semiconductor devices that have solder balls on their electrodes for solder welding connections when the density of semiconductor devices increases and operation tests using high-speed signals become necessary. Japanese Patent Publication No. 58-731
The technique described in Publication No. 2 is publicly known. FIG. 9 is an explanatory part of the above-mentioned known technique, and FIG. 10 is an enlarged sectional view of the main part. 9 is a probe card, and the power supply conductor JFy8
was used as the reference layer. A signal conductor wiring 7 having a constant characteristic impedance is buried.

A protruding electrode 1O is provided to face a large number of solder balls 3 attached to an electrode (not shown) on the surface of the semiconductor cord 2.

In this known technique, the probe card 9 is heated with heat [11], the protruding electrodes 10 are pressed against the solder balls 3, the solder is melted and conductive, and signals are sent and received to test semiconductor devices. After this, the multilayer substrate 9 is heated again to melt the solder and the protruding electrodes 10 are pulled out.

[Problem to be solved by the invention]

In the conventional probe card testing method shown in FIGS. 5 and 6, due to the shape of the probe 6, the concentrated inductance there is large, and there is a limit to testing using high-speed signals. In other words, if we take the characteristic impedance of the signal line on the probe card as ■ and let the lumped inductance of the probe be L, then the time constant becomes L/■, R = 50Ω, L = 50
In the case of nH, it is 1 nS, and when handling such a high speed No. 43, the waveform becomes dull and accurate inspection cannot be performed. Therefore, it is usually limited to direct current characteristic testing. Furthermore, in the above-mentioned broaching method, there is a limit to the spatial arrangement of the probes, and it is not possible to cope with an increase in the density and the total number of electrodes of a semiconductor device.

On the other hand, as shown in Fig. 9 and Fig. 1O, conduction is established between the semiconductor element electrode and the protruding electrode by melting solder, and the signal line is formed into a line with a constant characteristic impedance. In the method of testing using a probe car 1-, it is possible to test electrical characteristics at high speed, but since it is necessary to melt the solder balls on the electrodes of the semiconductor device, it causes thermal stress to the semiconductor device and also makes it difficult to operate. The drawbacks are that the performance is poor and the inspection time is long.

The present invention has been made in view of the above-mentioned circumstances.

It is possible to quickly and easily establish conduction to the high-density electrodes of a semiconductor element without applying thermal stress to the semiconductor element, and to maintain high-speed electrical characteristics with high precision.
The purpose of the present invention is to provide a semiconductor LSI testing device that can be used to test a semiconductor LSI.

[Means to solve the problem]

The basic principle of the LSI testing device of the present invention, which was created to achieve the above object, is as follows.

The LSI testing device according to the known technology shown in FIG. 9 and FIG. Since it is additionally melted, it takes 81 steps and takes a long time.

b. It has a thermal effect on the semiconductor element.

There was a problem.

Therefore, the present invention does not melt the solder balls, but pierces the solder balls with a hard needle-like probe to establish continuity.

In order to cope with higher density and to test high-speed electrical characteristics, a master needle probe is formed at the tip of the coaxial cable core.

Based on the above-mentioned principle, the inspection apparatus of the present invention has a specific configuration for adapting it to a practical aspect.
A plurality of coaxial cables are arranged in correspondence with the solder balls attached to the electrodes, and the tip of the core wire of the coaxial cable is made of a metal harder than the solder, and
The present invention is characterized in that the tip of the hard metal core wire is sharpened to serve as a probe, so that it can be inserted into a solder ball to provide electrical continuity.

[Effect]

According to the above configuration, the tip of the needle-like probe easily breaks through the oxide film on the surface of the solder ball, ensuring that the metals come into contact with each other and are electrically conductive.

Since the operations described above can be performed at room temperature, no heating means or heating operation is required, and the operations can be performed quickly with simple equipment. Furthermore, since the process is carried out at room temperature, there is no risk of thermal effects on the semiconductor elements.

Furthermore, since the above-mentioned probe is formed at the tip of the coaxial cable core wire, the overall impedance from the probe to the test circuit can be matched, and high-speed signals can be tested without disturbing them.

〔Example〕

FIG. 2 shows an embodiment of a semiconductor LSI testing device according to the present invention, and is a schematic cross-sectional view. Since the details will be described later with reference to FIG. 1, the overall configuration will first be briefly described.

Reference numeral 2 denotes a semiconductor element to be inspected, and a large number of solder balls 3 are arranged on the surface of the semiconductor element. These solder balls 3 are attached to electrodes (not shown) of the semiconductor element 2. A plurality of coaxial cables 16 are arranged opposite to the plurality of solder balls 3. The tip of the core wire 14 is sharpened to form a needle-like probe, and is made of hard metal. Here, hard means clearly higher hardness than solder.

The distal end of the coaxial cable 16 passes through the insulating substrate 18 and the support substrate 19, and conducts the shielding materials 12 with each other through a conductive material 20 in which conductive adhesive or solder is solidified. The insulating substrate 18 and supporting substrate 19 are
Constructed of free-cutting ceramics, acrylic, polyimide, or engineering plastics.

The other end of the core wire 14 of the coaxial cable 16 is connected to a pad 22 provided on a wiring board 21 having a test circuit.
The solder 23 connects both mechanically and electrically.

When the supporting J& plate 19 is driven downward in the figure, the core wire 14 having a hard needle-like tip pierces the half-U1 ball 3, and conduction is established reliably and quickly.

FIG. 1 is an enlarged cross-sectional view of the main part of the above embodiment.

16 is a coaxial cable, 14 is its core wire, 12 is a shielding material, and 13 is an insulating tube.

When carrying out the present invention, the shield material 12 may be a wound metal wire (for example, a copper wire), a metal net, or a metal foil.

The insulating tube 13 of this example is made of polytetrafluoroethylene (PolLytetraflLuoroethyien).
e).

The core wire 14 in this example is made of tungsten, and one end 14a thereof is sharpened by electrolytic polishing.

When carrying out the present invention, the above-mentioned core wire 14 can also be made of stainless steel.

The insulating substrate 18 is provided with a through hole 18a through which the core wire 14 can be accurately positioned.

A sleeve 15a is fitted onto the core wire 14 described above. This sleeve 15a is made of beryllium copper, but when carrying out the present invention, it can also be made of brass, nickel silver, copper, or stainless steel, and the sleeve 15a is plated with gold or rhodium. may be applied.

The sleeve 15a is fixed to the core wire 14.

The preferred fixing method is crimping, spot welding, or laser welding.

The inner diameter of the sleeve 15a is configured to be equal to the outer diameter of the core $9i14, and the outer diameter is configured to be approximately equal to the inner diameter of the through hole 19a provided in the support substrate 19 made of an insulating material.

The vicinity of the end of the shielding material 12 that wraps around the outer periphery of the polytetrafluoroethylene insulating tube 13 on the side closer to the support substrate 19 is electrically connected to each other by a conductive material 20 made of a conductive adhesive. Fixed 6 Coaxial cable 16 marked with drawing reference number in Figure 1
Although it is a single component, it is shown with the central part cut and removed, so for convenience of reading, drawing reference number 16 is written at each end of the figure.

Shield material 12. Insulating tube 13. Similarly, the core wire 14 is also marked on both ends.

Hereinafter, for convenience of explanation, the end closer to the support substrate 19 will be referred to as one end, and the end on the other side will be referred to as the other end.

Reference numeral 21 denotes an impedance-matched wiring board, which is connected to a test circuit (not shown).

At the other end of the coaxial cable 16, the core wire 14 is connected to a core pad 22 of a wiring board 21 with solder 23, and is mechanically fixed and electrically conductive. Further, the other end of the shield material 12 is connected to a grounding member of the wiring board 21 by solder.

Reference numeral 25 shown in FIG. 1 is a ground terminal, which is constructed by fitting and fixing a sleeve 15b onto the core wire 14'.

In this way, a plurality (in this example, a plurality of three or more)
The core wires are for power supply and signal input, respectively.

and used for grounding.

The conductive material 20 may be a solid such as solder,
A conductive synthetic resin that is easily elastically deformable can also be used.

With such a configuration, the probe formed at one end of the core wire 14 can be given some elasticity.

FIG. 3 shows a different embodiment from the above.

In this embodiment, two support substrates 19b and 19c are stacked on top of each other.

The core wires 14 and 14' of the inspection device of this example are brought into contact with the surface plate 24, and with their tips aligned on the same plane, the support substrates 19b and 19c are placed oppositely along the contact surface as indicated by arrows C and D. When a force in the direction is applied, the sleeve 15a.

The same 15b receives a force in the shearing direction.

Sleeves L5a and 15b subjected to the force in the above shearing direction
is locked from sliding in the axial direction, and the tips of the core wires 14 and 14' are fixed in the same plane. As a result, an inspection device is constructed in which the flatness of the tip of the probe formed at one end of the core wire 14, 14' is good.

Next, we will discuss the characteristic impedance of the coaxial cable.

A coaxial cable generally has a concentric cross-sectional shape, and a core wire is arranged at the center. 11' [The diameter is d (unit: ffn).

An outer conductor is provided around the core wire with an insulator interposed therebetween. Let its diameter be D (φ4 mm).

The aperture of the external conductor is covered with a cover film.

The impedance Zo (unit: Ω) of the coaxial cable is expressed by the following formula.

Here, ε is the dielectric constant ds of the insulator is the diameter of the shield wire (unit -). For example, if the characteristic impedance Zo is 50Ω and the outer diameter of the insulator is 0.2 m
To make a coaxial cable, the insulator must have a relative dielectric constant ε,
When polytetrafluoroethylene with a diameter of 2.1 is used and a copper wire with a shield wire diameter ds of 0.03+w+ is used, a tungsten wire with an outer diameter d of 0.073 mm may be used as the core wire.

Strip the tungsten wires at both ends of the coaxial cable above,
One end is connected to the electrode of the test circuit, and the other end is sharpened by electrolytic polishing and used as a probe. By doing so, it is possible to minimize the mismatched part of the characteristic impedance. Reduce disturbances such as accent.

High-speed electrical signals can be propagated accurately.

〔Effect of the invention〕

As explained above, since the semiconductor LSI testing device of the present invention has a structure in which the tip of the needle-like probe is inserted into the solder ball to establish conduction, there is no need to heat the solder to melt it. (b) It does not require a heating operation, so the operation is quick and easy; ())) It does not require a heating operation, so the structure is simple.
No thermal effect on SI.

Furthermore, since the probe is formed at the tip of the coaxial cable core wire, it is easy to construct a high-density probe that is compatible with high-density electrodes, and impedance matching is easy, making it possible to measure high-speed electrical characteristics with high precision. I can do it.

[Brief Explanation of the Drawings] Figures 1 and 2 show an embodiment of the semiconductor LSI device according to the present invention. be. FIG. 3 is a sectional view of a main part of an embodiment different from the above. FIG. 4(A) is a perspective view of a wafer, and FIG. 4(B) is a perspective view of a semiconductor element. 5 and 6 show conventional probe cards,
FIG. 5 is a sectional view, and FIG. 6 is a plan view. 7 to 10 are explanatory diagrams of known techniques, and FIG. 7 is a perspective view of a semiconductor element provided with solder balls. FIG. 8 is a perspective view depicting the semiconductor element and the wiring board;
FIG. 9 is a side view, and FIG. 10 is a sectional view of the probe card. 12... Shielding material, 13... Insulating tube, 14
．． 14'...Core wire, 14a...Tip with one end of the core wire pointed, 18...Insulating board, 18a...Through hole, 15a, 15b...Sleeve, 16...Coaxial cable, 18 ... Insulating substrate, 18a... Through hole, 19... Supporting substrate, 19a... Through hole, 19b, 19c... Supporting substrate, 20... Conductive material, 21... Wiring board, 22... Pad for core wire, 2
3...Solder.

Claims (1)

[Claims] 1. A plurality of coaxial cables are wired in correspondence with solder balls attached to electrodes of a semiconductor LSI, and the tip of the core wire of the coaxial cable is made of a metal harder than solder. A semiconductor LSI testing device characterized in that the tip of the hard metal core wire is sharpened to serve as a probe and can be inserted into a solder ball to establish continuity. 2. The core wires of the plurality of coaxial cables are inserted into through holes provided in the support plate made of electrically insulating material, and the shields of the plurality of coaxial cables are mutually connected. 2. The semiconductor LSI inspection device according to claim 1, wherein the semiconductor LSI inspection device is bonded to the semiconductor LSI with a conductive adhesive. 3. The semiconductor L according to claim 1 or 2, wherein the coaxial cable is connected to a test circuit.
SI inspection equipment. 4. Claim 1, wherein the coaxial cable is connected to a wiring board having a specific impedance, and the wiring board is connected to a test circuit.
Or the semiconductor LSI inspection device described in 2. 5. A metal sleeve having an inner diameter substantially equal to an outer diameter near the tip of the core wire and an outer diameter substantially equal to the inner diameter of the through hole of the support plate is fitted around and fixed to the core wire near the tip. 4. The semiconductor LSI testing device according to claim 2, wherein the semiconductor LSI testing device is characterized in that: 6. The number of supporting plates is plural, and they are stacked in contact with each other, and the sleeve is slidably fitted into a through hole provided in each of the plurality of supporting plates. When a force is applied to the plurality of support plates in the direction of sliding along their contact surfaces, the inner wall surface of the through hole of the support plate applies a force in the shearing direction to the sleeve, causing the sleeve to slide. 5. The semiconductor LSI testing device according to claim 4, wherein the semiconductor LSI testing device has a structure that prevents sliding of the sleeve. 7. The conductive adhesive is an elastic synthetic resin adhesive, and the plurality of coaxial cables have a structure that allows elastically changing their relative positions. The semiconductor LSI inspection device according to items 2 to 5. 8. The probe formed at the tip of each of the plurality of core wires constitutes at least three types of wiring: one for power feeding, one for signal input/output, and one for grounding. 1 to 6. 9. The core wire of the coaxial cable is directly electrically and mechanically connected to the pad of the wiring board, and the shield material of the coaxial cable is connected to the grounding member of the wiring board. A semiconductor LSI inspection device according to any one of claims 1 to 4. 10. Any one of claims 1 to 8, wherein the hard metal constituting the probe is tungsten or stainless steel, and the tip of the probe is sharpened by electrolytic polishing. Semiconductor LSI described in
Inspection equipment. 11. The metal sleeve is made of beryllium copper, brass,
Made of nickel silver, copper, or stainless steel, the sleeve is gold-plated, rhodium-plated, or unplated, and is fixed to the core wire by crimping, spot welding, or laser welding. The semiconductor LSI according to any one of claims 4 to 9,
Inspection equipment.