This application claims priority under 35 U.S.C. §119 to Korean Patent Application No. 10-2014-0125232 filed on Sep. 19, 2014 in the Korean Intellectual Property Office (KIPO), the contents of which are herein incorporated by reference in their entirety.
1. Technical Field
Embodiments of the inventive concepts relate to an apparatus for inspecting a resistive defect of a semiconductor device, in particular a resistive defect of contact plug patterns, and a method of inspecting a resistive defect of a semiconductor device using the apparatus.
2. Description of Related Art
As sizes of circuit patterns of semiconductor devices are reduced, a process of inspecting resistance values of contact plug patterns has become a very important process. Accordingly, not only a process of inspecting whether contact-hole patterns are open or not, but also a process of inspecting resistive defects, that is, determining whether the formed contact plug patterns have an appropriate resistance or not, has become required. Normally, there is a method of inspecting resistive defects by measuring resistances of contact plug patterns using a probe or the like, configured to be in contact with the contact plug patterns or pad patterns connected to the contact plug patterns. However, since sizes of contact plug patterns have become reduced, it has become difficult to inspect the contact plug patterns using a scanning electron microscope (SEM). Further, reliability of a result of the inspection has been significantly decreased.
Some embodiments of the inventive concepts provide a method of inspecting a resistive defect of a semiconductor device.
Some other embodiments of the inventive concepts provide a method of inspecting a contact plug pattern of a semiconductor device.
Still other embodiments of the inventive concepts provide an apparatus for inspecting a resistive defect of a semiconductor device.
Still other embodiments of the inventive concepts provide an apparatus for inspecting a contact plug pattern of a semiconductor device.
In one embodiment, a method of inspecting a resistive defect of a semiconductor device includes loading a semiconductor wafer on a wafer stocker, transferring the semiconductor wafer into an laser anneal module using a transfer module, annealing a portion of the semiconductor wafer using a laser beam in an atmospheric-pressure, transferring the annealed semiconductor wafer into an E-beam scanning module using the transfer module in a vacuum, scanning the annealed portions of the semiconductor wafer with an E-beam, and collecting secondary electrons emitted from the annealed portions of the semiconductor water.
In accordance with another embodiment, a method of inspecting a resistive defect of a semiconductor device includes providing a semiconductor wafer including contact plug patterns, locally annealing portions of the semiconductor wafer to crystallize the contact plug patterns therein, scanning the crystallized contact plug patterns with an E-beam, and collecting secondary electrons emitted from the contact plug patterns scanned with the E-beam.
In accordance with still another embodiment, a method of inspecting a resistive defect of a semiconductor device includes providing an inspecting apparatus including a wafer stocker, a transfer module, an annealing module, a buffer chamber, and an E-beam scanning module, loading a semiconductor wafer including contact plug patterns on the wafer stocker, transferring the semiconductor wafer into the annealing module using a transfer arm of the transfer module, locally annealing portions of the semiconductor wafer in the annealing module to crystallize the contact plug patterns, transferring the semiconductor wafer into the buffer chamber, evacuating the buffer chamber, transferring the semiconductor wafer disposed in the buffer chamber into the E-beam scanning module, scanning the locally-crystallized contact plug patterns of the semiconductor wafer with an E-beam in the E-beam scanning module, collecting secondary electrons from the locally-crystallized contact plug patterns, and displaying a gray-scale image of the contact plug patterns on a monitor according to the amount of the collected secondary electrons.
The foregoing and other features and advantages of the inventive concepts will be apparent from the more particular description of preferred embodiments of the inventive concepts, as illustrated in the accompanying drawings in which like reference numerals denote the same respective parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the inventive concepts. In the drawings:
Various embodiments will now be described more fully with reference to the accompanying drawings in which some embodiments are shown. These inventive concepts may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. The embodiments of the invention are only provided for complete disclosure of the invention and to fully show the scope of the invention to those skilled in the art, and only defined by the scope of the appended claims.
The terminology used herein to describe embodiments of the invention is not intended to limit the scope of the invention. The use of the singular form in the present document should not preclude the presence of more than one referent. In other words, elements of the invention referred to in the singular may number one or more, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including,” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof
It will be understood that when an element is referred to as being “connected to” or “coupled to” another element, it can be connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as “directly connected to” or “directly coupled to” another element or layer, there are no intervening elements or layers present. The term “and/or” includes any and all combinations of one or more referents.
Spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper,” and the like may be used herein to describe the relationship of one element or feature to another, as illustrated in the drawings. It will be understood that such descriptions are intended to encompass different orientations in use or operation in addition to orientations depicted in the drawings.
Embodiments are described herein with reference to a cross-sectional view, a plan view, and/or a block diagram that are schematic illustrations of idealized embodiments and intermediate structures. In addition, in the drawings, the thicknesses of components may be exaggerated or omitted for clarity. Variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments 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.
The same reference numerals denote the same elements throughout the specification. Accordingly, the same numerals and similar numerals can be described with reference to other drawings, even if not specifically described in a corresponding drawing. Further, when a numeral is not marked in a drawing, the numeral can be described with reference to other drawings.
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The wafer stocker 20 may have the shape of a shelf or a table. Semiconductor wafers W to be introduced into the inspecting apparatus 10A or semiconductor wafers W inspected in the inspecting apparatus 10A may be temporarily stocked on/in the wafer stocker 20.
The transfer module 30 may include a transfer arm 31 and/or a wafer station 32. The transfer arm 31 may load and transfer the semiconductor wafers W. For example, the transfer arm 31 may transfer the semiconductor wafers W disposed on/in the wafer stocker 20 to an inside of the laser anneal module 40, transfer the semiconductor wafers W from the laser anneal module 40 to the wafer station 32 or an inside of the buffer chamber 50, or transfer the semiconductor wafers W from the wafer station 32 or the inside of the buffer chamber 50 onto the wafer stocker 20. The wafer station 32 may be disposed in the transfer module 30 to be adjacent to the buffer chamber 50. A semiconductor wafer W1 to be inspected and a semiconductor wafer W2 inspected may be temporarily separated and stocked on the wafer station 32.
The buffer chamber 50 may include a sealable load-lock chamber. The buffer chamber 50 may adjust internal pressure from an atmospheric pressure state to a vacuum state or from a vacuum state to an atmospheric pressure state. The buffer chamber 50 may include an external door 51, an internal door 52, and a buffer transfer arm 53. The buffer transfer arm 53 may transfer the semiconductor wafer W from the transfer module 30 to an inside of the E-beam scanning module 60, or from the E-beam scanning module 60 to the transfer module 30.
For example, when the inside of the buffer chamber 50 is in the atmospheric pressure state, the external door 51 may be opened and the buffer transfer arm 53 may transfer the semiconductor wafer W from the wafer station 32 to the inside of the buffer chamber 50. Then, after the external door 51 is closed and the buffer chamber 50 is sealed and evacuated, the internal door 52 may be opened, the semiconductor wafer W may be transferred to the inside of the E-beam scanning module 60, and the buffer transfer arm 53 may move to the inside of the buffer chamber 50. Then, the internal door 52 may be closed to seal the inside of the E-beam scanning module 60.
After an E-beam scanning process is performed, the internal door 52 may be opened, the buffer transfer arm 53 may transfer the semiconductor wafer W disposed in the E-beam scanning module 60 to the inside of the buffer chamber 50. Then, the internal door 52 may be closed to seal the buffer chamber 50. After the vacuum state of the buffer chamber 50 is released, the external door 51 may be opened and the buffer transfer arm 53 may transfer the semiconductor wafer W onto the wafer station 32 of the transfer module 30.
The laser anneal module 40 and the E-beam scanning module 60 will be described later.
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The laser source 41 may include a laser oscillator. The laser oscillator may include one of a Nd:YAG laser, a Nd:YVO4 laser, a Nd:YLF laser, a Ti:sapphire laser, a He:Ne laser, an IR laser, a green laser, a blue laser, and other various lasers.
The attenuator 42 may adjust energy or amplitude of a laser beam L generated in the laser source 41. The attenuator 42 may include a wavelength converter, a beam shaper, or a shutter. For example, the wavelength converter may uniformize a wavelength of the laser beam L, the beam shaper may form a shape of the laser beam L, and the shutter may output the laser beam L in the form of a continuous wave (CW) or a pulse.
The objective lenses 43A and 43B may have various numerical apertures NAs. Thus, the objective lenses 43A and 43B may variously adjust a beam size of the laser beam L so as to variously define a size of an area which is irradiated by the laser beam L on the semiconductor wafer W in the range of several tens to several hundreds of nanometers. The objective lenses 43A and 43B may be rotated and arranged in a path of the laser beam L.
The semiconductor wafer W may be mounted on the stage 44. The stage 44 may move in up and down, back and forth, and left and right.
The body 61 may have a tube shape. The chamber 66 may be combined to the body 61 to be located under the body 61. Both insides of the body 61 and the chamber 66 may be evacuated.
The E-beam gun 62 may emit an E-beam E1. The condenser lens 63 may adjust a propagation path of the E-beam E1 so that the E-beam E1 is straight without departing from the path. The condenser lens 63 may form an electric field and a magnetic field.
The scanning coil 64 may swing the E-beam E1 back and forth within a predetermined range. The E-beam E1 may be radiated on the semiconductor wafer W in a segment form depending on the scanning coil 64.
The objective lens 65 may focus the E-beam E1 to be radiated on the semiconductor wafer W. The objective lens 65 may also form an electric field and a magnetic field.
The semiconductor wafer W may be mounted on the stage 67. The stage 67 may move in up and down, back and forth, and left and right.
The electron collector 68 may collect secondary electrons E2 emitted from the semiconductor wafer W or recoiled electrons.
The display 69 may include a monitor. The display 69 may display a visual image on the monitor according to the amount of the secondary electrons E2 collected by the electron collector 68. The visual image may include a gray-scale image.
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The laser anneal process may be variously split. For example, the laser anneal process may include irradiating the semiconductor wafer W with the laser beam L having variously split energy. Accordingly, the contact plug patterns 120 may be crystallized to various levels depending on the energy of the radiated laser beam L. The annealed contact plug patterns 120a may have various types of carrier mobility depending on the level of crystallization.
The area of the semiconductor wafer W on which the laser beam L is radiated may be heated to a temperature of about 600 to 850° C. to crystallize the contact plug patterns 120.
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The E-beam scanning process may be performed such that the amount of the secondary electrons E2 is greater than the amount of electrons of the injected E-beam E1. The secondary electrons E2 may be generated mainly from the contact plug patterns 120. The secondary electrons E2 may be differently collected depending on levels of carrier mobility of the contact plug patterns 120. For example, when the contact plug patterns 120 have high carrier mobility, a greater number of secondary electrons E2 may be generated and collected, and when the contact plug patterns 120 have low carrier mobility, a lesser number of secondary electrons E2 may be generated and collected. For example, when the secondary electrons E2 are generated and collected in the electron collector 68 of the E-beam scanning module 60, a potential difference may occur in the contact plug patterns 120. For example, the potential difference may occur due to the difference in concentration of electrons existing in the contact plug patterns 120 and the lower layer 110. Due to the potential difference, electrons may be supplied from the lower layer 110 to the contact plug patterns 120. Accordingly, since relatively more electrons are supplied from the lower layer 110 when the contact plug patterns 120 have high carrier mobility, the contact plug patterns 120 having high carrier mobility may emit relatively more secondary electrons E2.
Accordingly, the difference in electrical conductivity of the contact plug patterns 120 may result in an amplified result according to some of the embodiments.
Next, the method may include displaying the result of inspection in a gray-scale image on the display 69 (S70).
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Depending on a contact area between the contact plug patterns 120 and 120a and the lower layer 110, the contact plug patterns 120 and 120a may have different electrical resistance values. Accordingly, the amount of electrons supplied from the lower layer 110 to the contact plug patterns 120 and 120a may differ depending on the contact resistance values between the contact plug patterns 120 and 120a and the lower layer 110. For example, the contact plug patterns 120 and 120a formed in fully-open contact holes and electrically fully connected to the lower layer 110 among the contact plug patterns 120 and 120a may emit sufficient secondary electrons E2 since electrons are sufficiently supplied from the lower layer 110. The contact plug patterns 120 and 120a formed in partially-open contact holes and electrically partially connected to the lower layer 110 among the contact plug patterns 120 and 120a may partially and limitedly emit secondary electrons E2 since electrons are partially and limitedly supplied from the lower layer 110. The contact plug patterns 120 and 120a formed in not-open contact holes and electrically disconnected to the lower layer 110 among the contact plug patterns 120 and 120a may emit a small amount of secondary electrons E2 since electrons are not supplied from the lower layer 110. Accordingly, the emission amount of the secondary electrons E2 may differ depending on open/not-open conditions of the contact holes and, more specifically, depending on states of electrical and physical connection between the contact plug patterns 120 and 120a and the lower layer 110.
According to some of the embodiments, since electrical resistances of the laser-annealed contact plug patterns 120a are low, free electrons may more easily move from the lower layer 110 to the contact plug patterns 120 and 120a. Accordingly, not only open/not-open conditions of the contact plug patterns 120 and 120a but also a more difference in electrical resistances of the contact plug patterns 120 and 120a may be shown.
According to some of the embodiments, productivity of a semiconductor device may be improved. Since a coil-type heater or a halogen lamp is used in a process of annealing the entire semiconductor wafer W and inspecting the annealed semiconductor wafer W, a long process time for annealing the semiconductor wafer W may be required. In addition, productivity may be lowered since an inspected semiconductor wafer W is eliminated. According to some of the embodiments, a process time may be very short since only a part of the semiconductor wafer W is heated using a laser. In addition, since only a locally annealed portion of the semiconductor wafer W is eliminated, the other portions of the semiconductor wafer W may be used as a normal product.
According to some of the embodiments, since a resistive defect of a semiconductor device may be detected as an amplified result, inspection may be more precise.
According to some of the embodiments, only a part (parts of chips) of a semiconductor wafer may be consumed since the part of the semiconductor wafer is annealed and scanned with E-beam. According to some of the embodiments, the amount of time spent on the inspection process may be reduced by using an integrated inspecting apparatus. Accordingly, productivity may increase and product costs may decrease.
Although a few embodiments have been described, those skilled in the art will readily appreciate that many modifications are possible without materially departing from the novel teachings and advantages. Accordingly, all such modifications are intended to be included within the scope of this inventive concepts as defined in the claims.
Number | Date | Country | Kind |
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10-2014-0125232 | Sep 2014 | KR | national |