JPH01261840A - Measuring method - Google Patents

Abstract

PURPOSE:To make it possible to perform highly accurate position alignment at a high speed, in position alignment of the electrode pads of a body to be measured and a probe, by moving a mounting stage, performing the coarse position alignment of a probe card, moving the probe card, and performing fine alignment. CONSTITUTION:The total inspection of an IC chip 13 is performed. At this time, a probe 16 matching an electrode pad 15 is brought into contact with the bonding electrode pad 15 which is formed at the periphery of the IC chip 13. A probe card 14 is fixed. A mounting stage is controlled and moved in the X and Y directions for every interval of the IC chip sequentially with 5mum as one unit. Exclusive measuring electrode pads 18 are formed at the periphery of each circuit part 17. In order to bring the probe matching the electrode pad 18 into contact with the electrode pad 18, a mounting table 10 is controlled and moved in the X and Y directions at the unit of 5mum, since the exclusive measuring electrode pad 18 is very minute. At the same time, the probe card 14 is controlled and moved in the X and Y directions with 1mum as one unit.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a measuring method.

(Prior Art) In recent years, with innovations in IC chip manufacturing technology, multifunctional IC chips with higher integration and speed have been produced.

For example, such an IC chip has an MPU, R
A wide variety of circuit units such as AM, ROM, ALU, TTL, etc. are connected by conductive patterns. Here, this I
It is necessary to measure the electrical characteristics of the C-chip not only for the entire circuit, but also for each circuit section. For this reason, the IC chip is provided with, for example, a 70-100-square electrode pad for bonding on the periphery of the IC chip, and a 20-30 μs square electrode pad for measurement only on the periphery of each circuit portion. When measuring the electrical characteristics of such IC chips, a semiconductor wafer on which a large number of IC chips have been formed is placed on a movable mounting table, and this mounting table is sequentially moved horizontally at each chip interval, and each time the semiconductor wafer is moved vertically. It was necessary to go up and down, bring the probe needles of the probe card into contact with the electrode pads for bonding and the electrode pads dedicated to measurement, connect the tester and the IC chip, and perform measurements.

(The problem that the invention attempts to solve) However, when measuring the above IC chip.

The mounting table is normally controlled in units of 5 m due to mechanical accuracy due to movement speed and weight, so it is
00-square bonding electrode pad with a tip of 50
There is no problem in making contact with the probe needle of a probe card of about μs, but it is about 20 to 30 μs. To bring a probe needle with a tip of about 5 to 10 μs into contact with an electrode pad dedicated to measuring corners, moving the mounting table in steps of 5 IJ1 seconds makes it difficult to align the pad and needle, making it difficult to make accurate contact. There was a problem in that the circuit part could not be measured.

This invention was made in response to the above points.

The purpose of the present invention is to provide a measurement method that is compatible with measurement-specific electrode pads that are smaller than bonding electrode pads, and that enables highly accurate positioning to be performed at high speed.

[Structure of the invention]

(Means for Solving Problem 11) The present invention provides a measurement method in which electrode pads of an object to be measured placed on a mounting table and probe needles of a probe card are aligned and brought into contact for measurement. The method is characterized in that the mounting table is moved to perform rough positioning of the probe card, and the probe card is moved to perform fine positioning.

(Effect) The precision is improved by moving the mounting table to perform coarse positioning of the probe card, and by moving the probe card to perform fine positioning. This makes it possible to perform high-speed alignment with high accuracy and accurate measurements.

In particular, since the probe card is considerably lighter than the mounting table, fine positioning can be easily performed.

(Example) Next, an example in which the measurement method of the present invention is applied to measurement of a semiconductor wafer using a probe device will be described with reference to the drawings.

First, the configuration of the probe device will be explained. As shown in FIGS. 1 and 2, the storage section (1) mainly stores the object to be measured, such as a semiconductor wafer (2) on which a large number of IC chips are formed, and has a preliminary alignment mechanism. and a measuring section (2) that measures the electrical characteristics of the object to be measured.

The storage section (2) is equipped with a plurality of, for example, two systems of mounting tables (2) on which objects to be measured (e.g., semiconductor wafers (2) can be placed in cassettes capable of loading, for example, 25 wafers (25) at predetermined intervals in the board thickness direction). . Each of these mounting tables (■) is vertically movable by a drive mechanism, such as a ball screw (■) connected to a motor (2), and is moved to a desired unloading/loading position when a semiconductor wafer (■) is transported or loaded from a cassette (A). It is possible to install semiconductor wafers ■.

A transport arm (2) is provided for carrying in and out one by one the semiconductor wafers ω housed in the cassette (A). This transfer arm is provided on a transfer stage (not shown), for example, a uniaxial movement mechanism using a linear guide, a ball screw, and a motor. A preliminary alignment stage (2) is provided to perform preliminary alignment of the wafer (2) transferred by this transfer arm (2). This preliminary alignment stage (2) is provided with a vacuum suction mechanism (not shown) so as to fix the semiconductor wafer (2) on the mounting surface. In addition, a drive mechanism (17) (not shown), for example, equipped with a 1-axis movement mechanism using a ball screw and a motor and a rotation mechanism using a timing belt and a motor, allows the preliminary alignment stage (1) to be moved up and down in the vertical direction and rotated. is provided. Further, a light emitting/light receiving sensor (not shown) for preliminary alignment is provided near the preliminary alignment stage (1).

The storage section (2) is configured as described above, and the measurement section (2) will be explained next.

The measurement section (2) is connected to the left or right side of the storage section (2) configured as described above, and is configured so that the wafer (2) transferred from the storage section (2) is measured by the measurement section (2). This measurement part■
is provided with a mounting table (10) on which the semiconductor wafer (2) is placed, and a vacuum suction mechanism (not shown) is provided to fix the semiconductor wafer (2) on the mounting surface. In addition, the mounting table (10) is controlled in units of 50 mm due to high speed, weight, etc., and is movable in the X direction, Y direction, Z direction (vertical direction), and θ direction (rotational direction). The stage (11) is provided, for example, in a three-axis moving mechanism (not shown) using a near guide, a ball screw, and a motor, respectively, and a rotation mechanism (not shown) using a motor. Within the movement range of the mounting table (10) by the movement stage (11), there is a CO
An alignment section (12) is provided that includes a pattern recognition mechanism using a D camera, a laser recognition mechanism, a capacitive sensor that recognizes installation conditions such as changes in the height of the semiconductor wafer (2), and the like. Moreover, above the predetermined position of the mounting table (lO).

A probe card (14) for connecting an IC chip (13) formed on a semiconductor wafer (1) and a tester (not shown).
) is provided. This probe card (14) has a tip diameter corresponding to, for example, 70 to 100 square electrode pads (15) for bonding provided on the periphery of the IC chip (13), as shown in FIG. For example, 50μ
s probe needles (16) are arranged or I
Each circuit section (17) of the C chip (13), for example, MPU, R
For example, 20 to 30. Corresponding to the corner electrode pad (18) arrangement, a probe needle (with a tip diameter of, for example, 5 to 10p) is used.
16) are arranged, or probe needles (16) sharing these probe needles are arranged. And each of the above-mentioned electrode pads (15) and (18).

Electrical measurements can be made by touching each probe needle (16). Also, during this contact, the corresponding probe needle (
16) is possible, but
For the extremely small electrode pad (18) dedicated to measurement.

The positioning for bringing the corresponding ultra-fine probe needle (16) into contact may not be performed accurately because the mounting table (10) is controlled every 5 μs. Corresponding to this, the probe card (14) is configured to be slightly movable as shown in FIG. This fine movement mechanism (19) is installed on a base member (20) which is the upper surface of the measuring section (2), which has a highly accurate flat surface. A guide surface (21) is placed at a predetermined position on this base member (20).
) with a suction plate (22) attached to the guide rail (23
) to be fixed. The guide surface of this guide rail (23) (
Opposed to the L-shaped slider (21), two systems of air bearings (24) and a magnet (25) are attached.
26) is provided so as to be slidable in the Y direction (27). An air bearing (28) is provided on the lower surface of the above-mentioned L-shaped slider (26), facing the base member (20).
A system is established. In addition, the above-mentioned cursive-shaped slider (2
The X plane of 6) is a rectangular slider (29) in the X direction (29).
30) is the guide surface (31). Here, a suction plate (32) is attached to this guide surface (31), and a magnet (33) is attached to the surface of the slider (30) facing this suction plate (32).

Further, the slider (30) is provided with two systems of air bearings (34) facing the guide surface (31).
In addition, an air bearing (3
5), for example, three systems are provided facing the base member (20).

The slider (30) as described above is engaged with a drive motor (not shown) in the X direction (29) and the Y direction (
27). In addition, in order to control this movement for each p, the adjacent two of the slider (30)
A laser scale (36) is provided on each side, and a laser length measuring device (36) is provided opposite each laser scale (36).
37) is provided. The probe card (14) described above is attached to the lower surface of the slider (30) whose movement can be controlled every 1 μs so as to protrude from an opening (not shown) provided in the base member (20). ing.

Then, a conveyance means for conveying the semiconductor wafer (1) from the preliminary alignment stage 0) of the storage section (2) to the mounting table (10) of the measuring section (2), for example, engages with a rotating motor (not shown), and the mounting table (10) A rotating arm (38) is provided that is installed corresponding to the height position. This rotary arm (38) has a semicircular notch formed on its side at its tip, and is configured to vacuum-adsorb the semiconductor wafer (3) at the tip.

Furthermore, this rotating arm (38) is located at the measuring section (■).
Items of the same shape for loading and unloading are installed vertically at a predetermined interval.

The operation and setting of the probe device consisting of the above-mentioned measuring sections (1) and storage section (2) are controlled by a control section (not shown).

Next, a method for measuring an object to be measured, such as a semiconductor wafer (2), using the above-mentioned probe device will be explained.

First, a cassette containing, for example, 25 semiconductor wafers (2) is carried onto each cassette mounting table (2) using a robot hand or manually and placed therein. Then, the cassette mounting table (2) is raised and lowered to place the first wafer ω to be measured at a predetermined height position. Here, the transfer arm (2) is slid to place the wafer (2) on the preliminary alignment stage (2). After vacuum suctioning the wafer (2) on this preliminary alignment stage (2), the wafer (2) is rotated and one light emitting/light receiving sensor is used to center the wafer (2) and perform preliminary alignment based on the orientation flat. After this, the wafer ■ is moved to the measuring section ■ by the rotating arm (38).
The sample is transferred to a mounting table (lO) and vacuum-adsorbed. Then, the mounting table (10) is moved to the alignment section (12) by the moving stage (11), and alignment is performed accurately based on the pattern such as the scribe line of the wafer (2). After this alignment, place the mounting table (10) on the probe card (14).
) Move the probe card to the opposite installation position, rotate the probe card in the θ direction, align it with the X/Y direction of the measurement stage, and raise it at a predetermined position.

Each probe needle (16) of the probe card (14) is brought into contact with the electrode pad (15) (1g) of the IC chip (13) formed on the wafer (2), and a tester (not shown) is used to test the IC chip (13) and Inspection and measurement of the electrical characteristics of each circuit section (17) are performed. Here, in this contact inspection measurement, if the entire IC chip (13) is inspected,
Since the probe needle (16) corresponding to the electrode pad (15) can be brought into contact with the bonding electrode pad (15) formed on the periphery of the C-chip (13), the probe card (14) can be fixed. , by sequentially moving the mounting table (10) in the X-Y direction at intervals of IC chips (13) in units of 5 μm, and forming on the periphery of each circuit section (17). In order to bring the probe needle (16) corresponding to the measurement electrode pad (18) into contact with the measurement electrode pad (18), since the measurement electrode pad (18) is ultra-fine, the mounting table (10) must be moved. At the same time, the probe card (14) is controlled and moved in the X-Y direction in units of 54, and at the same time, the probe card (14) is controlled and moved in the X-Y direction in units of 1 um. The movement of this probe card (14) is as follows:
First, for example, 2 to 3 kgf/al of air is applied to each air bearing (28) (35) provided on the slider (26) for the Y direction (27) and the slider (30) for the X direction (29). Supply approximately .2ffi/win. This creates an air flow film between each slider (26) (30) and the base member (20) and separates them. At the same time, the guide rail (23) for the Y direction (27)
) and the air bearing (24) of the slider (26) facing the guide surface (21) of the slider (26) in the X direction (
slider (3) facing the guide surface (31) for
Compressed air similar to the above is supplied to each of the air bearings (34) of No. 0). This allows each guide surface (21) (31)
An air flow film is generated between the sliders (26) and (30), and one mechanical friction area is eliminated. In this state, drive each motor (not shown) selectively or simultaneously,
Slide each slider (26) (3o). That is, the probe card (14) is attached to the slider (30).
).

The above operation allows the probe card (14) to smoothly slide in the desired direction of the X-Y directions (29) and (27). For this movement, the slider (30) is provided with two laser scales (36), one for the X direction and one for the Y direction, and each of the scales (36)
The amount of movement is detected from a laser length measuring device (37) facing the
The amount of movement is controlled at about 1 mi by a control unit (not shown).

As described above, the mounting table (10) is moved at high speed for rough alignment, and the probe card (14) is moved finely for fine alignment. Then, after accurate alignment,
The mounting table (10) is raised to bring the measurement electrode pad (18) of the IC chip (13) into contact with the probe needle (16), and an electrical measurement is performed using a tester (not shown).

Such measurement operations are repeated to measure the IC chip (13) formed on the wafer (2) and each circuit section (17) formed within the IC chip (13).

In the above embodiment, fine alignment is performed.

Although the electrode pad is used for measurement only, the electrode pad for bonding is, for example, 50. This may be carried out for objects formed below a corner, and the positioning may be carried out only by moving the probe card, without moving the mounting table to carry out rough positioning.

As described above, according to this embodiment, by finely moving the probe card and accurately performing fine positioning, accurate measurements can be made and yields can be improved.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the probe device for explaining the method of the present invention, Fig. 2 is a top view of Fig. 1, Fig. 3 is a block diagram of the fine movement mechanism of Fig. 1, and Fig. 4 is a block diagram of the IC which is the object to be measured in the figure
Enlarged view of chip

Claims (1)

[Claims] In a measurement method in which the electrode pad of the object to be measured placed on a mounting table and the probe needle of a probe card are aligned and brought into contact for measurement, the above-mentioned positioning means moves the above-mentioned mounting table to roughly align the probe card. A measuring method characterized by performing fine positioning by moving the probe card.