KR20040096275A - Method for detecting defect of wafer and apparatus for performing the same - Google Patents

Abstract

PURPOSE: A method and an apparatus for inspecting a defect of a wafer surface are provided to optimize processing conditions by detecting defects of an entire surface of a wafer including the pattern region and the other region. CONSTITUTION: A wafer loading process is performed to load a wafer into an inside of a wafer inspection unit in order to prepare a wafer inspection process(S100). A wafer measurement condition setup process is performed to set up wafer measurement conditions(S110). An inspection process is performed to measure simultaneously the pattern region and the other region according to the wafer measurement conditions in order to detect a defect of an entire surface of a wafer(S120).

Description

Method for detecting defect of wafer and apparatus for performing the same

The present invention relates to a method for inspecting a wafer surface using a wafer inspection tool, and more particularly, to an inspection method and an inspection apparatus for defects on a wafer surface in which a manufacturing process is in progress or a manufacturing process is completed. It is about.

With the recent increase in the degree of integration of semiconductor devices, the presence of particles, voids, dislocations, stacking faults, and interface faults, which are a kind of defects, It has become an important factor influencing the electrical characteristics and performance of semiconductor devices.

The size of a unit device realized on a silicon single crystal substrate is gradually being reduced. Accordingly, the critical dimension (CD) of each component constituting the unit device must also be controlled in micro units.

In particular, in the case of a memory device, the thickness of the oxide forming the gate dielectric layer must be finely controlled, and the thickness of the thin film must be extremely fine in order to increase capacitance and obtain uniform electrical characteristics even in the storage dielectric layer formed on the storage node. And maintain a uniform thickness in atomic units. Even in non-memory devices that realize high-speed operation, the dimensions of the components constituting each transistor are continuously being reduced.

The presence of defects in such a microstructured semiconductor device degrades or causes malfunctions of transistors, capacitors, metallization, and pads to realize electrical connections within the semiconductor device.

Therefore, in the manufacturing process of the semiconductor device, defects on the surface are inspected and measured during or after completion of the process. The defect measurement is limited to the area where the pattern is formed on the wafer, and the light component is irradiated at a predetermined angle on the wafer surface to analyze the light component scattered from the surface to examine the existence of the defect and the type of the defect. do.

As such, the wafer surface inspection is performed only in the pattern region in which the pattern of the semiconductor device is formed, and the inspection of the non-pattern region, which is the region where the pattern is not formed, is not performed. However, recent research has shown that defects in edge portions of wafers or non-patterned regions where patterns are not formed affect the portions where patterns are formed. Being added.

However, in the wafer surface inspection, the inspection of the non-patterned region is not performed, so that defect analysis and feed back to the manufacturing process, which are inherent in the inspection, are not completely performed.

An object of the present invention for solving the above problems is to provide a defect inspection method and inspection apparatus for the entire wafer surface including a pattern region and a non-pattern region.

1 is a plan view showing a pattern region and a non-pattern region on a wafer.

2 is a schematic diagram of an apparatus for detecting a defect on a wafer.

3 is a plan view of an image of a wafer in which defect inspection is completed according to the present invention.

4 is a flow chart showing an embodiment of a wafer defect inspection method.

5 is a flow chart showing another embodiment of a wafer defect inspection method.

Explanation of symbols on the main parts of the drawings

100 wafer 110 pattern region

120: non-pattern area 200: inspection unit

210: irradiation unit 220: detection unit

230: wafer support portion 240: inspection space

250: input unit 260: display unit

270: central processing unit 300: defects on the wafer

The present invention comprises the steps of loading the wafer into the inspection means to prepare for inspection; Setting measurement conditions of the wafer; And simultaneously detecting the pattern region and the non-pattern region according to the measurement conditions to detect defects on the entire surface of the wafer.

In addition, the present invention includes a means for preparing the inspection by loading the wafer into the inspection means; Setting a preliminary measurement condition for inspecting the wafer, inspecting the wafer using the preliminary measurement condition, and determining whether the preliminary measurement condition is suitable for the wafer based on a result of inspecting the wafer; Means for correcting the preliminary measurement conditions based on a result to set measurement conditions of the pattern area; And means for inspecting the pattern region and the non-pattern region simultaneously according to the measurement conditions to detect defects on the entire surface of the wafer.

According to the present invention, defects can be easily inspected for the entire wafer surface including the pattern region and the non-pattern region on the wafer.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the present invention will be described as an example of the KLA-TENCOR 2350 device of KLA-TENCOR company among various types of inspection apparatus, it will be appreciated by those skilled in the art that the recipe preparation method according to the present invention can be easily applied to other devices.

1 is a plan view showing a pattern region and a non-pattern region on a wafer.

Referring to FIG. 1, a pattern region 110 in which semiconductor devices are positioned at regular intervals and a non-pattern region 120 in which no pattern is formed are illustrated.

First, the wafer 100 to be inspected is loaded into the inspection space of the inspection apparatus. With the loading of the wafer 100, an inspection apparatus recognizes an edge portion of the wafer 100 through a sensor to align the wafer 100 in a predetermined orientation, and the wafer 100 is in a test ready state in the test space. I will wait. The sensor is preferably an optical sensor. Subsequently, measurement conditions are created according to the state of the wafer 100, which is called a recipe creation process. That is, the recipe may be referred to as an algorithm for instructing and determining the operation mode of the inspection apparatus in wafer inspection.

In preparing the above recipe, measurement conditions are first set. As the measurement conditions, the brightness of the irradiation means is specified. The irradiation means may include a lamp having a wavelength in the visible light region, or may be in the form of an electron beam or a laser beam that travels in a straight line at high speed. Preferably the shape of the laser beam is suitable. The laser beam is light whose wavelength and phase match, and unlike ordinary light, the laser beam has a property that dispersion does not occur regardless of the characteristics of the medium.

In addition, a comparison area is designated by the measurement conditions. This may be set differently according to the surface state of the wafer, and the pattern region 110 performs defect inspection by comparing the pattern regions 110, and the non-pattern region 120 is compared with the non-pattern region 120. It is to carry out defect inspection.

In addition, the focus of the light source irradiated to the wafer to be inspected is specified. By designating the focus, the inspection apparatus determines an incident angle and a detection angle with respect to the wafer to perform defect inspection on the wafer surface. In addition, the area in which the light source irradiates the wafer is determined according to the designated value of the focus. The light source scans the wafer surface while keeping the irradiation area constant. A preferred form of scanning is similar to the irradiation form of an analog television receiver, after irradiating a horizontally constant first area and then moving it in a diagonal direction to a second area at the bottom of the first area so that the second area is the same as the first area irradiation. Take the form of irradiation in the direction.

As another condition of the measurement condition setting, an error range between color differences is determined. This is for the inspection apparatus to determine the defect of the wafer for the color difference outside the predetermined range. However, this value is variable depending on the type and condition of the wafer to be inspected and the conditions of the inspection apparatus, and thus may be set differently according to the wafer and the inspection apparatus.

As described above, when the setting of the measurement conditions of the wafer to be inspected is completed, the actual measurement of the surface of the wafer is performed. Preferably the wafer is suitably a standard wafer. That is, a reference wafer having a defect already present at a predetermined position is measured to compare whether the actually measured defects coincide with the defects of the reference wafer.

Preferably, if there is a difference in the comparison result, the measurement conditions are reset. That is, the process of setting the optimum inspection conditions for the wafer to be inspected through the feedback.

Once this is done, the recipe is final. In a typical recipe preparation process, a care area should be designated, but according to the present invention, the care area is not required. The care area refers to a specific area on the wafer which is recognized by the inspection apparatus and inspected in the wafer defect inspection.

In the final step, the inspection apparatus performs defect inspection on the wafer according to the final recipe.

2 is a schematic diagram of an inspection apparatus showing a process of detecting a defect on a wafer.

Referring to FIG. 2, there is a wafer 100 loaded into the inspection space 240 of the inspection unit 200 and positioned on the wafer support 230 and aligned in a predetermined orientation.

The recipe prepared and prepared by the input unit 250 is stored, calculated, and processed by the central processing unit 270, and the irradiation unit 210, the detector 220, and the wafer support unit 230 in the inspection unit 200 are predetermined. Control them to play a role.

In the inspection process, when the irradiation unit 210 serves as a light source and irradiates light to a specific position on the surface of the wafer 100 that is in the inspection standby state in the inspection space 240 at a predetermined incident angle, the wafer surface reflects the light. The reflected light is detected by the detector 220 located in the upper space of the wafer 100 to determine whether a defect is present. If it is determined that the defect exists, the central processing unit 270 processes it as an image signal and sends it to the display unit 260. The display unit 260 images and outputs the received image signal so as to be visually identified.

If this process is repeated for the entire wafer, the result as shown in FIG. 3 is obtained.

3 is a plan view of an image of a wafer in which defect inspection is completed according to the present invention.

3 shows defects 300 present throughout the wafer as a top view of the image of the wafer upon which defect inspection has been completed. The defects may be particles, voids, dislocations, stacking faults, interface faults, and the like. Particles and voids are classified as point defects, and dislocations are classified as predecessors. The dislocation may be generated by external tension or stress in the single crystal, or may be formed in a process in which internal energy in the crystal escapes. Lamination defects and interface defects are classified as defects, which are caused by other factors in the direction of crystal growth in a single crystal, or due to mismatch in an interface phase.

4 is a flow chart showing an embodiment of a wafer defect inspection method. Referring to FIG. 4, the inspection target wafer is loaded into the inspection space 240 in the inspection apparatus (S100). The wafer is supported by the support 230 to be ready for inspection. Next, a measurement condition is set (S110), and the brightness of the irradiation means, the comparison area, the error range between the focus and the color difference, and the like can be specified. Then, the measurement conditions are input to the central processing unit 270 through the input unit 250 to prepare a final recipe. According to the final recipe, the inspection unit 200 performs an inspection (S120) on the pattern region and the non-pattern region of the wafer.

In the inspection process, when the irradiation unit 210 serves as a light source and irradiates light to a specific position on the surface of the wafer 100 that is in the inspection standby state in the inspection space 240 at a predetermined incident angle, the wafer surface reflects the light. The reflected light is detected by the detector 220 located in the upper space of the wafer 100 to determine whether a defect is present. For example, if there is a defect on the surface of the wafer 100, light scattering occurs on the surface of the wafer 100, so that a difference occurs when the intensity and wavelength of the light detected by the detector 220 do not have a defect. The difference detected by the detection unit 220 determines that a defect exists at a specific position on the wafer in the central processing unit 270, and the central processing unit 270 processes the image signal as an image signal and sends it to the display unit 260. The display unit 260 images and outputs the received image signal so as to be visually identified.

5 is a flow chart showing another embodiment of a wafer defect inspection method. Referring to FIG. 5, the inspection target wafer is loaded into the inspection space 240 in the inspection apparatus (S200). The wafer is supported by the support 230 to be ready for inspection. Next, a preliminary measurement condition is set (S210), and the brightness of the irradiation means, the comparison area, the error range between the focus and the color difference, etc. can be specified. Subsequently, inspection of the wafer under the preliminary measurement conditions set (S220) is performed. Thereafter, it is determined whether the set preliminary measurement condition is suitable for the wafer to be inspected (S230). If the measurement conditions are not suitable for the wafer, the preliminary measurement conditions are corrected and input again (S210). If it is determined that the preliminary measurement condition is suitable for the wafer to be inspected, the measurement condition is prepared through the input unit 250 (S240) and input to the central processing unit 270. According to the measurement conditions, the inspection unit 200 performs inspection (S250) on the pattern region and the non-pattern region of the wafer.

In the inspection process, when the irradiation unit 210 serves as a light source and irradiates light to a specific position on the surface of the wafer 100 that is in the inspection standby state in the inspection space 240 at a predetermined incident angle, the wafer surface reflects the light. The reflected light is detected by the detector 220 located in the upper space of the wafer 100 to determine whether a defect is present. For example, if there is a defect on the surface of the wafer 100, light scattering occurs on the surface of the wafer 100, so that a difference occurs when the intensity and wavelength of the light detected by the detector 220 do not have a defect. The difference detected by the detection unit 220 determines that a defect exists at a specific position on the wafer in the central processing unit 270, and the central processing unit 270 processes the image signal as an image signal and sends it to the display unit 260. The display unit 260 images and outputs the received image signal so as to be visually identified.

When the inspection of the pattern region and the non-pattern region of the wafer as described above is performed on the entire wafer, it is possible to grasp the distribution and types of defects present on the surface.

As a result, the defects in the non-patterned region and the defects in the pattern region measured by the detection unit of the inspection apparatus and output to the display unit are fed back in a unit process to set an optimal process condition according to the type of semiconductor device.

According to the present invention as described above, defects can be inspected for the entire wafer surface including the pattern region and the non-pattern region on the wafer.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

Claims (11)

Loading the wafer into inspection means to prepare for inspection; Setting measurement conditions of the wafer; And And inspecting the pattern region and the non-pattern region simultaneously according to the measurement conditions to detect defects on the entire surface of the wafer. The method of claim 1, wherein the detecting of the defect Irradiating light onto the entire wafer; Reflecting the irradiated light beam from the wafer; Detecting light rays reflected from the wafer; Converting the detected light rays into quantified measurements; And And determining the defect by comparing the converted measured value with a reference value. The method of claim 2, wherein the measurement condition comprises designating a brightness of the light beam, a comparison area, a focus of the light beam, and a color difference error range of the light beam. The method of claim 2, wherein the light beam is a lamp light, an electron beam, or a laser beam. The method of claim 1, wherein the wafer is a reference wafer having a defect programmed in a predetermined position. The method of claim 1, wherein the defect is a particle, void, dislocation, lamination defect, or interface defect. The method of claim 1, wherein the setting of the measurement conditions Setting preliminary measurement conditions for inspecting the wafer; Inspecting the wafer using the preliminary measurement conditions; Determining whether the preliminary measurement conditions are suitable for the wafer based on a result of inspecting the wafer; And And correcting the preliminary measurement conditions and setting the measurement conditions based on the determination result. The method of claim 7, wherein correcting the preliminary measurement conditions Resetting the preliminary measurement condition if the preliminary measurement condition is not suitable for the wafer; Retesting the wafer using the reset preliminary measurement condition; And determining whether the reset preliminary measurement condition is suitable for the wafer based on a result of the re-inspection of the wafer. The method of claim 7, wherein And if the preliminary measurement conditions are suitable for the wafer, setting the preliminary measurement conditions to the measurement conditions. Means for loading the wafer into inspection means to prepare for inspection; Setting a preliminary measurement condition for inspecting the wafer, inspecting the wafer using the preliminary measurement condition, and determining whether the preliminary measurement condition is suitable for the wafer based on a result of inspecting the wafer; Means for correcting the preliminary measurement conditions based on a result to set measurement conditions of the pattern area; And And means for inspecting the pattern region and the non-pattern region simultaneously according to the measurement conditions to detect defects on the entire surface of the wafer. 11. The apparatus of claim 10, wherein the means for detecting the defect is Means for irradiating light onto the entire wafer; Means for detecting light rays reflected from the wafer; Means for converting the detected light rays into quantified measurements; And And means for determining the defect by comparing the converted measurement value with a reference value.