Wafer inspection apparatuses

A wafer inspection apparatus includes a support structure including a frame and vacuum chucks mounted thereon, each vacuum chuck having a support surface including a vacuum suction portion, the support structure configured to structurally support a wafer on one or more vacuum chucks, the frame defining an opening larger than an area of the wafer. The wafer inspection apparatus includes an electromagnetic wave emitter configured to irradiate an inspection electromagnetic wave to the wafer, a sensor configured to receive the inspection electromagnetic wave from the wafer based on the inspection electromagnetic wave passing through the wafer, and a driver configured to move at least one of the electromagnetic wave emitter or the frame to change an irradiation location of the wafer. Each vacuum chuck is configured to be selectively movable between a first location and a second location in relation to the frame.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims benefit of priority, under 35 U.S.C. § 119, to Korean Patent Application No. 10-2019-0102565 filed on Aug. 21, 2019 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND

The present disclosure relates to wafer inspection apparatuses.

In order to manage the quality of semiconductor wafers, an inspection process of the semiconductor wafers is performed during semiconductor wafer manufacturing.

In general, a vacuum chuck is used in a wafer inspection apparatus to hold a semiconductor wafer during inspection of the wafer. Most vacuum chucks apply a vacuum to a rear surface of a wafer to hold the wafer in place. Since a reflective inspection apparatus detects electromagnetic waves reflected from a front surface of a wafer, wafer measurement may not be disturbed even when a vacuum chuck is disposed on a rear surface of the wafer. However, in a transmissive inspection apparatus, electromagnetic waves cannot pass through a wafer region in contact with a vacuum chuck, and thus, there may be an unmeasurable region.

SUMMARY

Some example embodiments provide a wafer inspection apparatus configured to increase in an inspection area of a wafer.

According to some example embodiments, a wafer inspection apparatus may include a support frame, an electromagnetic wave emitter, a sensor, and a driver. The support structure may include a frame, the frame including a plurality of vacuum chucks, each vacuum chuck of the plurality of vacuum chucks being mounted on the frame and each having a support surface including a vacuum suction portion. The support structure may be configured to structurally support a wafer on one or more vacuum chucks of the plurality of vacuum chucks, the frame defining an opening larger than an area of the wafer. The electromagnetic wave emitter may be configured to irradiate an inspection electromagnetic wave to the wafer. The sensor may be configured to receive the inspection electromagnetic wave from the wafer based on the inspection electromagnetic wave passing through the wafer. The driver may be configured to move at least one of the electromagnetic wave emitter or the frame to change an irradiation location of the wafer. Each vacuum chuck of the plurality of vacuum chucks may be configured to be selectively movable between a first location and a second location in relation to the frame.

According to some example embodiments, a wafer inspection apparatus may include a frame defining an opening, the frame configured to structurally support a wafer in the opening, wherein the opening is larger than an area of the wafer. The wafer inspection apparatus may include a plurality of first vacuum chucks and a plurality of second vacuum chucks. Each vacuum chuck of the plurality of first vacuum chucks and the plurality of second vacuum chucks may have a support surface including a vacuum suction portion. The plurality of first vacuum chucks and the plurality of second vacuum chucks may be configured to be movable between a first location of the frame and a second location of the frame. The support surface of each vacuum chuck may be configured to be coplanar with a reference plane for supporting the wafer when the vacuum chuck is at the first location of the frame. The wafer inspection apparatus may include an electromagnetic wave emitter configured to irradiate an inspection electromagnetic wave to a rear surface of the wafer, a sensor on the wafer, the sensor configured to receive the inspection electromagnetic wave from the wafer based on the inspection electromagnetic wave passing through the wafer, a driver configured to move the electromagnetic wave emitter to change an irradiation location on the rear surface of the wafer, and processing circuitry configured to control movements of the driver and the plurality of first and second vacuum chucks. The plurality of first vacuum chucks and the plurality of second vacuum chucks may be configured to be moved to the second location to deviate from a path of the inspection electromagnetic wave between the wafer and the electromagnetic wave emitter. The plurality of first vacuum chucks may be configured to be moved to the first location such that the support surfaces of the plurality of first vacuum chucks are in contact with first contact regions of the rear surface of the wafer, and the plurality of second vacuum chucks may be configured to be moved to the first location such that the support surfaces of the plurality of second vacuum chucks are in contact with second contact regions of the rear surface of the wafer, the first and second contact regions being different regions of the rear surface of the wafer.

According to some example embodiments, a wafer inspection apparatus may include a support structure including a frame. The frame may include a plurality of vacuum chucks. Each vacuum chuck of the plurality of vacuum chucks may be mounted on the frame and each vacuum chuck may have a support surface including a vacuum suction portion. The support structure may be configured to structurally support a wafer on one or more vacuum chucks of the plurality of vacuum chucks. The frame may define an opening larger than an area of the wafer. Each vacuum chuck may be configured to be positioned such that the support surface of the vacuum chuck is coplanar with a reference plane on which the wafer is supported by the support structure. The wafer inspection apparatus may include an electromagnetic wave emitter configured to irradiate an inspection electromagnetic wave to the wafer, a sensor configured to receive the inspection electromagnetic wave from the wafer based on the inspection electromagnetic wave passing through the wafer, and a driver configured to move at least one of the electromagnetic wave emitter or the frame to change an irradiation location of the wafer. Each vacuum chuck of the plurality of vacuum chucks may be configured to be separated from the reference plane to descend along the frame or to be flipped downwardly in relation to the frame.

DETAILED DESCRIPTION

FIG.1is a schematic diagram of a transmissive wafer inspection system according to some example embodiments, andFIG.2is a perspective view of a transmissive wafer inspection apparatus employable in the system illustrated inFIG.1.

The wafer inspection system300, illustrated inFIG.1, may include a chamber101provided with a wafer inspection apparatus200, a control unit210configured to control the wafer inspection apparatus200, and an analysis unit240configured to analyze a result measured by the wafer inspection apparatus200. The wafer inspection system300may further include a display unit250connected to the analysis unit240to display the measured result and/or the analyzed result. The display unit250may be understood to be any display device configured to display an image, including, without limitation, a light emitting diode (LED) display screen.

As illustrated inFIG.1, the control unit210and/or the analysis unit240may be included in, may include, and/or may be implemented by, one or more instances of processing circuitry such as hardware including logic circuits; a hardware/software combination such as a processor executing software; or a combination thereof. For example, the processing circuitry more specifically may include, but is not limited to, a processor that may include central processing unit (CPU), an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA), a System-on-Chip (SoC), a programmable logic unit, a microprocessor, application-specific integrated circuit (ASIC), etc. In some example embodiments, the processing circuitry of control unit210and/or analysis unit240may include a non-transitory computer readable storage device (e.g., memory), for example a solid state drive (SSD), storing a program of instructions, and a processor coupled to the storage device (e.g., via a bus) and configured to execute the program of instructions to implement the functionality of the control unit210and/or the analysis unit240. Accordingly, a control unit210and/or analysis unit240as described herein may be interchangeably referred to as “processing circuitry” that may be configured to implement any and all functionality of the control unit210and/or analysis unit240as described herein.

The wafer inspection apparatus200is a transmissive inspection apparatus analyzing characteristics of a wafer W using a manner in which inspection electromagnetic waves pass through the wafer W. In some example embodiments, the wafer inspection apparatus200includes a support structure100supporting a wafer W (e.g., structurally supporting a weight, or load, of the wafer W), an emission unit140(also referred to interchangeably herein as an electromagnetic wave emitter) configured to irradiate one or more inspection electromagnetic waves L1to the wafer W, and a detection unit160(also referred to interchangeably herein as a sensor) on (e.g., over, isolated from direct contact with or in direct contact with) the wafer W and configured to receive (e.g., detect) one or more inspection electromagnetic waves L2passing through the wafer W. The one or more inspection electromagnetic waves L2may include at least a portion of the one or more inspection electromagnetic waves L2irradiated to the wafer W, such that the detection unit160may detect an electromagnetic wave L2from the wafer W based on the inspection electromagnetic wave L2being irradiated to the wafer W as inspection electromagnetic wave L1and passing through the wafer W as inspection electromagnetic wave L2.

An inspection electromagnetic wave, used in the wafer inspection apparatus200, refers to an electromagnetic wave having a magnitude, or the like, varying depending on physical properties of a wafer W, an inspection target, after passing through the wafer W.

FIG.2is a perspective view of a wafer inspection apparatus200employable in some example embodiments.

As illustrated inFIG.2, a support structure100, employed in the wafer inspection apparatus200, may structurally support a wafer W (e.g., may support the load of the wafer W). The support structure100may include a frame110, defining an opening OP larger than an area of the wafer W, and a plurality of vacuum chucks150A1,150A2, and150A3and150B1,150B2, and150B3that are each mounted on a frame110to be disposed in the opening OP defined by the frame110. Each vacuum chuck of the plurality of vacuum chucks150A1,150A2, and150A3and150B1,150B2, and150B3may have a support surface155provided with (e.g., including) a vacuum suction portion VH, which may be an opening via which a vacuum may be applied. The support structure100may structurally support the wafer W on one or more vacuum chucks of the plurality of vacuum chucks150A1,150A2, and150A3and150B1,150B2, and150B3. For example, the support structure100may structurally support the wafer W on some but not all of the vacuum chucks of the plurality of vacuum chucks150A1,150A2, and150A3and150B1,150B2, and150B3.

In some example embodiments, the support structure100may include a base plate121and four support members125mounted on corners of the base plate121to support the frame110. The frame110may be fixed to an upper end of the support members125by a fastening means125P such as a screw or a pin.

The frame110may include three sides and may have a rectangular structure in which an open side is open, for example, a [-shaped structure. Restated, the frame110may include a rectangular frame, a circular frame, or a [-shaped frame. The wafer W may be loaded and unloaded through the open side of the frame110(indicated by “WR”). A shape of the frame110is not limited thereto, and the frame110may have various shapes such as a rectangle and a circle (seeFIGS.8and9).

The vacuum chucks150A1,150A2,150A3,150B1,150B2, and150B3, employed in some example embodiments, may be respectively configured to be movable along the frame110, and may be divided into at least two groups (e.g., a plurality of groups of vacuum chucks), each group of vacuum chucks including three chucks, (a first group and a second group). Each group of the vacuum chucks150A1,150A2,150A3and150B1,150B2, and150B3may be mounted on three sides of the frame120to support (e.g., structurally support) the wafer W to be disposed on an opening OP. The opening OP may be defined by the frame110and may be configured such that the entire region of the wafer W is exposed to be inspected. In some example embodiments, the movement of the vacuum chucks150A1,150A2,150A3and150B1,150B2, and150B3may be performed for each group to increase a wafer inspection area, which will be described later with reference toFIGS.4to7.

Each vacuum chuck of the plurality of vacuum chucks150A1,150A2, and150A3and150B1,150B2, and150B3may include a support surface155which may be in contact with a rear surface of the wafer W. While a vacuum chuck is in contact with the support surface155, the inside of the vacuum chuck is brought into a vacuum state or a low-pressure state by a vacuum suction portion VH, such that a vacuum may be applied to a portion of the wafer W via the vacuum suction portion VH to at least partially hold the wafer W in place. Thus, the wafer W may be stably held on the support surface155during the wafer inspection process.

As illustrated inFIG.3, such a vacuum may extend in the frame110and may be performed through a first channel CH1, extending into the frame110and being in fluid communication with an external vacuum source900, and a second channel CH2extending into a vacuum chuck and being in fluid communication with the first channel CH1. The vacuum suction portion VH may be connected to (e.g., in fluid communication with) the second channel CH2and may be provided to include a concave structure formed on the support surface155.

In addition, the wafer inspection apparatus200may include a moving unit130(also referred to herein as a driver) that may move the emission unit140to change an irradiation location W1of the wafer W (e.g., a location W1on the rear surface Wb of the wafer W to which the inspection electromagnetic wave L1is irradiated). The moving unit130may include, for example, a servo actuator, including a linear servo actuator. In some example embodiments, the moving unit130may move the frame in relation to the wafer W in order to change an irradiation location of the wafer W, in alternative to or in addition to moving the emission unit140. Thus, it will be understood that the moving unit130may move at least one of the emission unit140or the frame110to change an irradiation location W1of the wafer W to which an inspection electromagnetic wave L1is irradiated by the emission unit140.

As illustrated inFIG.2, the emission unit140may be moved (e.g., by the moving unit130) to a desired inspection location in a first direction D1and a second direction D2, intersecting the first direction D1, using the moving unit130. As illustrated inFIG.3, the entire region (e.g., entire area) of the wafer W may be scanned using the electromagnetic waves L1through such a movement of the emission unit140to analyze transmitted electromagnetic waves (e.g., waves L2detected at the detection unit160) to perform a desired wafer (W) inspection.FIG.3is a plan view ofFIG.2and illustrates an example of the above-described scanning process using the electromagnetic waves.

Referring toFIG.3, wafer inspection may be performed through successive scanning SC from one start point S to an end point F, as indicated by a dotted arrow. However, since electromagnetic waves L1cannot pass through regions of a wafer W, which are in contact with a plurality of vacuum chucks150A1,150A2,150A3,150B1,150B2, and150B3, due to the vacuum chucks150A1,150A2,150A3,150B1,150B2, and150B3, desired analysis may not be performed.

As described above, a region NC, which cannot be analyzed due to a vacuum chuck, may include not only a region, which is in direct contact with the vacuum chuck, but also a neighboring region in which electromagnetic interference may occur.

In order to address such an issue, the plurality of vacuum chucks150A1,150A2, and150A3and150B1,150B2, and150B3, employed in some example embodiments, may be configured to be selectively (for example, for each group) movable between a first location and a second location in the frame110, as described above. Thus, it will be understood that the plurality of vacuum chucks150A1,150A2, and150A3and150B1,150B2, and150B3, employed in some example embodiments, may be configured to be selectively (for example, for each group) movable between a first location and a second location in relation to the frame110.

As shown inFIG.3, the plurality of vacuum chucks may include a first group of vacuum chucks150A1,150A2,150A3and a second group of vacuum chucks150B1,150B2,150B3, where each group includes three vacuum chucks, and where the first and second groups of vacuum chucks include three pairs of adjacent vacuum chucks150A1and150B1,150A2and150B2, and150A3and150B3that are adjacent to each other (e.g., a pair of adjacent vacuum chucks150A1and150B1, a pair of adjacent vacuum chucks150A2and150B2, a pair of adjacent vacuum chucks150A3and150B3).

Since a support surface155of each of the plurality of vacuum chucks150A1,150A2,150A3,150B1,150B2, and150B3in the first location is disposed on (e.g., is coplanar with) a surface for supporting the wafer W (hereinafter referred to as “a reference plane P1”), electromagnetic waves, propagating to a contact region with the wafer W, may be blocked. The “reference plane P1” may be a plane that is coplanar with a rear surface Wb of the wafer W when the wafer W is structurally supported by the frame110, and thus the wafer W may be described as being disposed on and/or supported on the reference plane P1when the wafer W is supported (e.g., structurally supported) by the support structure100.

As shown inFIG.3, the first group of vacuum chucks150A1,150A2, and150A3are configured to be moved to the first location such that the support surfaces155of the plurality of first vacuum chucks150A1,150A2, and150A3are in contact with first contact regions R1of the rear surface Wb of the wafer W, and the plurality of second vacuum chucks150B1,150B2, and150B3are configured to be moved to the first location such that the support surfaces155of the plurality of second vacuum chucks150B1,150B2, and150B3are in contact with second contact regions R2of the rear surface Wb of the wafer W, where the first and second contact regions R1and R2are different regions of the rear surface Wb of the wafer W. As shown inFIG.3, the first and second contact regions R1and R2may be adjacent to each other in pairs on the rear surface Wb of the wafer W.

In some example embodiments, as illustrated inFIG.2, three points (e.g., first contact regions) of the wafer W, which are in contact with the first group of vacuum chucks150A1,150A2, and150A3, and three points (e.g., second contact regions) of the wafer W, which are in contact with the second group of vacuum chucks150B1,150B2, and150B3, may be arranged to be rotationally symmetrical with respect to a center of the wafer (W). The first group of vacuum chucks150A1,150A2, and150A3may be disposed adjacent to the second group of vacuum chucks150B1,150B2, and150B3on each side. As shown, each vacuum chuck of the first group of vacuum chucks150A1,150A2, and150A3and the second group of vacuum chucks150B1,150B2, and150B3is configured to be moved to a first location where the support surface of the respective vacuum chuck being disposed on (e.g., coplanar with) a reference plane P1for supporting the wafer W (e.g., plane P1), such that the support surface155of each vacuum chuck is configured to be disposed on (e.g., coplanar with) the reference plane P1when the vacuum chuck is at the first location.

As described above, the vacuum chucks150A1,150A2, and150A3and150B1,150B2, and150B3of each group may be arranged in appropriate locations of the frame110to support (e.g., structurally support) the wafers W to be inspected in the first location with balance.

In some example embodiments, the plurality of vacuum chucks150A1,150A2,150A3,150B1,150B2, and150B3in the second location may be disposed to deviate from (e.g., move further away from) an electromagnetic wave path, also referred to as a path of the inspection electromagnetic wave L1, between the wafer W and the emission unit140. The vacuum chucks150A1,150A2, and150A3and150B1,150B2, and150B3of the respective groups may be moved from the first location to the second location to reopen (e.g., expose) wafer regions, having been in contact with vacuum chucks, to enable emission unit140to irradiate an inspection electromagnetic wave L1to the exposed wafer regions to enable inspection of the wafer regions. Accordingly, in some example embodiments, among the plurality of vacuum chucks150A1,150A2, and150A3and150B1,150B2, and150B3, a first set of vacuum chucks selectively moved to the first location (e.g.,150A1,150A2, and150A3as shown inFIG.3) may be disposed such that the support surfaces155of the first set of vacuum chuck are coplanar with a plane (e.g., P1) on which the wafer W is disposed, and among the plurality of vacuum chucks150A1,150A2, and150A3and150B1,150B2, and150B3, a second set of vacuum chucks selectively moved to the second location (e.g.,150B1,150B2, and150B3as shown inFIG.3) may be disposed such that the support surfaces155of the second set of vacuum chucks deviate from the path of the inspection electromagnetic wave L1between the wafer W and the emission unit140, for example such that the second set of vacuum chucks do not intersect the path L1-L extending in a vertical direction (e.g., Z-direction) perpendicular to the plane on which the wafer W is disposed and the emission unit140when the emission unit140is aligned with any portion of the wafer W in the vertical direction (e.g., Z-direction). It will be understood that a surface that is described herein as being coplanar with a plane may be substantially coplanar with the plane, such that the surface is coplanar with the plane within manufacturing and/or material tolerances.

There may be various manners of moving a vacuum chuck between the first and second locations. In some example embodiments, the vacuum chucks150A1,150A2,150A3,150B1,150B2, and150B3may each be moved in a flip manner so as to be separated from the reference plane P1to be flipped downwardly in relation to the frame110. In some example embodiments, the vacuum chucks150A1,150A2,150A3,150B1,150B2, and150B3may each be moved in a flip manner so as to be separated from the reference plane P1to descend (e.g., slide downwardly) along the frame110.

For example, the vacuum chucks150A1,150A2,150A3,150B1,150B2, and150B3in the first location may be disposed on internal sidewalls of the frame110to be parallel to the reference plane P1, and a support surface155of a vacuum chuck may face upwardly to be in contact with the wafer W. In some example embodiments, the vacuum chucks150A1,150A2,150A3,150B1,150B2, and150B3in the second location may be flipped below the reference plane P1to be separated from the internal sidewalls of the frame110.

As illustrated inFIGS.4A and4B, the plurality of vacuum chucks150A1,150A2,150A3,150B1,150B2, and150B3may be hingedly connected to a lower end edge of the internal sidewall of the frame110and may be configured to be mechanically driven by the control unit210. Due to the hinge connection, the vacuum chucks150A1,150A2,150A3,150B1,150B2, and150B3may be moved from the first location to the second location and moved again from the second location to the first location.

Referring toFIG.4A, the first group of vacuum chucks150A1,150A2, and150A3may be disposed in the first location, and the second group of vacuum chucks150B1,150B2, and150B3may flipped to be disposed in the second location.

The first group of vacuum chucks150A1,150A2, and150A3may be disposed on the internal sidewalls of the frame110such that the support surface155faces upwardly, and may allow the wafer W to be supported by the support surface155, as illustrated inFIG.3. A wafer W, disposed on the support surface155, may be adsorbed to the support surface155through vacuum suction. In some example embodiments, the second group of vacuum chucks150B1,150B2, and150B3may be flipped vertically downwardly of (e.g., downwardly from) the reference plane P1to deviate from the reference plane P1. Restated, each vacuum chuck of the second group of vacuum chucks150B1,150B2, and150B3may, to be selectively moved to the second location from the first location, flipped vertically and downwardly from the first location, as shown in at leastFIG.4A.

Since the first group (e.g., first set) of vacuum chucks150A1,150A2,150A3may cover a portion (or a support region) of a wafer, they interfere with a path of electromagnetic waves. Meanwhile, the second group of vacuum chucks150B1,150B2, and150B3do not interfere with a path of electromagnetic waves propagating to the wafer W.

Referring toFIG.4B, the second group (e.g., second set) of vacuum chucks150B1,150B2, and150B3may each be moved from a second location to a first location, and the first group of vacuum chucks150A1,150A2, and150A3may each be flipped in the first location to be disposed in the second location. Restated, each vacuum chuck of the second group of vacuum chucks150B1,150B2, and150B3may, to be selectively moved to the first location from the second location, flipped vertically and upwardly from the second location, and each vacuum chuck of the first group of vacuum chucks150A1,150A2, and150A3may, to be selectively moved to the second location from the first location, flipped vertically and downwardly from the first location, as shown in at leastFIG.4B. Accordingly, in view ofFIGS.4A and4B, it will be understood that each vacuum chuck of the first and second groups of vacuum chucks may be configured to be moved to the second location based on being flipped vertically and downwardly from the reference plane P1.

The second group of vacuum chucks150B1,150B2, and150B3may disposed on the internal sidewalls of the frame110such that the support surface155faces upwardly, and may allow the wafer W to be supported by the support surface155. A wafer W, disposed on the support surface155, may be adsorbed to the support surface155through vacuum suction. In some example embodiments, the first group of vacuum chucks150A1,150A2, and150A3may be flipped vertically below the reference plane P1to deviate from the reference plane P1. InFIG.4A, electromagnetic waves may be radiated to portions of the wafer W, covered with the first group of vacuum chucks150A1,150A2, and150A3.

In some example embodiments, as illustrated inFIGS.4A and4B, the internal sidewalls of the frame110may have a seating groove110G corresponding to the vacuum chucks150A1,150A2,150A3,150B1,150B2, and150B3. By assisting in the alignment of the vacuum chucks150A1,150A2,150A3,150B1,150B2, and150B3when they are moved from the second location to the first location, the seating groove110G may secure stable connection of a first channel and a second channel. In addition, the vacuum chuck150A1,150A2,150A3,150B1,150B2, and150B3may be more tightly attached to the seating groove110G of the frame110during a vacuum suction process.

The vacuum chuck150A1, moving in a flip manner, may further move from the second location to a lower surface of the frame110after moving to the second location, as illustrated inFIG.5. For example, the vacuum chuck150A1may move along a rail110R provided on the lower surface of the frame110. Due to such a movement, interference of electromagnetic waves may be more effectively avoided than when disposed in the existing second location (indicated by dotted lines).

As described above, the plurality of vacuum chucks150A1,150A2, and150A3and150B1,150B2, and150B3may be configured for each group to be movable between the first location and a second location in the frame110.

While some example embodiments have been described as an example applied to a transmissive wafer inspection apparatus, some example embodiments may also be advantageously used in another manner (for example, a reflective manner), other than the transmissive manner, even when the measurement is disturbed by a vacuum chuck.

Hereinafter, an electromagnetic wave scanning process for wafer inspection and movement of a vacuum chuck for each group will be described.

FIG.6is a flowchart illustrating a wafer inspection method according to some example embodiments, andFIGS.7A,7B, and7Care plan views for each inspection process, illustrating a wafer inspection method according to some example embodiments.

Referring toFIG.6, a wafer inspection method according to some example embodiments may start with moving the first group of vacuum chucks150A1,150A2, and150A3to a first location and moving the second group of vacuum chucks150B1,150B2, and150B3to a second location (S61).

The first group of vacuum chucks150A1,150A2, and150A3may be disposed on internal sidewalls of the frame110such that a support surface155faces upwardly, whereas the second group of vacuum chucks150B1,150B2, and150B3may be flipped below a reference plane P1on which a wafer W are to be disposed (seeFIGS.4A and7A).

In operation S62, the wafer W may be disposed on the first group of vacuum chucks150A1,150A2, and150A3, and vacuum adsorption of the wafer W may be performed through the first group of vacuum chucks150A1,150A2, and150A3.

Support surfaces155of the first group of vacuum chucks150A1,150A2, and150A3may be in contact with regions of a rear surface Wb of the wafer W, respectively. A wafer W, disposed on the support surface155, may be adsorbed to the support surface155through vacuum suction. Electromagnetic waves cannot pass through such contact regions of the wafer W due to the first group of vacuum chucks150A1,150A2, and150A3(seeFIG.7A).

In operation S64, a first inspection may be performed by scanning the regions of the rear surface Wb of the wafer W, except for contact regions with the first group of vacuum chucks150A1,150A2, and150A3, using electromagnetic waves.

As illustrated inFIG.7A, first scanning51may be performed on regions other than the contact regions with the first group of vacuum chucks150A1,150A2, and150A3(e.g., first contact regions R1). First unscanned regions may include not only the contact regions with the first group of vacuum chucks150A1,150A2, and150A3but also a region adjacent to a contact region in which accurate measurement is not ensured due to interference (.

In operation S66, the second group of vacuum chucks150B1,150B2, and150B3may be moved to the first location, and vacuum suction of the wafer W may be performed through the second group of vacuum chucks150B1,150B2, and150B3.

Thus, the wafer W, on which the first inspection finished to be performed, may be supported by the second group of vacuum chucks150B1,150B2, and150B3together with the first group of vacuum chucks150A1,150A2, and150A3, as illustrated inFIG.7B. This process may be introduced as a process for implementing stable replacement of a vacuum chuck while significantly reducing shake of the wafer W. For example, a vacuum chuck for stably supporting the wafer W without shake of the wafer W may be replaced by performing adsorption using the second group of vacuum chucks150B1,150B2, and150B3while being stably supported by the first group of vacuum chucks150A1,150A2, and150A3.

In operation S68, the first group of vacuum chucks150A1,150A2, and150A3may be moved to the second location after releasing a vacuum mode of the first group of vacuum chucks150A1,150A2, and150A3.

As described above, since the wafer W is vacuum-adsorbed by the second group of vacuum chucks150B1,150B2, and150B3, the first group of vacuum chucks150A1,150A2, and150A3may be moved to the second location, as illustrated inFIG.7C. The first group of vacuum chucks150A1,150A2, and150A3may be flipped below a reference plane P1on which the wafer W is to be disposed (e.g.,FIG.4B).

When such a vacuum chuck is moved, for example, such a vacuum is in contact with the wafer W (for example, moved to the first location) and when separated from the wafer (for example, moved to the second location), it may be moved in a non-parallel direction from the wafer W, in detail, a direction perpendicular to a rear surface Wb of the wafer W to prevent contact and/or collision with the wafer W during movement of the vacuum chuck.

In operation S69, a second inspection is performed by additionally scanning wafer regions unscanned in the first scanning (e.g., the first contact regions R1).

The regions, scanned in this scanning process, may include a region, which was in contact with a vacuum chuck of the first chuck (e.g., first contact regions R1), and a region around the region. This may allow an entire region of a wafer W to be inspected.

As described above, the scanning process may be divided while selectively supporting a wafer using a plurality of movable vacuum chucks. Thus, a desired inspection may be performed up to an edge region of the wafer, and yield of devices in the vicinity of the wafer edge may be significantly improved.

The operations S61-S69may be performed by the wafer inspection apparatus200based on the control unit210causes the wafer inspection apparatus200to perform one or more of said operations. For example, the control unit210may cause the wafer inspection apparatus200to perform a first process (e.g., at least operation S64), in which the emissions unit140and the moving unit130collective cause the inspection electromagnetic wave L1to be irradiated to the rear surface Wb of the wafer W except for at least the first contact regions R1while the first group of vacuum chucks150A1,150A2, and150A3are at the first location and the second group of vacuum chucks150B1,150B2, and150B3are at the second location. In addition, the control unit210may cause the wafer inspection apparatus200to perform a second process (e.g., at least operation S69), in which the emissions unit140and the moving unit130collective cause the inspection electromagnetic wave L1to be irradiated to at least the first contact regions R1(e.g., all regions of the wafer W not irradiated in the first process while the first group of vacuum chucks150A1,150A2, and150A3are at the second location and the second group of vacuum chucks150B1,150B2, and150B3are at the first location. In addition, the control unit210may cause the wafer inspection apparatus200to further perform a process between the first and second processes (e.g., operation S66) which the wafer inspection apparatus200causes the plurality of second vacuum chucks150B1,150B2, and150B3to structurally support the wafer W together with the plurality of first vacuum chucks150A1,150A2, and150A3based on stopping irradiation of the inspection electromagnetic wave L1and moving the plurality of second vacuum chucks150B1,150B2, and150B3to the first location.

The movement of the vacuum chuck and the vacuum adsorption process and the inspection process (for example, the scanning process), illustrated inFIGS.6and7A to7C, may be performed by the control unit (210inFIG.1). In some example embodiments, the plurality of vacuum chucks are described as being divided into two groups, each including three vacuum chucks, and being selectively moved. However, each of the groups may include a different number of vacuum chucks (for example, four vacuum chucks) or may be randomly selected to be individually moved without being divided into a plurality of groups.

In addition, in some example embodiments, the frame is described as a ⊏-shaped structure having three sides, but may have various shapes such as a square and a circle. As described above, the arrangement of the plurality of vacuum chucks and/or the shape of the frame may be variously changed.

FIGS.8and9are plan views of wafer inspection apparatuses according to various example embodiments.

Referring toFIG.8, a wafer inspection apparatus100A according to some example embodiments may include a frame110′ having a rectangular having four sides.

The plurality of vacuum chucks150A1,150A2,150A3,150B1,150B2, and150B3may be divided into first and second groups, each having three vacuum chucks. The first group of vacuum chucks150A1,150A2, and150A3and the second group of vacuum chucks150B1,150B2,150B3include two pairs of vacuum chucks150A2,150A3,150B2, and150B3, disposed adjacent to each other (e.g., two pairs of adjacent vacuum chucks150A2,150A3,150B2, and150B3), and a pair of vacuum chucks150A1and150B1disposed to face each other (e.g., a pair of opposing vacuum chucks150A1and150B1). As illustrated inFIG.8, the two pairs of vacuum chucks150A2,150A3,150B2, and150B3, adjacent to each other, may be respectively disposed on two opposing sides, and the pair of vacuum chucks150A1and150B1may be disposed on two other opposing sides.

The first and second groups of the vacuum chucks150A1,150A2, and150A3and150B1,150B2, and150B3may be disposed to be rotationally symmetrical about a central axis of the wafer W. In some example embodiments, the first group of vacuum chucks150A1,150A2, and150A3may be disposed such that contact points (or first contact regions R1) of the wafer W form a substantially equilateral triangle, and the second group of vacuum chucks150B1,150B2, and150B3may be disposed such that contact point (or second contact regions R1) of the wafer W form a substantially inverted triangle, rotationally symmetrical by 180 degrees with respect to the disposition of the equilateral triangle of the first group of vacuum chucks150A1,150A2, and150A3. Thus, the first and second contact regions R1and R2may be rotationally symmetrical about a central axis W-C of the wafer W.

The disposition of the vacuum chucks, illustrated inFIG.8, may be implemented in a frame having another shape such as a circle. In addition, although vacuum chucks do not necessarily constitute a group, an entire wafer area may be inspected in the same method as the wafer inspection method described with reference toFIG.6.

Referring toFIG.9, a wafer inspection apparatus100B according to some example embodiments may include a circular frame110″ and a plurality of vacuum chucks150A,150B,150C, and150D disposed on the frame110″.

A plurality of vacuum chucks are not basically divided into two groups, and may be randomly combined to replace the selective support by the group described in some example embodiments.

For example, the wafer W is supported by first to third vacuum chucks150A,150B, and150C (a first combination) disposed in a first location, and a first inspection is performed on a wafer region, except for regions in contact with the first to third vacuum chucks150A,150B, and150C, while the wafer is supported by the first combination. Then, the wafer W is supported by first, second, and fourth vacuum chucks150A,150B, and150D (a second combination) disposed in the first location, and a second inspection is additionally performed on a region in contact with the vacuum chuck150C while the wafer W is supported by the second combination.

In a similar manner, third and fourth inspections may be performed on regions in contact with the first and second vacuum chucks150A and150B while the wafer W is supported by the other three vacuum chucks. Thus, the inspection may be performed on the entire area of the wafer W.

Setting of the first and second locations and movement of the first and second locations may be implemented in various forms. In some example embodiments, the vacuum chuck is illustrated as being moved in a flip manner. However, the vacuum chuck may be configured to be moved to the second location, for example, a region not overlapping (e.g., exposed by) a wafer W (for example, a corner region) along a track formed in a frame.

FIGS.10A,10B, and10Care plan views of a wafer inspection apparatus according to some example embodiments, andFIGS.11A,11B, and11Care cross-sectional views illustrating movements of a vacuum chuck of the wafer inspection apparatus illustrated inFIGS.10A,10B, and10C, respectively.

Referring toFIGS.10A and11A, a wafer inspection apparatus according to some example embodiments includes a frame110′ having a rectangular shape and a plurality of vacuum chucks150A1,150A2,150A3,150A4,150B1,150B2,150B3, and150B4disposed on the frame110′. As shown, the frame110′ defines an opening OP that includes multiple corner regions CR that are not covered with the wafer W that is supported by the frame110′, and which may be referred to as corner regions of the opening OP that are exposed by the wafer W supported by the frame110′. Restated, when the frame110′ supports a wafer W, the frame110′ and the wafer W may collectively define corner regions CR that are exposed between the frame110′ and the wafer W.

As illustrated inFIG.10A, the plurality of vacuum chucks150A1,150A2,150A3,150A4,150B1,150B2,150B3, and150B4are divided into first and second groups by four. A first group of vacuum chucks150A1,150A2,150A3, and150A4may be disposed on four sides, respectively. A second group of vacuum chucks150B1,150B2,150B3, and150B4may also be disposed on four sides, respectively. The first group of vacuum chucks150A1,150A2,150A3,150A4support a wafer W in a location adjacent to the center of each side (a first location), while the second group of vacuum chucks150B1,150B2,150B3150B4may be disposed so as not to overlap the wafer W in one or more adjacent corner regions CR on each side (a second location).

Vacuum chucks, employed in some example embodiments, may be moved along the track TRb provided in the frame110′, as illustrated inFIG.11A. The second group of vacuum chucks150B1,150B2,150B3, and150B4may be moved from the first location to the second location along the track TRb. As shown inFIGS.11A-11C, each track of the plurality of tracks TRa and TRb includes a first portion TR-1extending downwardly from the first location, and a second portion TR-2connected to a lower end of the first portion TR-1and extending to the second location in a horizontal direction. The movement of the second group of vacuum chucks150B1,150B2,150B3, and150B4along the track TRb may include a vertical movement L1, in which they are separated from the wafer W in a substantially perpendicular direction, and a horizontal movement L2in which they are moved to the second direction in a horizontal direction. Thus, the second group of vacuum chucks150B1,150B2,150B3, and150B4may be prevented from contacting and/or colliding against the wafer W during the movement to the second location.

As illustrated inFIGS.10B and11B, the second group of vacuum chucks150B1,150B2,150B3and150B4may be moved to the first location along the track TRb provided in the frame110′. Similarly to the operation S64ofFIG.6, this movement may be performed after inspecting a wafer region except for regions in contact with the first group of vacuum chucks150A1,150A2,150A3, and150A4. The second group of vacuum chucks150B1,150B2,150B3and150B4may be moved from the second location to the first location along the track TRb. The movement of the second group of vacuum chucks150B1,150B2,150B3, and150B4along this track TRb may include a reserve horizontal movement L2′, in which they are moved from the second location in a horizontal direction, and a reverse vertical movement L1′ in which they are moved to the first location in a substantially vertical direction. After this movement, similarly to the operation S66ofFIG.6, the wafer may be vacuum-adsorbed by the second group of vacuum chucks150B1,150B2,150B3, and150B4to be supported by the second group of vacuum chucks150B1,150B2,150B3, and150B4together with the first group of vacuum chucks150A1,150A2,150A3, and150A4.

As illustrated inFIGS.10C and11C, the first group of vacuum chucks150A1,150A2,150A3, and150A4may be moved to a second location along a track TRa provided in the frame110′. This movement may be performed by an operation similar to the operation S68ofFIG.6. Specifically, the first group of vacuum chucks150A1,150A2,150A3, and150A4may be moved from the first location to the second location along the track TRa after vacuum suction is released. The movement of the first group of vacuum chucks150A1,150A2,150A3, and150A4along this track TRa may include a vertical movement L1, in which they are separated from the wafer W in a substantially vertical direction, and a horizontal movement L2in which they are moved to the second location in the horizontal direction. Thus, the first group of vacuum chucks150A1,150A2,150A3, and150A4may be prevented from contacting and/or colliding against the wafer W during the movement to the second location. It will be understood that the second location of the first group of vacuum chucks150A1,150A2,150A3, and150A4as shown inFIGS.10C and11C, and the second location of the second group of vacuum chucks150B1,150B2,150B3, and150B4as shown inFIGS.10A and11A, may be in one or more corner regions CR defined between the wafer W and the frame110′. As further shown inFIGS.10A-11C, the frame110′ may include a plurality of tracks TRa and TRb configured to enable the plurality of vacuum chucks to be moveable between the first and second locations.

As shown inFIGS.10A-11C, the plurality of first vacuum chucks150A1,150A2,150A3,150A4and the plurality of second vacuum chucks150B1,150B2,150B3,150B4, in the first location, are adjacent to each other in pairs, and each pair of vacuum chucks, of the plurality of first vacuum chucks150A1,150A2,150A3,150A4and the plurality of second vacuum chucks150B1,150B2,150B3,150B4, in the second location, are disposed in a direction away from the first location, and the frame110′ may include tracks TRa, TRb configured to enable the plurality of vacuum chucks to be movable between the first location and the second location. As shown inFIGS.10A-11C, the plurality of first vacuum chucks150A1,150A2,150A3,150A4and the plurality of second vacuum chucks150B1,150B2,150B3,150B4, when moved to the second location, are in one or more corner regions CR of the plurality of corner regions CR.

As in some example embodiments, a movement of a vacuum chuck using a track may be similarly applied to a frame having a different shape and a vacuum chuck having a different disposition. For example, a vacuum chuck may be moved to a second location (for example, a corner region CR), not overlapping a wafer W, in the support structure illustrated inFIG.3in a manner using a track rather than a flip manner. Additionally, in example embodiments, a movement of a vacuum chuck may be performed by combining the manner using a track with the flip manner. For example, referring toFIG.5, the vacuum chucks may each be configured to be at least partially horizontally moved through a rail or a track provided along a corner of the frame while being flipped, without moving to a lower surface of the frame.

As described above, according to example embodiments, a vacuum chuck may be configured to be movable. Thus, even a portion, covered with the vacuum chuck, may be measured by an additional inspection process. In particular, example embodiments may be advantageously used in a transmissive wafer inspection apparatus.