WO2010071277A1

WO2010071277A1 - Probe station

Info

Publication number: WO2010071277A1
Application number: PCT/KR2009/002675
Authority: WO
Inventors: Jeon-Ho Jin; Ki-Uk Choi; Jin-Yung Jung; In-Wook Hwang; Woo-Yeol Kim; Chan-Wook Hwang
Original assignee: Secron Co., Ltd.
Priority date: 2008-12-19
Filing date: 2009-05-21
Publication date: 2010-06-24
Also published as: KR20100071239A; TW201024742A; KR101015602B1; TWI457569B

Abstract

A probe station includes a stage unit having a test space for testing a plurality of chips formed on a wafer, a loading unit providing the wafer for the stage unit, a first gas supplying unit disposed on a first sidewall of the stage unit, the first gas supplying unit supplying a first cleaning gas into the test space, and a first gas discharging unit disposed on a second sidewall of the loading unit, the first gas discharging unit discharging the first cleaning gas to remove particles from the test space and the second sidewall facing the first sidewall.

Description

PROBE STATION

The present invention relates to a probe station. More particularly, the present invention relates to a probe station for electrically testing a plurality of chips formed on a wafer.

Generally, a probe station includes a loading unit and a probing unit. The loading unit transfers a wafer on which a plurality of chips is formed and pre-aligns the wafer. The probing unit receives the wafer from the loading unit and tests electrical characteristics of the chips.

The loading unit picks up the wafer from a cassette in which a plurality of wafers is sequentially stacked and transfers the wafer to the probing unit.

The probing unit includes a chuck and an aligner. The chuck moves in x-y-z directions and rotates to direct the wafer toward a probe card through which the chips are electrically connected to a tester. Further, the aligner may adjust the position and orientation of both the wafer located on the chuck and the probe card.

Meanwhile, a relatively high degree of cleanliness in interiors of the loading unit and the probing unit may be required. Thus, it may be necessary to efficiently remove particles from the interiors of the loading unit and the probing unit. Particularly, when the probe station is utilized for testing a plurality of chips that are to be employed for a complementary metal-oxide semiconductor (CMOS) image sensor (CIS), an ultimately high degree of cleanliness is necessary.

Example embodiments of the present invention provide a probe station capable of removing particles from the interior thereof to maintain a high degree of cleanliness in the interior.

According to some example embodiments of the present invention, a probe station include a stage unit having a test space for testing a plurality of chips formed on a wafer, a loading unit providing the wafer for the stage unit, a first gas supplying unit disposed on a first sidewall of the stage unit, the first gas supplying unit supplying a first cleaning gas into the test space, and a first gas discharging unit disposed on a second sidewall of the loading unit, the first gas discharging unit discharging the first cleaning gas to remove particles from the test space and the second sidewall facing the first sidewall. Here, the second sidewall may include a first opening, and the first gas discharging unit comprises a plurality of guide bars secured to inner walls defining the first opening to guide the first cleaning gas to flow downward, the guide bars being arranged in parallel with each other.

In some example embodiments, the second sidewall may include a first opening, the first gas discharging unit may include a first cover covering the first opening, and the first cover may include an inclined portion extending from the second sidewall and being inclined against the second sidewall, and a bottom portion extending from an lower edge of the inclined portion to the second sidewall, the bottom portion having a second opening to discharge the second cleaning gas downward. Here, the first gas discharging unit may further include a first shutter to open/close the second opening. Further, the first gas discharging unit further may include a fan disposed at a position corresponding to the second opening to forcibly discharge the second cleaning gas. Furthermore, the first cover may have a “C” shape.

In an example embodiment, the first opening may be formed through a lower portion of the second sidewall.

In an example embodiment, the stage unit may include a chuck supporting the wafer, a stage disposed under the chuck, the stage linearly moving together with the chuck and a second cover surrounding the chuck, the second cover having a streamlined shape to allow smooth flow of the first cleaning gas introduced into the stage unit.

A probe station according to an example embodiment may further include an image sensing part optically detecting the position of chip formed on the wafer located on the stage unit, a driving part being disposed adjacent to a third sidewall connecting the first sidewall with the second sidewall, the driving part moving the image sensing part, a sealing part extending from the first sidewall to the second sidewall, the sealing part isolating the driving part from the test space.

In an example embodiment, the loading unit may include a load port supporting a cassette receiving the wafer, a transfer part transferring the load port to the stage unit and a control part facing the load port, and the control part controlling the transfer part, and the probe station may include a second gas supplying unit disposed over the transfer part, the second gas supplying unit providing a second cleaning gas for the transfer part and a second gas discharging unit disposed under the transfer part, the second gas discharging the second gas from the transfer part to remove particles from the transfer part. Here, the loading unit may further include a pre-aligner disposed under the load port, the pre-aligner pre-aligning the wafer transferred from the cassette. Further, the loading unit may further include a third cover covering the control part, the third cover having a streamlined structure to guide the second cleaning gas toward the transfer part. Furthermore, the loading unit may further include a buffer part located under the control part, the buffer part receiving a tested wafer and a fourth cover interposed between the buffer part and the transfer part, the fourth cover isolating the transfer part from the buffer part to prevent particles in the buffer part from entering into the transfer part.

In an example embodiment, the loading unit may further include a load port supporting a cassette receiving the wafer, a transfer part transferring the load port to the stage unit and a second shutter being positioned at a boundary between the load port and the transfer part to prevent particles in the cassette from entering into the transfer part. Here, the second shutter may be made of aluminum or aluminum alloy.

According to the example embodiments of the present invention, various parts installed in a stage unit may be prevented from interfering with the flow of a cleaning gas such that the cleaning gas may smoothly flow in the stage unit. Thus, particles may be efficiently removed from the stage unit. Further, various parts installed in a loading unit may be prevented from interfering with the flow of a cleaning gas such that the cleaning gas may smoothly flow in the loading unit. As a result, particles may be efficiently removed from the loading unit. Some example embodiments of the present invention may be employed in a plurality of systems for testing electrical characteristics of chips formed on the wafer.

Example embodiments of the present invention will become readily apparent along with the following detailed description when considered in conjunction with the accompanying drawings, wherein:

FIG. 1 is a perspective view illustrating a probe station in accordance with an example embodiment of the present invention;

FIG. 2 is a perspective view illustrating the stage unit in FIG. 1;

FIG. 3 is a perspective view illustrating the loading unit in FIG. 1; and

FIG. 4 is a perspective view illustrating the first gas discharging unit in FIG. 1

Embodiments of the present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like reference numerals refer to like elements throughout.

It will be understood that when an element is referred to as being “on”another element, it can be directly on the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first thin film could be termed a second thin film, and, similarly, a second thin film could be termed a first thin film without departing from the teachings of the disclosure.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising” or “includes” and/or “including” when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof.

Furthermore, relative terms, such as “lower” or “bottom” and “upper” or “top” may be used herein to describe one element's relationship to other elements as illustrated in the Figures. It will be understood that relative terms are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. For example, if the device in one of the figures is turned over, elements described as being on the “lower” side of other elements would then be oriented on “upper” sides of the other elements. The exemplary term “lower,” can therefore, encompass both an orientation of “lower” and “upper” depending on the particular orientation of the figure. Similarly, if the device in one of the figures is turned over, elements described as “below” or “beneath” other elements would then be oriented “above” the other elements. The exemplary terms “below” or “beneath” can, therefore, encompass both an orientation of above and below.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Example embodiments of the present invention are described herein with reference to cross-section illustrations that are schematic illustrations of idealized embodiments of the present invention. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments of the present invention should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, a region illustrated or described as flat may, typically, have rough and/or nonlinear features. Moreover, sharp angles that are illustrated may be rounded. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of a region and are not intended to limit the scope of the present invention.

FIG. 1 is a perspective view illustrating a probe station in accordance with an example embodiment of the present invention. FIG. 2 is a perspective view illustrating the stage unit in FIG. 1.

Referring to FIGS. 1 and 2, a probe station 100 in accordance with some example embodiments of the present invention includes a stage unit 110, a loading unit 120, a first gas supplying unit 130 and a second gas supplying unit 140. The probe station 100 may electrically connect a plurality of chips formed on a wafer to a tester (not shown) via a probe card (not shown). The tester applies electrical signals to the chips to determine whether each of the chips is good or bad. A flow direction of a first gas provided by the first gas supplying unit to the first gas discharging unit is defined as a first direction.

The stage unit 110 provides a test space 117 for testing electrical characteristics of the chips formed on the wafer.

In an example embodiment, the stage unit 110 may include a chuck 111, a stage 113 and a second cover 115. The chuck 111 supports the wafer. The stage 113 is positioned under the chuck 111. The stage 113 is connected to the chuck 111 such that the chuck 111 moves as the stage 113 moves. The second cover 115 covers the chuck 111 and the stage 113. For example, the second cover 115 may surround side faces of the chuck 111 and side faces of the stage 113.

The chuck 111 is positioned in the test space 117. The chuck 111 may secure the wafer using a vacuum force.

In an example embodiment, the stage unit 110 may further include a plurality of lift pins (not shown) to ascend/descend through the chuck 111 to support the wafer. Further, the stage unit 110 may include a vacuum pump (not shown) generating a vacuum force, a vacuum line (not shown) communicating with the vacuum pump, and a vacuum hole (not shown) formed through the chuck 111 to be connected with the vacuum line such that the chuck 111 may secure the wafer using the vacuum force.

The stage 113 is positioned under the chuck 111. The stage 113 is connected to the chuck 111 such that the chuck 111 may move as the stage 113 moves. For example, as the stage 113 moves in x-y-z directions, the chuck 111 moves in x-y-z directions. Further, as the stage 113 rotates, the chuck 111 revolves.

In an example embodiment, the stage unit 110 may further include a driving source (not shown) to be connected to the stage 113. For example, the driving source includes a cylinder, a linear motor, a ball screw, etc.

The second cover 115 covers a sidewall of the stage 113. The second cover 115 may prevent particles which may occur in an operation of the stage 113 from drifting into the test space 117. Further, the second cover 115 may have a streamline shape covering the sidewall of the stage 113. Thus, a flow resistance of the first cleaning air which is introduced in the test space 117 may decrease such that the first cleaning air flows smoothly.

FIG. 3 is a perspective view illustrating the loading unit in FIG. 1.

Referring to FIGS. 1 to 3, the loading unit 120 is positioned adjacent to the stage unit 110. The loading unit 120 is mounted to the stage unit 110 in a docking manner which is attachable and detachable between the stage unit 110 and the loading unit 120. The loading unit 120 may unload the wafer from a cassette 20 in which the wafer is stacked to the stage unit 110 and load the wafer to the stage unit 110.

In some example embodiment, the loading unit 120 may include a load port 121, a transfer part 122 and a control part 123. The load port 121 supports the cassette 20 in which a plurality of wafers is sequentially stacked. The transfer part 122 may include a transfer arm (not shown) for transferring the wafer from the cassette 20 to the stage unit 110. The control part 123 may include wirings and electric circuit devices for controlling the transfer part 122. For example, the load port 121, the transfer part 122 and the control part 123 may be arranged in a row.

The loading unit 120 may further include a second shutter 129. The second shutter 129 is positioned at the boundary between the load port 121 and the transfer part 122. The second shutter 129 may isolate the transfer part 122 from the load port 121. The second shutter 129 may move vertically or horizontally. For example, the transfer arm may load or unload the wafer between the cassette 20 positioned on the load port 121 and the transfer part 122 while the second shutter 129 is open. On the other hand, the transfer arm may stop operating while the second shutter 129 is closed. Thus, particles which remain in the cassette 20 may be prevented from drifting into the transfer part 122. The second shutter 129 may be made of aluminum, aluminum alloy, etc.

In an example embodiment, the loading unit 120 may further include a third cover 126 covering the control part 123 having the wirings and electrical circuits. The third cover 126 may guide a cleaning gas to flow downward toward the control part 123 to direct the cleaning gas into the transfer part 122. Thus, the cleaning gas which is introduced into the loading unit 120 may be intensively provided onto the wafer positioned on the transfer arm to effectively remove the particles which remain on the wafer.

In an example embodiment, the loading unit 120 may further include a buffer part 127 disposed under the control part 123 and a fourth cover 128 isolating the transfer part 122 from the buffer part 127.

The buffer part 127 may have a space for storing a wafer. The wafer may include the wafer utilized for polishing tips of the probe card and a tested wafer. The buffer part 127 include a first table (not shown) of supporting the wafer utilized for polishing tips of the probe card and a second table (not shown) for supporting the tested wafer.

The fourth cover 128 is interposed between the buffer part 127 and the transfer part 122. The fourth cover 128 may isolate the buffer part 127 from the transfer part 122 such that particles which remain in the buffer part 127 may be prevented from drifting into the transfer part 122. Further, the fourth cover 128 may prevent the cleaning gas flowing downward in the transfer part from entering into the buffer part 127 to efficiently drain out the cleaning gas.

In an example embodiment, the loading unit 120 may further include a preliminary aligner 125 for pre-aligning the wafer.

The preliminary aligner 125 may be, for example, positioned under the load port 121. The preliminary aligner 125 may include a subsidiary chuck (not shown) supporting the wafer and pre-aligning the wafer and an information reader (not shown) for reading identification information of the wafer such as an optical character reader and a bar code reader.

FIG. 4 is a perspective view illustrating a first gas supplying unit in FIG. 1.

Referring to FIGS. 1 and 4, the first gas supplying unit 130 is disposed on a first sidewall of the stage unit 110. On the other hand, the first gas discharging unit 140 is disposed on a second sidewall of the stage unit 110. The second sidewall is opposite to the first sidewall. Thus, the first gas supplying unit 130 provides the first cleaning gas into the stage unit 110 to drain out the first cleaning gas through the second sidewall of the stage unit 110. Meanwhile, a probe card changer (not shown) for changing the probe card may be positioned on one of sidewalls of the stage unit 110, combining the first sidewall and the second sidewall.

The first gas supplying unit 130, for example, may include a fan filter unit (not shown). Further, the first gas supplying unit 130 may include a high-efficiency particulate air (HEPA) filter or an ultra low penetration air (ULPA) filter. The HEPA filter and the ULPA filter are widely employed in various fields. Thus, any detailed explanation of the HEPA filter and the ULPA filter is omitted.

In an example embodiment, the stage unit 110 further includes a first opening 117 formed on the second sidewall thereof. The first cleaning gas from the first gas supplying unit 130 may flow into the stage unit 110 and may drain out through the first opening 117.

The first gas discharging unit 140 may include a first cover 143 covering the first opening 117. The first cover 143 may have a second opening 143c to guide the first cleaning gas to flow downward and drain out.

The first cover 143 has a width measured along the first direction. In one example embodiment, the cover 143 has a “C” shape. In another example embodiment, the first cover 143 has a width becoming smaller away from a bottom portion of the first cover 143. The first cover 143 may prevent external light from being irradiated into the stage unit 110. When the probe station 100 is utilized to test chips formed on the wafer, which are employed to manufacture a complementary metal-oxide semiconductor (CMOS) image sensor (CIS), the first cover 143 may prevent the external light from entering into the stage unit 110.

In some example embodiment, the first cover 143 may include an inclined portion 143a and a bottom portion 143b. The inclined portion 143a may extend from the second sidewall of the stage unit 110 for covering the first opening 117 to be inclined to the second sidewall of the stage unit 110. The bottom portion 143a extends from a lower edge of the inclined portion 143a to the second sidewall of the stage unit 110. The second opening 143a is formed through the bottom portion 143a. The first cleaning gas may be discharged through the second opening 143a.

In some example embodiments, the first gas discharging unit 140 may further include a plurality of guide bars 141 secured to inner walls defining the first opening 117, a first shutter 145 for opening and closing the second opening 143c and a fan 147 disposed to cover the second opening 143c for forcibly draining out the first cleaning gas through the second opening 143c.

The guide bars 141 may be positioned in parallel to each other. The guide bars 141 may guide the first cleaning gas to flow toward the first opening 117 to introduce the first cleaning gas toward the bottom portion 143a of the first cover 143. The guide bars 141 each may have a round shape. The first gas discharging unit 140 may further include a combining member 142. The combining member 142 may extend vertically from one of the inner walls defining the first opening 117 to another of the inner walls to combine the guide bars 141 with one another.

The first shutter 145 may open/close the second opening 143c to control an amount of the cleaning gas which drains out through the second opening 143c. For example, the flow rate of the cleaning gas may vary according to an amount of opening of the second opening 143c. Thus, the particles which may remain in the stage unit 110 may be effectively removed by using the cleaning gas.

In some example embodiments of the present invention, the probe station 100 may further include an image sensing part 150, a driving part 155 and a sealing part 157.

Referring to FIG. 2, the image sensing part 150 is positioned over the chuck 111 which supports the wafer. The image sensing part 150 optically detects the position of each of the chips formed on the wafer located on chuck 111. The image sensing part 150 may linearly move in the first direction toward the wafer located on chuck t 111.

For example, the image sensing part 150 includes an optical camera (not shown) of picturing a pattern of the chips and a bridge (not shown) of connecting the optical camera to the driving part 155.

The driving part 155 may be disposed on an inner sidewall of the stage unit 110. The driving part 155 may guide the motion of the image sensing part 150 and may move the imaging sensing part 150. For example, the driving part 155 may include a linear motion guide extending in the first direction on the inner sidewall of the stage unit 110.

The sealing part 157 may be disposed in parallel with the driving part 155. For example, the sealing part 157 may extend in the first direction. The sealing part 157 may isolate the driving part 155 from the test space 117. Thus, particles which may occur in an operation of the driving part 155 may be prevented from entering into the test space 155.

In some example embodiments, the probe station 100 may further include a second gas supplying unit 160 and a second gas discharging unit 170.

Referring again to FIG. 3, the second gas supplying unit 160 is disposed on the loading unit 120. For example, the second gas supplying unit 160 supplies a second cleaning gas for the transfer part 122. Further, the second gas supplying unit 160, for example, may include a fan filter unit (not shown). The second gas supplying unit 160 may include the HEPA filter or the ULPA filter.

The second gas discharging unit 170 is located below the loading unit 120. The second gas discharging unit 170 discharges downward the second cleaning gas with the particles from the transfer part 122. The second gas discharging unit 170 may include a drain hole for efficiently draining out the second cleaning gas.

The second gas supplying unit 160 and the second gas discharging unit 170 may supply and discharge the second cleaning gas in a downstream manner to effectively remove the particles from the loading unit 120.

According to the example embodiments of the present invention as described above, various parts installed in a stage unit may be prevented from interfering with the flow of a cleaning gas such that the cleaning gas may smoothly flow in the stage unit. Thus, particles may be efficiently removed from the stage unit. Further, various parts installed in a loading unit may be prevented from interfering with the flow of a cleaning gas such that the cleaning gas may smoothly flow in the loading unit. As a result, particles may be efficiently removed from the loading unit. Some example embodiments of the present invention may be employed in a plurality of systems for testing electrical characteristics of chips formed on the wafer.

Although the example embodiments of the present invention have been described, it is understood that the present invention should not be limited to these example embodiments but various changes and modifications can be made by those skilled in the art within the spirit and scope of the present invention as hereinafter claimed.

Claims

A probe station comprising:

a stage unit having a test space for testing a plurality of chips formed on a wafer;

a loading unit providing the wafer for the stage unit;

a first gas supplying unit disposed on a first sidewall of the stage unit, the first gas supplying unit supplying a first cleaning gas into the test space; and

a first gas discharging unit disposed on a second sidewall of the loading unit, the first gas discharging unit discharging the first cleaning gas to remove particles from the test space and the second sidewall facing the first sidewall.
The probe station of claim 1, wherein the second sidewall includes a first opening, and the first gas discharging unit comprises a plurality of guide bars secured to inner walls defining the first opening to guide the first cleaning gas to flow downward, the guide bars being arranged in parallel with each other.
The probe station of claim 1, wherein the second sidewall includes a first opening, the first gas discharging unit includes a first cover covering the first opening, and the first cover includes an inclined portion extending from the second sidewall and being inclined against the second sidewall, and a bottom portion extending from an lower edge of the inclined portion to the second sidewall, the bottom portion having a second opening to discharge the second cleaning gas downward.
The probe station of claim 3, wherein the first gas discharging unit further comprises a first shutter to open/close the second opening.
The probe station of claim 3, wherein the first gas discharging unit further comprises a fan disposed at a position corresponding to the second opening to forcibly discharge the second cleaning gas.
The probe station of claim 3, wherein the first cover has a “C” shape.
The probe station of claim 2, wherein the first opening is formed through a lower portion of the second sidewall.
The probe station of claim 1, wherein the stage unit comprises:

a chuck supporting the wafer;

a stage disposed under the chuck, the stage linearly moving together with the chuck; and

a second cover surrounding the chuck, the second cover having a streamlined shape to allow smooth flow of the first cleaning gas introduced into the stage unit.
The probe station of claim 1, further comprising:

an image sensing part optically detecting the position of a chip formed on the wafer located on the stage unit;

a driving part being disposed adjacent to a third sidewall connecting the first sidewall with the second sidewall, the driving part moving the image sensing part; and

a sealing part extending from the first sidewall to the second sidewall, the sealing part isolating the driving part from the test space.
The probe station of claim 1, wherein the loading unit comprises:

a load port supporting a cassette receiving the wafer;

a transfer part transferring the load port to the stage unit; and

a control part facing the load port, the control part controlling the transfer part,

further comprising:

a second gas supplying unit disposed over the transfer part, the second gas supplying unit providing a second cleaning gas for the transfer part; and

a second gas discharging unit disposed under the transfer part, the second gas discharging the second gas from the transfer part to remove particles from the transfer part.
The probe station of claim 10, wherein the loading unit further comprises a pre-aligner disposed under the load port, the pre-aligner pre-aligning the wafer transferred from the cassette.
The probe station of claim 10, wherein the loading unit further comprises a third cover covering the control part, the third cover having a streamlined structure to guide the second cleaning gas toward the transfer part.
The probe station of claim 10, wherein the loading unit further comprises:

a buffer part located under the control part, the buffer part receiving a tested wafer; and

a fourth cover interposed between the buffer part and the transfer part, the fourth cover isolating the transfer part from the buffer part to prevent particles in the buffer part from entering into the transfer part.
The probe station of claim 1, wherein the loading unit comprises:

a load port supporting a cassette receiving the wafer;

a transfer part transferring the load port to the stage unit; and

a second shutter being positioned at a boundary between the load port and the transfer part to prevent particles in the cassette from entering into the transfer part.
The probe station of claim 14, wherein the second shutter is made of aluminum or aluminum alloy.