JPS63237429A - Wafer prober - Google Patents

Abstract

PURPOSE:To shorten a waiting time until a start of a measuring operation and to enhance a productivity by a method wherein two independent wafer chucks are installed and one wafer can be measured while the other wafer is aligned finely so that the measuring operation of the latter can be started immediately after completion of the measuring operation of the former. CONSTITUTION:When a fine-alignment operation is completed, a wafer chuck 5a is shifted under a probe card 11; after a pad on a chip to be measured has been brought into contact with a probe, a measuring operation is executed by using a tester. When the measuring operation of one chip is completed, following chips are shifted intermittently, and these chips are measured in succession. On the other hand, simultaneously with a start of the measuring operation of a wafer 6a, a wafer 6b which has been accommodated in a carrier 7b is placed on a chuck 5b. Simultaneously with the start of an unloading operation of the wafer chuck 5a after completion of the measuring operation of the wafer 6a, the wafer chuck 5b is shifted under the probe card 11 and th measuring operation of the wafer 6b is started. After that, above-mentioned operations are separated, and all the wafers in carriers 7a and 7b are measured; accordingly, the wafers can be measured successively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wafer blobber used for inspecting integrated circuit elements formed on a semiconductor substrate.

° [Prior Art] The main role of a wafer prober for inspecting integrated circuit elements (hereinafter referred to as chips) formed on a semiconductor substrate (hereinafter referred to as wafer) is to inspect the electrical current of chips on the wafer.
This is to accurately contact the tip of a probe formed on a probe card with <hereinafter referred to as a pad> to make it possible to measure one or more chips, and this is usually the state. The process is called blobbing.

In normal wafer inspection, such 10-bings are repeated to inspect all chips on the wafer.

The operation of a typical fully automatic wafer prober is as follows. That is, the wafer stored in the carrier is taken out from the carrier by means such as a belt or a vacuum hand, the orientation flat of the taken out wafer is detected, and the orientation flat is aligned in a certain direction and the sample stage (hereinafter referred to as wafer chuck) is moved. ) (usually called loading this).

The wafer mounted on the wafer chuck is measured at three points on its outer circumference using a capacitive sensor or the like to find the center, and then the thickness, warpage, etc. of the wafer are measured. After this, position correction (hereinafter referred to as fine alignment) is performed to create a state in which the tip probe and the pad can accurately contact each other. When fine alignment is completed, the wafer chuck moves directly below the tip probe, brings the tip probe into contact with the pad, and starts measuring the chip. When all chips on the wafer have been measured, the wafer is stored in a carrier (this is called unloading). When unloading is completed, the next wafer is loaded and measured in the same manner.

[Problem that the invention seeks to solve]

With the conventional wafer prober as described above, the time required from loading the wafer onto the wafer chuck to the point at which fine alignment is completed, that is, just before the measurement of chips on the wafer begins, is approximately 40 to 80 seconds. It is. This period of 40 seconds to 80 seconds is
(hereinafter referred to as a tester) is in a state where it is not performing a measurement operation. Assuming that this loss time that occurs each time one wafer is measured is 60 seconds, there is a time loss of 49 minutes when measuring 50 wafers, and during this time the tester is on standby without performing any measurement operations. become.

In this way, with conventional wafer probers, there is a waiting time during which no measurement is performed between the time when the wafer is loaded and the time when chip measurement begins, and this waiting time becomes lost time, which improves the productivity of the wafer prober. It is a factor that hinders This is because conventional probers have only one wafer chuck, and with such a configuration, it is impossible to eliminate time loss during wafer loading and unloading.

It is an object of the present invention to eliminate the above-mentioned drawbacks of conventional wafer probers and to provide two independent wafer chucks, so that while the wafer on one wafer chuck is being measured, the wafer on the other is being measured. The wafer on the wafer chuck is fine-aligned, and the measurement of the latter can be started immediately after the measurement of the former is completed, thereby reducing the waiting time until the start of measurement and improving productivity. The purpose of the present invention is to provide a wafer prober.

[Means for solving problems]

The wafer prober of the present invention includes two X-axis guides that guide lateral movement in a horizontal plane, two X-stages installed astride the X-axis guides, and two two Y-axis guides provided on each of the stages, two Y-stages whose vertical movement in a horizontal plane is guided by the Y-axis guides, and f provided on each of the two Y-stages. : Two Zθ stages and the two Z
A stage base having two wafer chucks provided on each of the θ stages, and in which the two wafer chucks are movable between two positions, a measurement position and a standby position, by linear motion or rotational motion. a probe card provided above the measurement position of the wafer chuck; at least one alignment device provided above the standby position of the wafer chuck; and a wafer to be mounted on the wafer chuck. at least one carrier for loading or unloading the wafer contained in the carrier onto or unloading the wafer chuck, a tester measurement section connected to the probe card, the stage base, and the alament device. The apparatus includes a control section that controls operations of the loader and the tester measurement section.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing a first embodiment of the present invention, and FIG. 2 is a block diagram showing a control system of the embodiment of FIG.

In FIG. 1, two parallel horizontal axis guides (X-axis guides) 8 are provided on the stage base 1, and two X-stages are seated astride the X-axis guides 8. 2a and 2b are installed.

The X stages 2a and 2b can freely reciprocate on the X-axis guide 8. Note that the X stage 2a and the X stage 2b have a structure that does not mechanically interfere with each other. On the X stages 2a and 2b, there are guides in the vertical axis direction (
Y-axis guides) 9a and 9b are provided, and X stages 3a and 3b are mounted on these Y-axis guides 9a and 9b, respectively. Like the X stages 2a and 2b, the X stages 3a and 3b can reciprocate independently on the Y axis guide 9a or 9b. X stage 2a and 2b and X stage 3
Both a and 3b can be reciprocated by driving means such as a feed screw mechanism. X stage 3a and 3b
Zθ stages 4a and 4b (detailed illustrations are omitted) are provided above, respectively, and these are coupled to wafer chucks 5a and 5b, respectively. The Zθ stages 4a and 4b are capable of vertically reciprocating the wafer chucks 5a and 5b mounted thereon, respectively, and also rotating with the vertical direction as an axis of rotation. In this way, the wafer chucks 5a and 5b can independently perform reciprocating movements in the horizontal, vertical, and vertical directions and rotational movement in the horizontal plane on the stage base 1.

Above the wafer chucks 5a and 5b, there is a mechanism for holding a probe card 11 called a head plate 1, which is fixed above the center of the stage base 1. The probe card 11 has probes that come into contact with pads in the chips of the wafers 6a and 6b, and is electrically connected to the tester measurement section 55. The alignment devices 10a and 10b are installed above the wafer chucks 5a and 5b, respectively, and the wafer 6
This is to perform fine alignment of a or 6b. The alignment devices K 10a and 10b are He-
It is constructed using a Ne laser, a semiconductor laser, a video camera, etc. Although not shown in FIG. 1, capacitive sensors for detecting the center position, thickness, warpage, etc. of the wafers 6a and 6b are installed above each of the wafer chucks 5a and 5b.

As shown in FIG. 2, the X stage 2a and the X stage 3a
The Zθ stage 4a and the wafer chuck 5a are controlled by a stage controller 52a, and similarly the X stage 2b, Y stage 3b, Zθ stage 4b, and wafer chuck 5b are controlled by a stage controller 52b. The wafer 6a or 6b is taken out from the carrier 7a or 7b and supplied to the wafer chucks 5a and 5b.
The wafer loader for storing the wafer in the loader control unit 51
controlled by Further, the alignment device I/devices 10a and 10b are controlled by the alignment device 1 to the control section 53. These control units are controlled by a main control unit 50. The main control section 50 also has functions such as communication with a tester (not shown).

Next, the operation of the above embodiment will be explained.

A wafer is stored in the carrier 7a, and is loaded onto the wafer chuck 5ac' knee by a wafer loader. The wafer chuck 5a moves below the capacitive sensor (not shown), measures the center and thickness or warp of the wafer 6a, and then moves below the alignment device 10a. The alignment device 10a collects data for alignment of the surface of the wafer 6a, analyzes it in the alignment control section 53, and simultaneously controls the X stage 2 by the stage control 52a.
Fine alignment of the wafer 6a is performed by driving the Y stage 3a and Zθ stage 4a.

When fine alignment is completed, the wafer chuck 5
a moves below the probe card 11, brings the pad of the chip to be measured and the tip probe into contact, and the tester measuring section 55 and the tester perform measurement. When the measurement of one chip is completed, it moves intermittently to the next chip to be measured, measures the next chip, and then sequentially measures the remaining chips.

On the other hand, at the same time that the measurement of the wafer 6a is started, the wafer 6b stored in the carrier 7b is loaded onto the chuck 5b by the wafer loader. - Similarly to the case of the wafer 6a, the wafer chuck 6b moves below the capacitive sensor to measure the center and thickness or warp of the wafer 6b, and then moves below the alignment device iob.

The alignment unit 1Ob collects data for alignment of the surface of the wafer 6b and performs the alignment control unit 5.
3, and at the same time, the stage controller 52b controls the X stage 2b, Y stage 3b, and Zθ stage 4b.
Fine alignment of the wafer 6b is performed by driving the wafer 6b, and when the fine alignment of the wafer 6b is completed, it waits at that position. Generally, the alignment time is much shorter than the measurement time for one wafer, so the wafer 6b is always on standby.

At the same time that the measurement of the wafer 6a is completed and the wafer chuck 5a starts an unloading operation, the wafer chuck 5b starts moving below the probe card 11. Then, the chip to be measured and the tip probe are brought into contact with each other, and measurement of the wafer 6b is started. Thereafter, intermittent movement of the wafer chips is repeated until measurement of all chips on the wafer 6b is completed, and an unloading operation is started. When the wafer chuck 5b enters the unloading operation, the wafer chuck 5a moves below the probe card 11 and starts measuring the next wafer mounted on the wafer chuck 5a.

Thereafter, the above operations are repeated to measure all the wafers on carriers 7a and 7b.

FIG. 3 is a perspective view showing a second embodiment of the invention.

In FIG. 3, X stages 22a and 22b, Y stages 23a and 23b, Zθ stages 24a and 24b, and wafer chucks 25a and 25b are the same as in the first embodiment.

In this embodiment, the probe card 31 is attached to the wafer chuck 2.
The alignment device 30 is installed above the wafer chuck 25a, and there is only one alignment device 30. Furthermore, the stage base 21 is configured to rotate within a horizontal plane by a stage base rotation control section 66. When the stage base 21 rotates 180 degrees, the wafer chuck 5a that was under the alignment device 30 is positioned under the probe card 11, and the wafer chuck 5b that was under the probe card 31 is positioned under the alignment device 30. It becomes like this.

Next, the operation of the second embodiment will be explained.

A wafer to be measured is stored in the carrier 27,
The wafer chuck 25 is mounted by a wafer loader (not shown).
It is mounted on a. The wafer chip cue 25a moves below the capacitive sensor (not shown) and measures the center and thickness or warp of the wafer 6a, and then moves below the alignment device 3o.

When the alignment is completed by the alignment device 30, the stage base 21 is moved to the stage base rotation control unit 6.
The wafer 1 chuck 25a moves below the 10-wafer card 31 and starts measurement. On the other hand, at the same time as the rotation of the stage base 21 is completed, the next wafer is loaded from the carrier 27 onto the wafer chuck 25b and aligned, and when the alignment is completed, the next wafer is placed on standby. When the measurement of the wafer 6a is completed, the stage base 21 is further rotated by 18 degrees, and the measurement of the wafer 6b is started. Thereafter, the above operations are repeated to measure all the wafers accommodated in the carrier 27.

[Effects of the Invention] 'As explained above, the present invention has two wafer chucks on which wafers can be mounted independently, and while the wafer on one wafer chuck is being measured, the wafer on the other wafer chuck is not being measured. By aligning and waiting for the wafer on the other wafer chuck, and then immediately starting measuring the wafer on the other wafer chuck, it is possible to measure the wafer continuously. This has the effect of eliminating the waiting time for loading and alignment, thus improving productivity.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing a first embodiment of the present invention, Fig. 2 is a block diagram showing a control system of the embodiment of Fig. 1, and Fig. 3 is a perspective view showing a second embodiment of the invention. It is a diagram. 1/21...Staise Base, 2a/2b/22a-
22b-X stage, 3a-3b/23a/23b-
Y stage, 4a, 4b, 24a, 24b-zθ stage, 5a-5b-25a-25b...Wafer chuck, 6a, 6b...Wafer, 7a, 7b, 27...Carrier, 8, 28a, 28b ...X-axis guide, 9a.
9b/29a/29b...Y-axis guide, 10a/10
b.30... Alignment device, 11.31... Probe card, 50... Main control section, 51... Loader control section, 52a.52b... Stage control section, 53.
63... Alignment control section, 55.65... Tester measurement section. Agent Patent Attorney Susumu Uchihara L+-I, Figure 2

Claims (1)

[Claims] Two X-axis guides that guide lateral movement in a horizontal plane, two X-stages installed astride the X-axis guides, and the two X-stages. two Y-axis guides provided on each of the two Y-axis guides, two Y-stages whose vertical movement in a horizontal plane is guided by the Y-axis guides, and two Y-stages provided on each of the two Y-stages. Zθ
It has a stage and two wafer chucks provided on each of the two Zθ stages, and the two wafer chucks are moved between two positions, a measurement position and a standby position, by linear movement or rotational movement. a stage base that is movable; one probe card provided above the measurement position of the wafer chuck; at least one alignment device provided above the standby position of the wafer chuck; and the wafer chuck. at least one carrier for accommodating a wafer to be mounted on the wafer; a loader for loading or unloading the wafer accommodated in the carrier onto or from the wafer chuck; a tester measurement section connected to the probe card; A wafer prober comprising a stage base, a control section that controls operations of the alament device, the loader, and the tester measurement section.