JPH08184612A - Inspection apparatus for semiconductor wafer - Google Patents

Abstract

PURPOSE: To reduce the size and cost of an inspection apparatus by using an inspection card formed of a semiconductor wafer formed of an inspection IC chip and having the same effectiveness as an object to be inspected. CONSTITUTION: An inspection card is formed of a semiconductor wafer having the same material and effectiveness as those of an object to be inspected and formed with many inspecting IC chips 2a. The card also has a plurality of gate circuits 2b for selectively operating the IC chip to be inspected, wirings 4a for a gate circuit control signal, and wirings 4b, 4c for input and output signals. The wirings 4a to 4c are connected to an external inspection circuit 6, the circuit 2b is connected in parallel with wirings 4a to 4c, which extract a control signal S1 , an inspection signal S2 and a response signal S4 . Further, one or a plurality of the chips 2a are connected to the circuit 2b to replace an inspection response signal S3 . Thus, the chips 2a input inspection signal from the circuit 6 to the IC chip to be inspected, and outputs a response signal to the circuit 6. The inspection circuit elements can be easily formed on the card by IC forming technology, so that they can be simplified and reduced in cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection device for inspecting a large number of IC chips to be inspected on a semiconductor wafer.

[0002]

2. Description of the Related Art Generally, an IC is used to inspect an IC chip formed on a semiconductor wafer or a product under manufacturing thereof.
The chip group is checked element by element with an inspection electrode, or a contact is brought into contact with the external electrode group of each IC chip to repeat the inspection. At this time, while moving the semiconductor wafer, each IC chip formed on the wafer is inspected.

[0003]

Therefore, it takes a lot of time to inspect a large number of IC chips on a wafer, and the inspection cost is high.

Furthermore, since processing of electric signals and response signals necessary for inspection depends entirely on external inspection circuits, it has become necessary to detect weak signals and input / output high-frequency signals as in recent years. In the inspection, there are cases where the inspection cannot be performed due to the attenuation and noise due to the circuit on the way.

Recently, there is an increasing demand for performing a burn-in test on an IC package on a bare IC chip. In this burn-in test of the bare IC chip, the IC chip is directly burned in as it is without packaging the IC chip. Input and output must be done.

The electrode pad group of the IC chip is a large number of hundreds of pads with a fine pitch, and the contact group that contacts it is also fine and numerous. Therefore, in order to burn-in at a high temperature while keeping the position of the electrode pad group and the contact group of the IC chip in contact with each other, the contact is not deformed by heat or the contact or
It is necessary that the material holding the C-chip does not undergo thermal deformation. That is, there is a limit to making the contact pitch fine, and there is a problem that the material holding the contact causes thermal expansion or deformation due to high heat in burn-in, and the position of the contact point is displaced, resulting in lack of reliability.

[0007]

As a means for solving the above problems, the present invention targets a semiconductor wafer having a large number of IC chips to be inspected, and has a large number of inspection IC chips. An inspection card is formed by an existing semiconductor wafer, and the inspection IC chip selectively inputs an inspection signal from an external inspection circuit to an inspected IC chip to be inspected and sends a response signal from each inspection IC chip to the external inspection circuit. This is a device for inspecting a semiconductor wafer forming a gate circuit for outputting.

[0008]

The present invention effectively solves the above problems by using an inspection card made of a semiconductor wafer of the same effect in which a circuit element group (inspection IC chip) necessary for stable inspection of a semiconductor wafer to be inspected is formed. It is a thing.

The inspection circuit element for selectively inspecting the IC chip to be inspected on the semiconductor wafer can be easily formed on the inspection card by the IC forming technique, and the size and cost can be reduced.

Since bumps are formed on the electrode pads of the IC chip on the wafer, it is possible to make the inspection card with high accuracy and to make an inspection card with the same material as the inspection object, so there is no displacement of the contact points due to heat such as burn-in.

The above-described inspection apparatus can inspect a large number of IC chips formed on a semiconductor wafer in an extremely efficient and stable manner, and contributes to reduction in inspection cost.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention has a large number of ICs to be inspected as shown in FIG.
The semiconductor wafer 1 having the chip 1a is an inspection target.

In FIG. 2, an IC chip 1a to be inspected formed on the semiconductor wafer 1 is pasted on a flexible plastic sheet 1c in a separated state. The plastic sheet 1c is a thermoplastic film or a plastic film having an adhesive layer on the surface. The semiconductor wafer 1 to be inspected means one in the state shown in FIG. 1 or FIG.

On the other hand, the inspection card 2 is formed by a semiconductor wafer on which a large number of inspection IC chips 2a are formed.

Therefore, the card 2 is manufactured based on the known semiconductor wafer forming technique, and has the same material and the same effect as the semiconductor wafer 1 to be inspected.

In FIG. 3, the inspection IC chip 2a and the gate circuit 3 are shown separately to facilitate understanding, but the inspection card 2, that is, a plurality of inspection IC chips formed on the semiconductor wafer. 2a is an IC to be inspected to be inspected
A plurality of gate circuits 2b for selectively operating the chip 1a
(Switching circuit group) and bumps 5 group contacting the electrode pad 1b group of the IC chip 1a to be inspected.

Further, as shown in FIG. 3, the inspection card 2 further includes gate circuit control signal wiring 4a for controlling the opening / closing of each gate circuit 2b, and each inspection IC via each gate circuit 2b.
An input signal wiring 4b for supplying an inspection signal and power to the chip 2a and an output signal wiring 4c for extracting a response signal from each IC chip 1a to be inspected and the inspection IC chip 2a via each gate circuit 3 are provided. However, the wirings 4 a, 4 b, 4 c are connected to the external inspection circuit 6.

The gate circuit control signal wiring 4a is connected in parallel with each gate circuit 2b so that the control signal S ₁ can be supplied individually to each gate circuit 2b, and the input signal wiring is also provided. Each gate circuit 2b is connected in parallel to the wiring 4b so that the inspection signal S ₂ can be individually supplied to each gate circuit 2b, and the output signal wiring 4c is individually connected to each gate circuit 2b. Response signal S ₄
So that each gate circuit 2b can be taken out from the wiring 4c.
Are connected in parallel.

Further, one or a plurality of units of inspection IC chips 2a are connected to a certain unit gate circuit 2b so that each of the gate circuits 2b and each of the inspection IC chips 2a can exchange the inspection / response signal S ₃ individually. In addition, the inspection IC chip 2a of another unit or a plurality of units is provided for the other unit gate circuit 2b.
Is connected.

All the above-mentioned connections between the respective wirings 4a, 4b, 4c and the gate circuit 2b and the inspection IC chip 2a are formed by a known wafer manufacturing technique for forming IC chips on a semiconductor wafer.

On the other hand, bumps 5 which come into contact with the electrode pads 1b of the IC chip 1a to be inspected are formed on the surface of the inspection IC chip 2a on the semiconductor wafer forming the inspection card 2, and the gate circuit 2b has the bumps 5b. Connected to 5.

The inspection IC chip 2a has the bumps 5
Signals are exchanged via the contact between the electrode pad 1b of the IC chip 1a to be inspected.

The bump 5 group is formed of, for example, minute plastic balls 5a as shown in FIG.
This plastic ball 5a is an elastic body having a metal plating coat 5'on its surface. Since it is a plastic, it can be manufactured to have a very small diameter, and the proper elasticity required for pressure contact can be secured.

As another example, the bump 5 is formed by a metal ring 5b as shown in FIG. 7, and the circumferential surface of the metal ring 5b is used as a pressure contact point.

As still another example, the bump 5 is formed by wire bonding 5c as shown in FIG.

Each of the plastic ball 5a and the metal ring 5b has an inspection IC chip 2 at one point on its circumferential surface.
It is adhered to the electrode pad 2c on the surface of a, and one point on the opposite side is used as a pressure contact point with the electrode pad 1b.

The wire bonding 5c is formed by melting and separating the tip of a thin wire on the surface of the electrode pad, and the sharp tip is formed on the electrode pad 1b.
It is the point of pressure contact with.

As shown in FIG. 4, the semiconductor wafer 1 to be inspected is placed on the inner bottom surface of the accommodation chamber 8 formed on the upper surface of the inspection stage 7. The stage 7 is heated by the heater 11 as needed.

On the other hand, the inspection card 2 made of a semiconductor wafer has bumps 5 of which the electrode pads 1 of the IC chip 1a to be inspected.
The semiconductor wafer 1 is superposed on the semiconductor wafer 1 while being aligned so as to contact with b.

The inspection card 2 covers the accommodation chamber 8 in which the semiconductor wafer 1 is accommodated, and when the gas in the accommodation chamber 8 is vacuumed through the suction port 9 provided on the stage 7, the inspection card 2 is inspected for the semiconductor wafer 1. Bump 5 pressed against the surface
A pressure contact between the group and the electrode pad 1b is obtained.

The stage 7 is provided with an elastic sealing 10 for supporting the inspection card 2 around the accommodation chamber 8, that is, around the semiconductor wafer 1. The inspection card 2 is pressed against the elastic sealing 10 by the vacuum to keep airtightness. The state of pressure contact between the bump group 5 and the electrode pad 1b is protected.

FIG. 5 shows the semiconductor wafer 1 and the inspection card 2 described above.
3 is an enlarged view of the contact portion of the above, and signals are exchanged through contact between the two bump groups 5 and the electrode pad 1b.

Thus, in the state shown in FIGS. 4 and 3, one of the groups of gate circuits 2b is selectively opened by the control signal from the control signal wiring 4a (gate-on state), whereby the input signal wiring 4b. Signal flows into the inspection IC chip 2a corresponding to the gate circuit 2b, and the inspection IC chip 2a
The IC chip 1a to be inspected, which is brought into contact with a, is energized and an inspection / response signal is output. This inspection / response signal is introduced into the output signal wiring 4c via the gate circuit 2b whose gate is turned on, and taken into the external inspection circuit 6.

While the above inspection is being performed, all the other gate circuits 2b are placed in the closed state (gate off state) to prepare for the next command.

That is, while a plurality of IC chips 1a to be inspected are selected from the outside through the control signal wiring 4a, a plurality of IC chips 1a to be inspected of the semiconductor wafer to be inspected are successively electrically inspected. Therefore, many IC chips 1a to be inspected on the semiconductor wafer can be inspected at high speed without any mechanical operation.

On the other hand, in the burn-in test, all ICs to be inspected
Since it is necessary to keep the chip 1a in the operating state, it is assumed that the gate circuit 2b connects the signal of the input signal wiring 4a necessary for the operation of the IC chip to be inspected to the bump 5 group in the normal state.

As an example, on the inspection card 2 or the inspection semiconductor wafer, an amplifier circuit for a weak signal which is a part of the external inspection circuit 8 or an IC chip for an inspection judgment circuit for judging the quality of the IC chip to be inspected Can be formed. This embodiment is effective as a countermeasure against this noise when the line length connected to the external inspection circuit 6 is long and causes a noise problem.

Further, according to the present invention, the inspection target I
The case where the above-mentioned inspection is performed by directly contacting the electrode pad 1b of the C chip 1a and the electrode pad 2b of the inspection IC chip 2a is included.

Further, according to the present invention, the above-mentioned inspection can be performed without providing the bump 5 with the conductive elastomer interposed between the both 1a and 2a.

[0040]

The inspection card composed of the semiconductor wafer described above can be easily formed by the conventional semiconductor wafer forming technique for its inspection circuit elements, wiring, and connection, and the inspection device can be downsized and the cost can be reduced.

Further, since the semiconductor wafer to be inspected can be manufactured with the same material as that of the semiconductor wafer to be inspected, it is possible to effectively prevent the displacement of the contact portion due to the thermal expansion due to the heat at the time of burn-in inspection, and to greatly improve the reliability of inspection. You can

Further, by providing bumps on the electrode pads of the IC chip to be inspected formed by the wafer manufacturing technique, it is possible to improve the accuracy and cope with a fine pitch. That is, it is possible to overcome the manufacturing positional accuracy and cost problems when the conventional probers (contactors) are arranged on the substrate at a fine pitch.

According to the present invention, a large number of IC chips formed on a semiconductor wafer can be inspected efficiently and at low cost without any mechanical operation, and it is possible to provide an inspection request in a bare chip state before packaging or supply a bare chip. It can properly respond to the inspection problems involved.

[Brief description of drawings]

FIG. 1 is a plan view of an inspection card or a semiconductor wafer to be inspected.

FIG. 2 is a side view of the same.

FIG. 3 is a plan view illustrating circuit elements, wirings, and signal flows formed on an inspection card made of a semiconductor wafer.

FIG. 4 is a cross-sectional view of an inspection device inspecting a semiconductor wafer to be inspected using the inspection card.

FIG. 5 is an enlarged side view showing a contact state between an inspection card and a semiconductor wafer to be inspected.

FIG. 6 is an enlarged view showing an example of bumps attached to the surface of the inspection IC chip on the inspection card.

FIG. 7 is an enlarged view showing another example of the bump.

FIG. 8 is an enlarged view showing still another example of the bump.

[Explanation of symbols]

 1 semiconductor wafer to be inspected 1a IC chip to be inspected on the semiconductor wafer 1b Electrode pad of the IC chip to be inspected 2 Inspection card 2a consisting of a semiconductor wafer Inspection IC chip on the above inspection card 2b Gate circuit on the inspection card 4a Inspection Wiring for control signal on card 4b Wiring for same input signal 4c Wiring for same output signal 5 Bump attached to inspection IC chip

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H01L 21/66 F

Claims (2)

[Claims] 1. A semiconductor wafer having a large number of IC chips to be inspected is inspected, and an inspection card is formed by the semiconductor wafer having a large number of inspection IC chips, and the inspection IC chips are inspected. A semiconductor wafer having a gate circuit for selectively inputting an inspection signal from an external inspection circuit to an IC chip to be inspected and outputting a response signal from each inspection IC chip to the external inspection circuit. Inspection device. 2. The semiconductor wafer inspection apparatus according to claim 1, wherein bumps are formed on each of the inspection IC chips so as to come into contact with the electrode pads of the IC chip to be inspected.