JPH01248632A - Measuring method - Google Patents

Abstract

PURPOSE:To perform easy and effective conveyance of a body to be measured by controlling the height position of a preliminary alignment mechanism, conveying the body to be measured to measuring units by conveying means, and measuring it. CONSTITUTION:After a first wafer 1 is first preliminarily aligned, it is conveyed from a preliminary alignment stage 16, for example, to the placing part 18 of a left measuring unit 3 by means of a load rotating arm 23. The conveyance is conducted by mounting a rotary arm 23 under the first wafer 1, moving down the stage 16 by a predetermined distance, vacuum-attracting it by the end of the arm 23, and rotating it on the part 18. Then, after the wafer 1 is aligned, a predetermined measuring operation is started. When the mounting height of the arm 23 of the unit 3 is different from that of a right measuring part 3, the moving down distance of the stage 16 is stored in advance corresponding to the height position of the arm 23. Accordingly, a conveying operation can be smoothly performed. Thus, the body to be measured can be easily and effectively conveyed.

Description

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

(Conventional technology) Recent technical innovations in semiconductor manufacturing processes have led to higher integration and higher quality of IC chips, and the demand for IC chips for specific applications has increased. is increasing. Due to this, there is a need for a measuring device for measuring the electrical characteristics of an IC chip. However, when measuring high-quality IC chips, due to the high degree of difficulty and the increase in the number of measurement items,
The time required to measure a single wafer on which a large number of IC chips are formed continues to increase. For this reason, conventional measurement equipment has been equipped with a measuring section and a wafer storage section with a preliminary alignment mechanism, which reduces the operating rate of the wafer storage section mechanism and requires a large amount of floor space for installing the equipment. The problem was that it was large. Examples of solutions to this problem include JP-A-60-49642 and JP-A-61-168.
No. 236, Japanese Unexamined Patent Publication No. 62-35212, etc., disclose a system in which objects to be measured are supplied from one storage section to a plurality of measurement sections, and in order to shorten the alignment time, Those equipped with a stage mechanism are disclosed in, for example, Japanese Patent Laid-Open Nos. 57-115843 and 61-220349.

(Problems to be Solved by the Invention) However, the above-mentioned Japanese Patent Application Laid-open No. 168236/1983.

In Japanese Patent Application Laid-open No. 62-35212, a single arm transport means carries out the transport from the storage section to the preliminary alignment stage and from this preliminary alignment stage to each stage of each measurement section, so that the object to be measured is It takes time to transport the equipment, which reduces the operating efficiency of the equipment itself. Furthermore, as in Japanese Patent Application Laid-Open No. 60-49642, when measurements are performed by distributing the preliminary alignment position to a plurality of measurement sections, each mounting table of each measurement section and the preliminary alignment position are independent. There has been a problem in that the height positions of each mounting table and the preliminary alignment position are misaligned due to errors that occur during the manufacturing stage, and adjustment is extremely difficult.

The present invention has been made in response to the above-mentioned problems, and provides a measurement method that provides the effect of easily and reliably transporting the object to be measured from the preliminary alignment position to each mounting table of each measurement section. be.

[Structure of the invention]

(Means for Solving the Problems) This invention preliminarily aligns the object to be measured housed in a storage container, and transports the object to be measured from the preliminary alignment g & structure by each conveying means of at least two measurement units. The measuring method is characterized in that the height position of the preliminary alignment mechanism is controlled, and the object to be measured is transported to each measurement section by each of the transport means for measurement.

(Effects) By controlling the height position of the preliminary alignment mechanism and transporting the object to be measured to each measurement section by each transport means for measurement, the object to be measured can be transported easily and reliably. or,
Since there is no need to perform difficult height alignment work, it is possible to shorten the time required for one work, and the effect of improving operating time can be obtained.

(Embodiment) Next, an embodiment in which the method of the present invention is applied to measurement with a probe device that transports objects to be measured from one storage section to two measurement sections will be described with reference to the drawings.

First, the configuration of the probe device will be explained. This probe device mainly stores the object to be measured, for example, a semiconductor wafer (2) on which a large number of IC chips are formed, a storage section (2) having a preliminary alignment mechanism, and an electric field of the object to be measured (3). It consists of a measuring section (2) that measures physical characteristics.

As shown in FIG.
There are two systems of mounting tables 0 on which cassettes (A) capable of loading five cassettes can be installed. Each of these mounting tables (C) is vertically movable in the direction of the arrow (■) by a drive mechanism, for example, a ball screw (■) connected to a motor 0. A desired semiconductor wafer (2) can be placed at the loading position.

As shown in Figure 4, below the cassette (A) mounting position in the mounting table ■, there is a transfer mechanism ■, for example, a handle (1o) that can be slid horizontally from the mounting table ■, and it fits into the mounting table 0. 11)
is provided. On this drawer 11), a holder (12) is provided which can hold a wafer for calibration of the measuring section, a dummy wafer whose surface is coated with aluminum for use during auto-setup, and the like. This holder (12) has recesses that match the external shape of the wafer to be processed in stages for each wafer size, and is removably supported by a rectangular plate with a U-shaped notch on one side. ing. That is, by sliding the calibration wafer or dummy wafer toward the front side of the storage section ■ in the direction of the arrow (13), place the calibration wafer or dummy wafer in the holder (12).
It can be taken out of the storage compartment ■ while being held in place. Here, a transfer arm (1
4) is provided. The transport arm (14) is provided on a transport stage (15), for example, a uniaxial movement mechanism (not shown) using a linear guide, a ball screw, and a motor. A preliminary alignment stage (
16) is provided. This preliminary alignment stage (16) is provided with a vacuum suction mechanism (not shown) so as to fix the semiconductor wafer (1) on the mounting surface. In addition, the preliminary alignment stage (16) is raised and lowered in the vertical direction, and θ
A drive mechanism (17), for example, a one-axis movement mechanism using a ball screw and a motor, and a rotation mechanism using a timing belt and a motor is provided so as to be rotatable. Further, a light emission/light reception sensor (not shown) for preliminary alignment is provided near the preliminary alignment stage (16).

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

As shown in Figs. 1 and 2, the measuring section (2) is connected to the left and right sides of the storage section (2) configured as described above.
) are distributed to the left and right measuring sections (30) for measurement. Each measuring section (30)
is provided with a mounting table (18) 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, each mounting table (18) is equipped with a moving stage (19), such as a linear guide, a ball screw, and a motor, so that it can move in the X direction, Y direction, Z direction (vertical direction), and θ direction (rotational direction). It is provided in the three-axis movement mechanism (not shown) used and the rotation mechanism (not shown) driven by a motor. The above moving stage (
Within the movement range of the mounting table (18) according to 19), there is a pattern recognition mechanism using a COD camera for positioning the pattern formed on the semiconductor wafer (2) as a reference, or
An alignment section (20) is provided that includes a laser recognition mechanism and a capacitive sensor that recognizes installation conditions such as changes in the height of the semiconductor wafer (2). Further, a probe card (21) is provided above a predetermined position of the mounting table (18) for connecting the IC chip formed on the semiconductor wafer (2) to a tester (not shown). This probe card (
21), probe needles (22) are arranged corresponding to the electrode pad arrangement of the IC chip, and electrical measurements can be made by connecting each of the electrode pads and each probe needle (22). ing. Then, the semiconductor wafer (G) is mounted on each mounting table (18) of each measuring section (2) by means of a transport means, for example, engaged with a rotating motor (not shown), for transporting the semiconductor wafer (G) from the preliminary alignment stage (16) of the storage section (2). Stand (1
Rotating arm (23) installed corresponding to the height position of
) is provided. This rotary arm (23) has a semicircular notch formed on its side at its tip, and is configured to vacuum-adsorb the semiconductor wafer (2) at the tip. Furthermore, this rotating arm (23) is connected to each measuring section (30).
In this case, devices of the same shape for loading and unloading are installed vertically at a predetermined interval. Here, a printer (24) for displaying, for example, printing out the electrical measurement results of each IC chip for each semiconductor wafer (2) in the above-mentioned measuring section (2) is provided on the front side of each measuring section (2).

The probe device consisting of each measuring section (3) and storage section (2) as described above is controlled in operation and setting by a control section (not shown).

Here, before measuring the object to be measured, such as a semiconductor wafer (2), using the probe device, the installation height of each rotary arm (23) of each measurement unit (2) and the height of the preliminary alignment stage (16) are adjusted in advance. , remember. That is,
If each measurement section (■) and storage section (■) are configured in independent housings, each mounting table (one
8) and the height position of each mounting table (18), there will be an error in the installation height of the rotating arm (23) that transfers the wafer.In order to eliminate this error, the wafer receiver is The height positions of each rotating arm (23) and preliminary alignment stage (16) are adjusted in advance. For example, when transferring a pre-aligned wafer ■ from the pre-alignment stage (16) to the rotating arm (23),
As shown in Fig. 5, the rotary arm (23) is rotated around the axis (25) in the direction of the arrow (26) and placed below the wafer ■ placed on the preliminary alignment stage (16)'b2. . Next, the vacuum suction for fixing the wafer is released, and the preliminary alignment stage (16) is moved by the drive mechanism (
17), the rotating arm (23)
Vacuum adsorb the wafer ■ at the tip of the wafer. When receiving and transferring the wafer (2) in this way, the height position of each rotary arm (23) of each measurement unit (2) may be shifted by (L), for example, as shown in FIG. be. In this case, for example, when the right-hand rotation arm (23) is installed at a position (L) lower than the left-hand rotation arm (23), the receiver determines the amount of descent of the preliminary alignment stage (16) in advance at the time of handover. It is set and memorized so that the right rotation arm (23) is lowered by (L) more than the left rotation arm (23).

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, for example, 25 wafers ■ of the same type or different types are
The loaded cassettes (A) are carried into each cassette mounting table (■) and installed. Also, the wafer for calibrating the method for determining the measurement results has already been placed in the transfer mechanism (2) provided on the mounting table (2).

That is, by pulling the handle (10) on the drawer 11) that can be pulled out by fitting with the mounting table (1), the drawer 11) is pulled out in the direction of the arrow (13), and the removable holder (12) on the drawer 11) is removed. A calibration wafer is placed in the recess of the removed holder (12). After this, the holder (1
2) Pull it out 11) Put it back on top and pull it out 11)
Slide it into place. Similarly,
Other calibration wafers and dummy wafers whose surfaces are coated with aluminum or the like to be used during auto-set-up are installed in the transfer mechanism (2) of the other mounting table (2).

The above-mentioned installed calibration wafers are used at a time when a specific number of wafers is programmed in advance in a control unit (not shown).

It is used to recognize whether the functions of each measuring section (■) are working properly at a specified point in time or when recovering from a failure. For example, in this embodiment, the processing is performed in units of cassettes (A). That is, before measuring the semiconductor wafer (2), the calibration wafer is measured by each measurement unit (2).

In this operation, first, the mounting table (2) is raised and lowered in the direction of the arrow (2), and the transfer mechanism (9) on which the calibration wafer is installed is placed at a predetermined height position. Here, the transport arm (14) is slid by the transport stage (15) and the holder (12)
The calibration wafer is inserted into the U-shaped notch, the mounting table (1) is lowered by a predetermined amount, and the calibration wafer is vacuum-adsorbed at the tip of the transfer arm (14). Then, the transfer arm (14) is slid and placed on the preliminary alignment stage (16). On this preliminary alignment stage (16), the calibration wafer is vacuum suctioned, and then the calibration wafer is rotated, and preliminary alignment is performed using the light emitting/light receiving sensor as a reference for centering the wafer and orientation flat. Next, for example, rotate the loading rotary arm (23) of the left measuring section ■ and place it below the calibration wafer, lower the preliminary alignment stage (16), and place the calibration arm Place the wafer. Then, the rotating arm (23) is rotated to place the calibration wafer on the mounting table (18) of the left measuring section (2). Next, the mounting table (
18), and the alignment unit (20) accurately aligns the wafer with reference to the scribe line, etc., and then raises the mounting table (18) at a predetermined position to align the IC chips formed on the calibration wafer. 1 by touching each probe needle (22) of the probe card (21) to the electrode pad.
The electrical characteristics of the IC chip are tested using a tester (not shown). Here, since the calibration wafer was previously used as an inspection and measurement unit, the results at that time and the current results are compared to determine whether there is a difference. As a result of the judgment, if they are the same, the left measuring section (2) is recognized as normal, and if they are different, then a countermeasure will be taken. Furthermore, the same measurement operation is performed for the right measurement section (2). The measurement results of the calibration wafer in the right measurement section (2) are compared with the measurement results in the left measurement section (2) to determine whether there is any machine difference between the two.

As mentioned above, use the calibration wafer to determine whether the left and right measuring parts ■ are normal, and if they are normal, measure the semiconductor wafer ■ stored in the cassette (A), which is the object to be measured.
Displayed on an alarm mechanism (not shown).

To measure the semiconductor wafer (2), first, the first wafer is pre-aligned and then transported from the preliminary alignment stage (16) to the mounting table (18) of the left measuring section (2), for example, by the loading rotary arm (23). In this transfer, the rotary arm (23) is installed below the first wafer α, the preliminary alignment stage (16) is lowered by a predetermined amount, and the first wafer ω is placed at the tip of the rotary arm (23). vacuum adsorption,
It is rotated and conveyed onto the mounting table (18).

Thereafter, after aligning the first wafer (2), a predetermined measurement operation is started. In addition, after the first wafer ■ is transported by the loading rotating arm (23), the second wafer ■ is pre-aligned, and the measuring section opposite to the measuring section ■ that measures the first wafer ■ is moved. (2) That is, it is transported to the mounting table (18) of the right measuring section (2) by the loading rotary arm (23) provided in the measuring section (2). At this time, the rotating arm (23
) is different from the installation height of the rotating arm (23) of the right measuring section ■, use the preliminary alignment stage (16).
Since the amount of descent of each rotary arm (23) is stored in advance in correspondence with the height position of each rotary arm (23), the conveyance operation can be carried out smoothly.

Then, the second wafer (1) is measured using the right measuring section (2).

Furthermore, after transporting the second wafer ■, the third wafer ■ is placed on standby in the loading rotary arm (23) of the right measuring section ■, and in the same way, the fourth wafer ■ is transferred to the right measuring section ■. The rotating arm (23) for loading is placed on standby.

Next, upon completion of the measurement of the first wafer ■, the first wafer α) is unloaded using the unloading rotating arm (23), and the waiting wafer α) is placed on the loading rotating arm (23). Transfer the first wafer ■ and perform measurement. And 5
The wafer (2) is placed on standby in the rotating arm (23) for loading. As described above, the semiconductor wafers (2) stored in the cassette (A) are distributed to the two measurement units (2) and measurements are performed.

As explained above, according to this embodiment, even if the height positions of the rotary transfer arms provided in each measuring section and corresponding to the height positions of each mounting table are different, the preliminary alignment stage By raising and lowering the recessed position corresponding to each rotary arm, the object to be measured can be transported easily and reliably. Furthermore, since maintenance such as height alignment is not required, working time is shortened and operational efficiency is improved.

The present invention is not limited to the above-mentioned embodiments; for example, the same effects as in the above-mentioned embodiments can be obtained even if the rotary arm, which is a means of transporting each measuring section, is made to be able to rise and fall, and the height is adjusted using this rotary arm. It will be done. Furthermore, the conveyance means does not have to be a rotary arm, but may be belt conveyance, robot conveyance, or the like. Furthermore, when semiconductor wafers of different types are measured in each measuring section, different calibration wafers may be transported to the respective measuring sections for determination. Furthermore, the number of measurement units is not limited to two systems, and any number of systems may be used as long as the operation of each mechanism in the storage unit can be handled, and the object to be measured does not have to be a semiconductor wafer. <An LCD board etc. may also be used.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of a probe device in which two measuring parts are provided in one storage part to explain one embodiment of the method of the present invention, Fig. 2 is a front explanatory view of Fig. 1, and Fig. 3 is a side view of the storage section in Figure 1, Figure 4 is a diagram of the wafer transfer mechanism in Figure 1,
FIGS. 5 and 6 are diagrams for explaining transportation by the rotary arm in FIG. 1. 1... Semiconductor wafer 2... Storage section 3... Measurement section 9... Transfer mechanism 16... Preliminary alignment stage

Claims (1)

[Claims] In a measurement method in which an object to be measured stored in a storage container is pre-aligned, and the object to be measured from the pre-alignment mechanism is transported and measured by each conveying means of at least two measuring units, the height of the above-mentioned pre-alignment mechanism A measuring method characterized in that the object to be measured is conveyed to each measurement section by each of the above-mentioned conveyance means while controlling the position and measured.