CN113921413A - Wafer placement state detection method and semiconductor process chamber - Google Patents

Wafer placement state detection method and semiconductor process chamber Download PDF

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Publication number
CN113921413A
CN113921413A CN202111158669.XA CN202111158669A CN113921413A CN 113921413 A CN113921413 A CN 113921413A CN 202111158669 A CN202111158669 A CN 202111158669A CN 113921413 A CN113921413 A CN 113921413A
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wafer
chuck
height
abnormal
preset
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Chinese (zh)
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程壮壮
宋爱军
张朝轩
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Beijing Naura Microelectronics Equipment Co Ltd
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Beijing Naura Microelectronics Equipment Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L22/00—Testing or measuring during manufacture or treatment; Reliability measurements, i.e. testing of parts without further processing to modify the parts as such; Structural arrangements therefor
    • H01L22/10—Measuring as part of the manufacturing process
    • H01L22/12—Measuring as part of the manufacturing process for structural parameters, e.g. thickness, line width, refractive index, temperature, warp, bond strength, defects, optical inspection, electrical measurement of structural dimensions, metallurgic measurement of diffusions
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/683—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L21/687—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using mechanical means, e.g. chucks, clamps or pinches
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/683—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L21/687—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using mechanical means, e.g. chucks, clamps or pinches
    • H01L21/68714—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using mechanical means, e.g. chucks, clamps or pinches the wafers being placed on a susceptor, stage or support

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Container, Conveyance, Adherence, Positioning, Of Wafer (AREA)

Abstract

The invention provides a wafer placement state detection method, which is used for detecting the fixed state of a wafer on a wafer chuck and comprises the following steps: controlling the wafer chuck to drive the wafer to rotate at a preset rotating speed; acquiring a height value along the axial direction at a preset position on the surface of the wafer at a preset distance from the axis of the wafer chuck; and judging whether the fixed state of the wafer is abnormal or not according to the change situation of the height value. The wafer placement state detection method provided by the invention detects the height of the preset position deviating from the axis of the wafer chuck on the surface of the wafer, so that the abnormal fixing state of the wafer can be found in time, the wafer is prevented from falling out to cause fragments in the high-speed rotation process, the safety of a semiconductor process is further improved, and the service life of semiconductor process equipment is prolonged. The invention also provides a semiconductor process chamber.

Description

Wafer placement state detection method and semiconductor process chamber
Technical Field
The invention relates to the field of semiconductor process equipment, in particular to a wafer placement state detection method and a semiconductor process chamber.
Background
In the single wafer cleaning equipment, the chuck plays a role of bearing and fixing the wafer, the chuck needs to hold the wafer to rotate in the process, and once the wafer is not sufficiently fixed, the wafer can be thrown out of the chuck to cause fragments when the chuck rotates at a high speed. The debris not only causes irreparable losses to the product, but also causes some damage to the equipment. Therefore, it is necessary to detect the clamping of the wafer before the chuck rotates at a high speed to prevent the occurrence of chipping.
Disclosure of Invention
The invention aims to provide a wafer placement state detection method and a semiconductor process chamber, wherein the wafer placement state detection method can identify whether the fixed state of a wafer is abnormal or not, avoid fragments caused by the separation of the wafer in the high-speed rotation process, further improve the safety of a semiconductor process and prolong the service life of semiconductor process equipment.
In order to achieve the above object, according to an aspect of the present invention, there is provided a wafer placement state detecting method for detecting a fixing state of a wafer on a wafer chuck, the detecting method including:
controlling the wafer chuck to drive the wafer to rotate at a preset rotating speed;
acquiring a height value along the axial direction at a preset position on the surface of the wafer, wherein the preset distance is away from the axis of the wafer chuck;
and judging whether the fixed state of the wafer is abnormal or not according to the change situation of the height value.
Optionally, the obtaining a height value of the surface of the wafer at a predetermined position from the axis of the wafer chuck along the axial direction includes:
acquiring a plurality of ranging values at a preset frequency through a ranging sensor above the wafer chuck;
calculating difference values between a reference value and the plurality of distance measurement values respectively to obtain a plurality of height values; the reference value is the maximum distance measurement result of the distance measurement sensor for measuring the distance of the bearing surface of the wafer chuck.
Optionally, the determining whether the wafer is in an abnormal fixed state according to the variation of the height value includes:
and selecting the maximum value and the minimum value in the plurality of height values, calculating the range difference between the two extreme values, and judging that the wafer is abnormal in the fixed state if the range difference is greater than a first preset threshold value.
Optionally, the first preset threshold is 0.2mm to 0.5 mm.
Optionally, the determining whether the wafer is in an abnormal fixed state according to the variation of the height value includes:
and calculating the average value of the plurality of height values, and if the average value exceeds a preset fluctuation range, judging that the wafer is abnormal in the fixed state.
Optionally, the preset fluctuation range is: greater than 0.3mm and less than 0.6 mm.
Optionally, the determining whether the wafer is in an abnormal fixed state according to the variation of the height value includes:
and calculating the variance of the plurality of height values, and if the variance is larger than or equal to a second preset threshold value, judging that the wafer is abnormal in the fixed state.
Optionally, the second preset threshold is 0.01mm to 0.05 mm.
Optionally, the predetermined position is located in a projection range of the wafer on the carrying surface, and the predetermined position is 2mm to 3mm away from an edge of the wafer.
As a second aspect of the present invention, a semiconductor process chamber is provided, where the semiconductor process chamber includes a cavity and a wafer chuck disposed in the cavity, the wafer chuck is configured to fix a wafer received from an outside of the process chamber through a carrying surface and drive the wafer to rotate around an axis of the wafer chuck, and the process chamber further includes a wafer detection assembly configured to detect a fixing state of the wafer on the wafer chuck according to the wafer placement state detection method.
Optionally, the wafer detection assembly comprises a distance measuring sensor and a sensor fixing frame, the sensor fixing frame comprises a beam guide rail, two ends of the beam guide rail are respectively fixed on the inner walls of two sides of the cavity, the beam guide rail passes through the upper portion of the wafer chuck, the distance measuring sensor is arranged on the beam guide rail and can be moved along the beam guide rail.
Optionally, the wafer detection assembly further comprises a connecting sleeve, the connecting sleeve is arranged on the beam guide rail in a surrounding mode, the end portion of the connecting sleeve is connected with the distance measuring sensor, and the two ends of the connecting sleeve are connected through a fastening piece.
In the wafer placement state detection method and the semiconductor process chamber provided by the invention, the wafer detection assembly can detect the height of the preset position deviating from the axis of the wafer chuck on the surface of the wafer, so that the abnormal fixing state of the wafer can be found in time, the wafer is prevented from falling out to cause fragments in the high-speed rotation process, the safety of the semiconductor process is improved, and the service life of semiconductor process equipment is prolonged.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
FIG. 1 is a top view of a relative positional relationship between a chuck and a sensor in a conventional single wafer cleaning apparatus;
FIG. 2 is a front view of the relative positional relationship between the chuck and the sensor in the conventional single wafer cleaning apparatus;
FIG. 3 is a perspective view of the relative position between the chuck and the sensor in a conventional single wafer cleaning apparatus;
FIG. 4 is a schematic flow chart of a wafer cleaning process performed by a conventional single wafer cleaning apparatus;
FIG. 5 is a schematic diagram of a semiconductor processing chamber according to an embodiment of the present invention;
FIG. 6 is a schematic view of a semiconductor processing chamber with a wafer not flat on a wafer chuck according to an embodiment of the present invention;
FIG. 7 is a schematic diagram of a positional relationship between a ranging sensor and a wafer chuck in a semiconductor processing chamber according to an embodiment of the present invention;
FIG. 8 is a perspective view of a ranging sensor and a wafer chuck in a semiconductor processing chamber according to an embodiment of the present invention;
FIG. 9 is a flowchart illustrating a wafer transfer method according to an embodiment of the present invention;
FIG. 10 is a schematic diagram illustrating a wafer cleaning process performed in a semiconductor processing chamber according to an embodiment of the present invention;
FIG. 11 is a schematic view of a state of a clamping jaw on a wafer chuck in a semiconductor processing chamber provided by an embodiment of the present invention;
figure 12 is a schematic view of another state of a clamping jaw on a wafer chuck in a semiconductor processing chamber according to an embodiment of the present invention.
Detailed Description
The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.
Fig. 1 to 3 are schematic views illustrating a conventional single wafer cleaning apparatus including a robot (not shown) for transferring a wafer into or out of a process chamber, a chuck 20 disposed in the process chamber, and a sensor 30 disposed above the chuck 20. Wherein the sensor 30 is generally disposed at a position where the axis of the chuck 20 passes, i.e., the projection in the horizontal plane is located at the center of the chuck 20 and the wafer 10, for detecting whether the wafer 10 is present on the chuck 20. As shown in fig. 4, in the conventional wafer cleaning process, after a robot places a wafer 10 on a chuck 20 and a clamping jaw 21 on the chuck 20 is folded from the periphery to the center (to clamp the wafer), a sensor 30 detects whether the wafer 10 is on the chuck, after detecting the wafer 10, the chuck 20 rotates and performs the process, and if the wafer 10 is not detected, the process is stopped and an alarm is given.
After research, the inventor of the present invention found that the chipping problem in the conventional single wafer cleaning apparatus is often caused by insufficient levelness of the wafer 10, that is, the wafer 10 is not leveled, so that the force applied between the wafer 10 and the clamping jaw after the clamping jaw is folded toward the center (as shown in fig. 6 and 7) is not uniform in the circumferential direction, and the wafer 10 is thrown out when the chuck 20 rotates at a high speed.
However, the conventional solution can only detect the presence or absence of the wafer 10, and cannot further determine whether the wafer 10 is flat, so that it is difficult to prevent the chipping phenomenon.
In order to solve the above technical problem, as an aspect of the present invention, a wafer placement state detecting method is provided for detecting a fixing state of a wafer 10 on a wafer chuck 200, as shown in fig. 5, a semiconductor process chamber includes a chamber 100 and the wafer chuck 200 disposed in the chamber 100, the wafer chuck 200 is configured to fix the wafer 10 received from an outside of the semiconductor process chamber through a carrying surface and drive the wafer 10 to rotate around an axis of the wafer chuck 200, and the semiconductor process chamber further includes a wafer detecting assembly for performing the detecting method. The detection method comprises the following steps:
step S1, controlling the wafer chuck 200 to drive the wafer 10 to rotate at a predetermined rotation speed;
step S2, obtaining a height value along the axial direction at a predetermined position on the surface of the wafer 10 at a predetermined distance from the axis of the wafer chuck 200;
step S3, determining whether the wafer 10 is in an abnormal fixed state according to the change of the height value.
It should be noted that the predetermined position refers to a position fixed relative to the chamber 100 (and the axis of the wafer chuck 200) in a horizontal plane projection, and is not a fixed position on the surface of the wafer 10 or the wafer chuck 200, and the predetermined position does not move with the rotation of the wafer 10 or the wafer chuck 200.
The wafer placement state detection method provided by the invention can determine whether the fixing state of the wafer 10 is abnormal or not by detecting the height of the predetermined position on the surface of the wafer 10 deviated from the axis of the wafer chuck 200. Specifically, under the condition that the wafer 10 is normally laid flat and fixed, the height of the surface passing through the predetermined position does not change significantly when the wafer 10 rotates, and when the surface of the wafer 10 inclines (i.e. the condition shown in fig. 6), the tilted side (i.e. the right side of the wafer 10 in fig. 6) and the downward-inclined side (i.e. the left side of the wafer 10 in fig. 6) rotate to the predetermined position alternately along with the rotation of the wafer 10, and the height detection result of the wafer detection assembly on the predetermined position of the surface of the wafer 10 changes accordingly, so that the abnormal fixing state of the wafer 10 can be found in time, the wafer 10 is prevented from falling out to cause fragments in the high-speed rotation process, the safety of the semiconductor process is improved, and the service life of the semiconductor process equipment is prolonged.
The embodiment of the invention does not specifically limit how to detect the height value of the preset position on the surface of the wafer 10 along the axial direction, for example, the height value can be detected by an elastic detection mechanism, the elastic detection mechanism is in rolling contact with the surface of the wafer 10, and a contact point vibrates up and down along with the rotation of the wafer 10, so that the height change condition of the preset position on the surface of the wafer 10 is detected based on the mechanical transmission principle; alternatively, the wafer 10 may be continuously photographed by a camera module disposed on the sidewall of the chamber 100 to record the undulation of the surface of the wafer 10.
In order to ensure the integrity of the surface structure of the wafer 10 and the circumferential uniformity of the internal structure of the chamber, as a preferred embodiment of the present invention, as shown in fig. 5, the wafer inspection assembly includes a distance measuring sensor 300 located above the wafer chuck 200, and the projection of the distance measuring sensor 300 on the horizontal plane is consistent with the projection position of the predetermined position on the horizontal plane. Acquiring a height value in an axial direction at a predetermined position from an axis of the wafer chuck 200 on a surface of the wafer 10, includes:
acquiring a plurality of height values at a preset frequency through the ranging sensor 300;
it should be noted that the distance measuring sensor 300 is an optical distance measuring sensor 300, for example, the distance measuring sensor 300 may be an infrared distance measuring sensor 300. The distance measuring sensor 300 can measure the distance based on an optical principle, that is, the distance measuring sensor 300 emits a beam of light to the object to be measured and receives the light reflected by the object to be measured, and the distance between the distance measuring sensor 300 and the object to be measured can be obtained according to the propagation speed of the light and the time difference of the back-and-forth propagation of the light.
The embodiment of the present invention does not specifically limit the specific orientation of the predetermined position on the surface of the wafer 10, for example, to improve the feedback of the height variation of the tilt angle of the wafer 10 at the predetermined position on the surface of the wafer 10, the predetermined position may be the edge of the wafer 10. In order to prevent the wafer 10 from being tilted so that a part of the edge does not pass through the predetermined position during rotation, as shown in fig. 6 to 8, the predetermined position is located within a projection range of the wafer 10 on the carrying surface, and the predetermined position is 2mm to 3mm away from the edge of the wafer 10.
Under the condition that the material deposited on the front surface of the wafer has high sensitivity to light, in order to prevent the light above the process chamber from influencing the front surface pattern of the wafer 10, the wafer 10 can be placed on the wafer chuck 200 with the front surface facing downwards and the back surface facing upwards; in order to prevent the distance measuring sensor 300 from affecting the material deposited on the front surface of the wafer 10, in this case, the predetermined position is preferably set outside the effective pattern range of the front surface of the wafer 10 (i.e. 2mm to 3mm from the edge of the wafer 10) in the embodiment of the present invention, so as to prevent the infrared light emitted by the distance measuring sensor 300 from directly irradiating the front surface pattern of the wafer 10, thereby ensuring the integrity of the front surface pattern of the wafer 10.
The embodiment of the present invention does not specifically limit how to fix the ranging sensor 300 in the chamber 100, for example, as an alternative embodiment of the present invention, as shown in fig. 5, the wafer inspection assembly further includes a sensor holder 110 disposed in the chamber 100, and the ranging sensor 300 is disposed on the sensor holder 110.
In order to facilitate the adjustment of the position of the distance measuring sensor 300 for wafers of different sizes, as a preferred embodiment of the present invention, as shown in fig. 5, the sensor holder 110 includes a beam guide, both ends of which are respectively fixed on both side inner walls of the chamber 100, and the beam guide passes over the wafer chuck 200, and the distance measuring sensor 300 is disposed on the beam guide and can move along the beam guide.
In the embodiment of the present invention, the beam guide passes over the wafer 10, and the distance measuring sensor 300 is disposed on the beam guide and can move along the beam guide, so that when the wafer size is changed, the position of the distance measuring sensor 300 on the beam guide can be moved again, so that a certain distance (e.g., 3mm) is formed between a predetermined position of the distance measuring sensor 300 corresponding to the surface of the wafer 10 (i.e., the projection position of the distance measuring sensor 300 on the surface of the wafer 10) and the edge of the wafer 10, thereby improving the adaptability of the chamber 100 to wafers of different sizes.
In order to facilitate the switching between the fixed state and the unfixed state of the distance measuring sensor 300 and the crossbeam guide rail, as a preferred embodiment of the present invention, as shown in fig. 5, the distance measuring sensor 300 is connected with the crossbeam guide rail through a connecting sleeve 111, specifically, the connecting sleeve 111 is disposed around the crossbeam guide rail, the end of the connecting sleeve 111 is connected with the distance measuring sensor 300, and the two ends of the connecting sleeve 111 are connected through a fastener (e.g., a fastening bolt). When the position of the distance measuring sensor 300 needs to be changed, the fastener on the connecting sleeve 111 can be loosened firstly, so that the connecting sleeve 111 loosens the hooping effect on the beam guide rail, and after the distance measuring sensor 300 is moved, the fastener on the connecting sleeve 111 is locked again, so that the connecting sleeve 111 is locked on the beam guide rail, and the distance measuring sensor 300 is stably fixed.
The distance between the distance measuring sensor 300 and the wafer chuck 200 is not particularly limited in the embodiments of the present invention, for example, as an alternative embodiment of the present invention, the distance between the distance measuring sensor 300 and the wafer chuck 200 is about 200 mm.
In order to compare data intuitively, as a preferred embodiment of the present invention, the step S2 may specifically include:
step S21, obtaining a plurality of ranging values at a predetermined frequency through the ranging sensor 300 above the wafer chuck 200;
step S22, calculating difference values between the reference value and the plurality of distance measurement values respectively to obtain a plurality of height values; the reference value is the maximum distance measurement result of the distance measurement sensor 300 for measuring the distance of the carrying surface of the wafer chuck 200.
As shown in fig. 7, in the embodiment of the present invention, in order to visually represent the height of the wafer 10, the height value h is a difference between a distance D (reference value) between the ranging sensor 300 and the carrying surface of the wafer chuck 200 and a distance D between the ranging sensor 300 and the surface of the wafer 10. That is, after the ranging sensor 300 is mounted, the ranging sensor is zero-calibrated with the upper surface of the wafer chuck 200, and the height value h is the height of the wafer 10 from the bearing surface of the chuck with the upper surface of the chuck as the reference, so that the intuitiveness of observing the height of the surface of the wafer is improved.
It should be noted that, due to the assembly error, when the wafer chuck rotates, the distance between the predetermined position on the carrying surface and the distance measuring sensor 300 fluctuates up and down, so in the embodiment of the present invention, the maximum distance between the distance measuring sensor 300 and the carrying surface is used as the reference value D representing the distance between the distance measuring sensor 300 and the carrying surface, thereby ensuring that the height value h is always a positive value.
For example, as an optional implementation manner of the present invention, the wafer inspection module may determine whether the wafer 10 is in an abnormal fixed state according to the range of the height value (i.e. the difference between the maximum value Max and the minimum value Min), specifically:
step S3 may specifically include:
step S31, selecting a Maximum value Max (abbreviation of Maximum) and a Minimum value Min (abbreviation of Minimum) from the plurality of height values, calculating a range between two extreme values (i.e., the Maximum value Max and the Minimum value Min), and determining that the wafer 10 is in an abnormal fixed state if the range is greater than a first preset threshold.
It should be noted that the size of the first preset threshold may be selected according to hardware assembly accuracy in the semiconductor process chamber, that is, the first preset threshold may be determined according to mounting accuracy of structures such as the wafer chuck 200 in the semiconductor process chamber, and the like, and the amount of height fluctuation of the wafer surface finally caused by the first preset threshold is obtained. As an alternative embodiment of the present invention, the first preset threshold may be 0.2mm to 0.5 mm.
For example, the first preset threshold may be 0.3mm, that is, when the difference between the maximum value Max of the height values and the minimum value Min of the height values is greater than 0.3mm, it is determined that the tilt angle of the wafer 10 is too large, that is, the wafer 10 is not flatly placed and fixed, and the wafer 10 is in an abnormal fixed state; when the difference between the maximum value Max of the height values and the minimum value Min of the height values is not greater than 0.3mm, it is considered that the height fluctuation range at the predetermined position on the surface of the wafer 10 is within the error allowable range, and the wafer 10 is in a normal fixed state.
In the research, the inventor also found that in the prior art, the overall height of the wafer 10 may be too high or too low when being fixed, and although the wafer 10 is level enough, it is not fixed at a proper height with the clamping jaw 210, so that the risk of chipping also exists. For example, as shown in fig. 10, when the semiconductor processing chamber is applied to a wafer cleaning apparatus, the wafer chuck 200 further sprays a purge gas toward the bottom of the wafer 10 during the cleaning process to prevent the cleaning liquid from contacting the material deposited on the front surface of the wafer 10, in which case a gap between the wafer 10 and the carrying surface of the wafer chuck 200 is required to be large enough. That is, the height value h cannot be too small to affect the normal cleaning process.
As shown in fig. 8, 11 and 12, the clamping jaw 210 includes a plurality of (for example, 6 in the case shown) rotating shafts 211, the wafer chuck 200 has a plurality of clamping jaw holes distributed circumferentially around the wafer 10 placing area, and the plurality of rotating shafts 211 are disposed in the plurality of clamping jaw holes in a one-to-one correspondence and can be rotated simultaneously by a driving mechanism below the carrying surface. The top surface of the rotating shaft 211 is provided with an eccentric column 212 eccentric to the rotating shaft 211 (i.e. the eccentric column 212 is not coaxial with the rotating shaft 211), the driving mechanism drives the rotating shafts 211 to synchronously rotate, as shown in fig. 12, the plurality of eccentric columns 212 simultaneously approach the wafer 10 to contact the wafer 10, and the wafer can be clamped, so as to fix the position of the wafer; as shown in fig. 11, the wafer is released by simultaneously moving the eccentric columns 212 away from the wafer 10. In order to facilitate the vertical placement of the wafer 10 or the vertical removal of the wafer 10 between the eccentric columns 212, the top ends of the eccentric columns 212 have no inwardly protruding limiting structure, so that if the wafer 10 is positioned too high and is too close to the top ends of the eccentric columns 212, the wafer may be at risk of falling off upwards. Namely, the height h cannot be too large, so as to prevent the wafer from falling off and causing fragments.
In order to solve the above-mentioned technical problems and further improve the safety of the semiconductor process, as a preferred embodiment of the present invention, the wafer inspection module is further configured to determine that the wafer 10 is in an abnormal fixed state when the average Avg (abbreviation) of the height value h is not within an appropriate range.
Specifically, step S3 may further include:
step S32, an average value of the plurality of height values is calculated, and if the average value exceeds a preset fluctuation range, it is determined that the wafer 10 is in an abnormal fixed state.
For example, optionally, the preset fluctuation range is: greater than 0.3mm and less than 0.6 mm. That is, when the average value of the height values h of the wafer 10 is less than or equal to 0.3mm or greater than or equal to 0.6mm, the overall height of the wafer 10 is considered to be too high or too low and is not fixed at a proper height with the clamping jaw 210, and it is determined that the fixing state of the wafer 10 is abnormal, so as to avoid affecting the wafer cleaning process and eliminate the risk of fragments, and further improve the safety of the semiconductor process.
In order to further improve the safety of the semiconductor process, as a preferred embodiment of the present invention, the wafer inspection module is further configured to determine that the wafer 10 is in an abnormal fixed state when the variance Var (abbreviation) of the height value is too large.
Specifically, step S3 may further include:
step S33, calculating the variance of the height values, and if the variance is greater than or equal to a second preset threshold, determining that the wafer 10 is in an abnormal fixed state (step S33 and step S32 are both performed after step S31, and step S33 and step S32 may not be consecutive).
It should be noted that the ranging sensor 300 periodically emits light to the surface of the wafer 10 for ranging, and each time the wafer 10 rotates for a predetermined period, the ranging sensor 300 correspondingly obtains a plurality of height values, and the variance Var of the height values refers to the variance Var of the height values.
For example, alternatively, the wafer chuck 200 is slowly rotated at a rotation speed of 1 rpm (which is lower than that when the wafer chuck 200 normally performs a process), and the ranging sensor 300 detects the edge one turn at a frequency of 0.1 sec/time while the wafer chuck 200 is rotated, to obtain 10 height values.
As an alternative embodiment of the present invention, the second preset threshold may be 0.01mm2To 0.05mm2. Further optionally 0.03mm2. That is, when the variance Var of 10 height values is 0.03mm or more2And in the process, the clamping abnormality of the wafer is judged, so that the circumferential uniformity of the height of the surface of the wafer is further verified, and the safety of the semiconductor process is further improved.
In order to notify the operator of the abnormal holding state of the wafer 10 for processing in time, as a preferred embodiment of the present invention, the method further includes: and after the abnormal fixing state of the wafer 10 is judged, a throwing alarm is given.
The structure of the wafer inspection module according to the embodiments of the present invention is not particularly limited, and for example, the wafer inspection module may include a PLC (Programmable Logic Controller) circuit. The wafer detection assembly calculates data such as the maximum value Max, the minimum value Min, the average value Avg, the variance Var and the like of the height value through a PLC circuit.
For example, when the semiconductor process chamber is applied to a (single wafer) wafer cleaning apparatus, as shown in fig. 5, a pot 400 and a liquid medicine pipeline 500 may be further disposed in the chamber 100, wherein the pot 400 is used for recycling a cleaning liquid medicine on the wafer chuck 200, and the liquid medicine pipeline 500 is used for spraying the cleaning liquid medicine to the wafer chuck 200 and the wafer 10 carried thereon.
When a cleaning process is not performed, the liquid medicine pipeline 500 rotates to a position avoiding the mechanical arm, the mechanical arm enters the cavity 100 and performs a wafer conveying operation, after a wafer is conveyed, the plurality of clamping jaws 210 clamp the edge of the wafer 10, then the wafer fixing state is detected by the wafer detection assembly, if the wafer fixing state is normal, the wafer chuck 200 sinks into the pot body 400, and the liquid medicine pipeline 500 rotates and sprays cleaning liquid medicine to clean the wafer 10 in the pot body.
As a second aspect of the present invention, a semiconductor process chamber is provided, which includes a chamber body 100 and a wafer chuck 200 disposed in the chamber body 100, wherein the wafer chuck 200 is configured to fix a wafer 10 received from the outside of the process chamber through a carrying surface and drive the wafer 10 to rotate around an axis of the wafer chuck 200, and the process chamber further includes a wafer detecting component configured to detect a fixing state of the wafer 10 on the wafer chuck 200 according to the wafer placement state detecting method provided in the embodiment of the present invention.
In the semiconductor process chamber provided by the invention, the wafer detection assembly can detect the height of a preset position deviating from the axis of the wafer chuck 200 on the surface of the wafer 10, so that the abnormal fixing state of the wafer 10 can be found in time, the wafer 10 is prevented from falling off to cause fragments in the high-speed rotation process, the safety of the semiconductor process is improved, and the service life of semiconductor process equipment is prolonged.
In order to adjust the distance measuring points for wafers with different sizes, as a preferred embodiment of the present invention, as shown in fig. 5, the wafer detecting assembly includes a distance measuring sensor 300 and a sensor holder, the sensor holder includes a beam guide, two ends of the beam guide are respectively fixed on two side inner walls of the chamber 100, the beam guide passes over the wafer chuck 200, and the distance measuring sensor 300 is disposed on the beam guide and can move along the beam guide.
In order to switch the distance measuring sensor 300 and the crossbeam guide rail between the fixed state and the unfixed state, as a preferred embodiment of the invention, as shown in fig. 5, the wafer detecting assembly further includes a connecting sleeve, the connecting sleeve is disposed around the crossbeam guide rail, an end of the connecting sleeve is connected to the distance measuring sensor 300, and two ends of the connecting sleeve are connected by a fastener.
In order to notify the operator to process the wafer 10 in case of abnormal holding state, as a preferred embodiment of the present invention, as shown in fig. 9, the wafer inspection module is further configured to alarm the wafer 10 after determining that the holding state is abnormal.
The embodiment of the present invention does not specifically limit how the wafer detecting assembly is thrown out, for example, optionally, the semiconductor processing equipment further includes at least one of a buzzer, an indicator light, and a display screen. When the distance measuring sensor 300 determines that the wafer 10 is in an abnormal fixed state, a control signal is sent to corresponding hardware, so that the buzzer sends out an alarm ring, or the indicator lamp flickers/lights, or a corresponding alarm information prompt window pops up in a display picture of the display screen, and the like.
To facilitate understanding of the technical staff, the following provides a specific embodiment for detecting the wafer state in the semiconductor process chamber provided by the embodiment of the present invention by using the wafer placement state detection method provided by the embodiment of the present invention:
first, the jaws 210 on the wafer chuck 200 are controlled to open and a wafer to be cleaned is placed on the wafer chuck 200 by a robot outside the chamber. The wafer chuck 200 is controlled to spray purge gas to the wafer loaded on the loading surface thereof to empty the wafer, and then the clamping jaws 210 are controlled to close, thereby fixing the wafer.
Step S1 is executed, the wafer chuck 200 is controlled to drive the wafer 10 to rotate at a low speed at a preset rotation speed of 1 rpm, and at the same time, step S2 is executed, the distance measuring sensor 300 above the wafer chuck 200 is controlled to obtain 10 distance measuring values D at a preset frequency of 0.1 sec/time, and the difference between the reference value D and the distance measuring values D is calculated respectively to obtain 10 height values h.
And finally, analyzing the circumferential variation condition of the height values h, namely calculating the range between the maximum value Max and the minimum value Min of the 10 height values h, the average value Avg of the 10 height values h and the variance Var of the 10 height values h, and judging whether the range (Max-Min) is greater than a first preset threshold value of 0.3mm and the average value Avg is within a preset fluctuation range: greater than 0.3mm and less than 0.6mm, and whether the variance Var is less than a second preset threshold of 0.03mm2And (6) carrying out verification. Only when the range difference (Max-Min) is not more than 0.3mm of the first preset threshold, the average value Avg is within the preset fluctuation range and the variance Var is less than 0.03mm of the second preset threshold2And if one condition does not meet the requirement, judging that the state of the wafer is abnormal, and stopping the next action of the machine and giving an alarm.
It will be understood that the above embodiments are merely exemplary embodiments taken to illustrate the principles of the present invention, which is not limited thereto. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit and substance of the invention, and these modifications and improvements are also considered to be within the scope of the invention.

Claims (12)

1. A wafer placement state detection method is used for detecting the fixing state of a wafer on a wafer chuck, and is characterized by comprising the following steps:
controlling the wafer chuck to drive the wafer to rotate at a preset rotating speed;
acquiring a height value along the axial direction at a preset position on the surface of the wafer, wherein the preset distance is away from the axis of the wafer chuck;
and judging whether the fixed state of the wafer is abnormal or not according to the change situation of the height value.
2. The method as claimed in claim 1, wherein the obtaining of the height value of the wafer in the axial direction at a predetermined position from the axis of the wafer chuck on the surface of the wafer comprises:
acquiring a plurality of ranging values at a preset frequency through a ranging sensor above the wafer chuck;
calculating difference values between a reference value and the plurality of distance measurement values respectively to obtain a plurality of height values; the reference value is the maximum distance measurement result of the distance measurement sensor for measuring the distance of the bearing surface of the wafer chuck.
3. The method as claimed in claim 2, wherein the determining whether the wafer is in an abnormal fixed state according to the variation of the height value comprises:
and selecting the maximum value and the minimum value in the plurality of height values, calculating the range difference between the two extreme values, and judging that the wafer is abnormal in the fixed state if the range difference is greater than a first preset threshold value.
4. The method as claimed in claim 3, wherein the first predetermined threshold is 0.2mm to 0.5 mm.
5. The method as claimed in claim 2, wherein the determining whether the wafer is in an abnormal fixed state according to the variation of the height value comprises:
and calculating the average value of the plurality of height values, and if the average value exceeds a preset fluctuation range, judging that the wafer is abnormal in the fixed state.
6. The wafer placement state detection method according to claim 2, wherein the preset fluctuation range is: greater than 0.3mm and less than 0.6 mm.
7. The method as claimed in claim 2, wherein the determining whether the wafer is in an abnormal fixed state according to the variation of the height value comprises:
and calculating the variance of the plurality of height values, and if the variance is larger than or equal to a second preset threshold value, judging that the wafer is abnormal in the fixed state.
8. The method as claimed in claim 7, wherein the second predetermined threshold is 0.01mm to 0.05 mm.
9. The method as claimed in any one of claims 1 to 8, wherein the predetermined position is within a projection range of the wafer on the carrying surface, and the predetermined position is 2mm to 3mm away from an edge of the wafer.
10. A semiconductor process chamber comprising a cavity and a wafer chuck disposed in the cavity for holding a wafer received from outside the process chamber through a carrying surface and rotating the wafer about an axis of the wafer chuck, wherein the process chamber further comprises a wafer detection assembly for detecting a holding state of the wafer on the wafer chuck according to the wafer placement state detection method of any one of claims 1 to 9.
11. The semiconductor processing chamber of claim 10, wherein the wafer detection assembly comprises a distance measurement sensor and a sensor holder, the sensor holder comprises a beam guide, two ends of the beam guide are respectively fixed on two side inner walls of the cavity, the beam guide passes through the wafer chuck, and the distance measurement sensor is disposed on the beam guide and can move along the beam guide.
12. The semiconductor processing chamber of claim 11, wherein the wafer inspection assembly further comprises a connection sleeve disposed around the beam guide, wherein an end of the connection sleeve is connected to the distance measuring sensor, and wherein two ends of the connection sleeve are connected by a fastener.
CN202111158669.XA 2021-09-30 2021-09-30 Wafer placement state detection method and semiconductor process chamber Pending CN113921413A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114577178A (en) * 2022-03-17 2022-06-03 新阳硅密（上海）半导体技术有限公司 Electroplating head horizontal detection device and method
CN114769026A (en) * 2022-04-11 2022-07-22 深圳市聚强晶体有限公司 Special tool for spraying chip crystal oscillator

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114577178A (en) * 2022-03-17 2022-06-03 新阳硅密（上海）半导体技术有限公司 Electroplating head horizontal detection device and method
CN114577178B (en) * 2022-03-17 2023-11-24 新阳硅密（上海）半导体技术有限公司 Electroplating head level detection device and method
CN114769026A (en) * 2022-04-11 2022-07-22 深圳市聚强晶体有限公司 Special tool for spraying chip crystal oscillator

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