Elastic pin, wafer stress detection device and wafer stress detection method

Abstract

The invention provides an elastic pin, a wafer stress detection device and a wafer stress detection method.The elastic pin comprises a movable part, a fixed part, a reset part and a detection part, the movable part abuts against a wafer, the fixed part is movably connected with the movable part, the reset part is connected with the movable part and the fixed part, and the detection part is connected with the reset part. When the elastic pin is applied to wafer stress detection, the force for recovering to the initial state is applied to the movable part, the detection part detects the moving distance of the movable part, and the elastic arrangement can counteract part of supporting force, so that when the elastic pin is applied to wafer stress detection, the influence of the supporting force can be reduced, and the accuracy of stress detection can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor equipment, and in particular to an elastic pin, a wafer stress detection device and a wafer stress detection method. Background Art

[0002] In the semiconductor manufacturing process, a stress measurement machine is needed to measure the residual stress inside the wafer. The residual stress inside the wafer can be deduced by measuring the change in wafer warpage caused by film deposition before and after.

[0003] The existing technology is to use a probe to scan the local slope of several points evenly distributed on a diameter to obtain the surface morphology of the wafer in the diameter direction. The stress is calculated by the change in the bending radius of the wafer before and after the film deposition. When measuring the change in the wafer warpage caused by the film deposition, three hard pins are usually used for support, and then the measuring machine scans above the wafer. The wafer can also be suspended vertically for scanning.

[0004] When the wafer is supported by three hard pins or suspended vertically, the wafer will be deformed by the influence of gravity and the support force of the hard pins. The deformation measured by the measuring machine is not only the deformation caused by stress, but the result of the combined effect of stress, gravity and the support force of the hard pins. It cannot reflect the most real situation and has a large error. In addition, the probe needs to scan several points along the diameter of the wafer, which takes a long time to measure and is inefficient.

[0005] Therefore, it is necessary to provide a novel elastic pin, a wafer stress detection device and a wafer stress detection method to solve the above problems existing in the prior art. Summary of the invention

[0006] The object of the present invention is to provide an elastic pin, a wafer stress detection device and a wafer stress detection method, so as to reduce the influence of supporting force and improve the accuracy of stress detection.

[0007] To achieve the above object, the elastic pin of the present invention comprises:

[0008] A movable portion, used for abutting against the wafer;

[0009] A fixed part, movably connected to the movable part;

[0010] a restoring portion, connected to the movable portion and the fixed portion, and configured to apply a force to the movable portion to restore the movable portion to an initial state; and

[0011] The detection part is used to detect the moving distance of the movable part.

[0012] The beneficial effects of the elastic pin are: the movable part abuts against the wafer, the fixed part is movably connected to the movable part, the reset part is connected to the movable part and the fixed part, a force is applied to the movable part to restore it to an initial state, the detection part detects the moving distance of the movable part, and the elastic setting can offset part of the supporting force. Therefore, when the elastic pin is applied to wafer stress detection, the influence of the supporting force can be reduced and the accuracy of stress detection can be improved.

[0013] Optionally, the movable part includes a first head and a first body, the first head is arranged on the first body, and the first head is in an arc shape, used to abut against the wafer, a first cavity is arranged in the fixed part, a first opening is opened on the fixed part, the first opening is connected to the first cavity, the first body is arranged in the first cavity, and extends from the first opening to the outside of the fixed part.

[0014] Optionally, the resetting portion is disposed in the first cavity.

[0015] Optionally, a first blocking portion is provided at a portion of the first body located in the first cavity, and a second blocking portion is provided at the first opening, and the first blocking portion and the second blocking portion block each other to prevent the first body from escaping from the first cavity.

[0016] Optionally, the detection unit includes a first transmitting unit, a first receiving unit and a first reflecting unit, the first transmitting unit and the first receiving unit are arranged on the first body, the first reflecting unit is arranged in the first cavity, the first transmitting unit is used to transmit the detection signal, the first reflecting unit is used to reflect the detection signal, and the first receiving unit is used to receive the reflected detection signal.

[0017] Optionally, the detection unit includes a first transmitting unit, a first receiving unit and a first reflecting unit, the first transmitting unit and the first receiving unit are arranged in the first cavity, the first reflecting unit is arranged on the first body, the first transmitting unit is used to transmit a detection signal, the first reflecting unit is used to reflect the detection signal, and the first receiving unit is used to receive the reflected detection signal.

[0018] Optionally, the detection unit includes a plurality of second transmitting units and a plurality of second receiving units, wherein the plurality of second transmitting units are sequentially arranged on the inner wall of the first cavity along the movement direction of the first body, and the plurality of second receiving units are sequentially arranged on the inner wall of the first cavity along the movement direction of the first body, and the second transmitting units correspond one-to-one to the second receiving units.

[0019] Optionally, the movable part includes a second head and a second body, the second head is arranged on the second body, and the second head is in an arc shape, used to abut the wafer, a second cavity is provided in the second body, a second opening is opened on the second body, and the second cavity and the second opening are connected, the fixed part is partially located in the second cavity, and part of the fixed part extends to the outside of the second cavity through the second opening.

[0020] Optionally, a third cavity is opened in the fixing part, a third opening is opened on the part of the fixing part located in the second cavity, and the third cavity and the third opening are connected, and the resetting part is arranged in the third cavity and extends outside the third cavity through the third opening.

[0021] Optionally, the resetting portion is arranged at a portion of the fixing portion extending to outside the second cavity through the second opening.

[0022] Optionally, a third blocking portion is provided on the second opening, and a fourth blocking portion is provided on a portion of the fixing portion located in the second cavity, and the third blocking portion and the fourth blocking portion block each other to prevent the fixing portion from being separated from the second cavity.

[0023] Optionally, the detection unit includes a third transmitting unit, a third receiving unit and a reflecting unit, the third transmitting unit and the third receiving unit are arranged on the second cavity, the reflecting unit is arranged on the fixed unit, the third transmitting unit is used to transmit the detection signal, the reflecting unit is used to reflect the detection signal, and the third receiving unit is used to receive the reflected detection signal.

[0024] Optionally, the detection unit includes a third transmitting unit, a third receiving unit and a reflecting unit, the third transmitting unit and the third receiving unit are arranged on the fixed unit, the reflecting unit is arranged on the second cavity, the third transmitting unit is used to transmit the detection signal, the reflecting unit is used to reflect the detection signal, and the third receiving unit is used to receive the reflected detection signal.

[0025] Optionally, the detection unit includes a plurality of fourth transmitting units and a plurality of fourth receiving units, wherein the plurality of fourth transmitting units are sequentially arranged on the inner wall of the second cavity along the movement direction of the second body, and the plurality of fourth receiving units are sequentially arranged on the inner wall of the second cavity along the movement direction of the second body, and the fourth transmitting units correspond one-to-one to the fourth receiving units.

[0026] The present invention also provides a wafer stress detection device, comprising a plurality of elastic pins and a base, wherein the elastic pins are arranged on the base and distributed in an array, and the elastic pins include a movable part, a fixed part, a reset part and a detection part, wherein the movable part is used to abut against the wafer, the fixed part is movably connected to the movable part, the reset part is connected to the movable part and the fixed part, and is used to apply a force to the movable part to restore it to an initial state, and the detection part is used to detect the moving distance of the movable part.

[0027] The beneficial effect of the wafer stress detection device is that the application of the elastic pins can offset part of the supporting force, thereby improving the accuracy of stress detection.

[0028] Optionally, a plurality of openings are formed on the base, and the openings are distributed at equal intervals along the central axis of the base.

[0029] Optionally, the wafer stress detection device further includes hard pins corresponding one-to-one to the openings, and the hard pins pass through the openings for taking and placing wafers.

[0030] The present invention also provides a wafer stress detection method, comprising:

[0031] A wafer stress detection device is provided, the wafer stress detection device comprising an elastic pin and a base, the elastic pin being arranged on the base and distributed in an array, the elastic pin comprising a movable part, a fixed part, a reset part and a detection part, the movable part being used to abut against a wafer, the fixed part being movably connected to the movable part, the reset part being connected to the movable part and the fixed part and being used to apply a force to the movable part to restore it to an initial state, and the detection part being used to detect a moving distance of the movable part;

[0032] Placing a wafer on the wafer stress detection device, the movable parts of the plurality of elastic pins move downward under the pressure of the wafer, and the detection part detects the moving distance of the movable parts to obtain the descending height of the movable parts of the plurality of elastic pins;

[0033] Calculating the radius of the arc according to the descending height of the movable portion of the plurality of elastic pins;

[0034] The internal stress of the wafer is calculated according to the radius of the arc and the internal stress calculation formula. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A top view of a wafer stress detection device in some embodiments of the present invention;

[0036] Figure 2 A schematic diagram of a first state of placing a wafer in some embodiments of the present invention;

[0037] Figure 3 A schematic diagram of a second state of placing a wafer in some embodiments of the present invention;

[0038] Figure 4 A schematic diagram of a third state of placing a wafer in some embodiments of the present invention;

[0039] Figure 5 A front view of an elastic pin in some embodiments of the present invention;

[0040] Figure 6 In the first embodiment of the present invention Figure 5 a cross-sectional view of the elastic pin shown;

[0041] Figure 7 In the second embodiment of the present invention Figure 5 a cross-sectional view of the elastic pin shown;

[0042] Figure 8 In the third embodiment of the present invention Figure 5 a cross-sectional view of the elastic pin shown;

[0043] Fig. 9 In the fourth embodiment of the present invention Figure 5 a cross-sectional view of the elastic pin shown;

[0044] Fig.10 In some embodiments of the present invention Fig. 9 The cross-sectional view along line a-a';

[0045] Fig.11 A front view of elastic pins in some other embodiments of the present invention;

[0046] Fig.12 In the first embodiment of the present invention Fig.11 a cross-sectional view of the elastic pin shown;

[0047] Fig.13 In the second embodiment of the present invention Fig.11 a cross-sectional view of the elastic pin shown;

[0048] Fig.14 In the third embodiment of the present invention Fig.11 a cross-sectional view of the elastic pin shown;

[0049] Fig.15 It is a front view of elastic pins in other embodiments of the present invention;

[0050] Fig.16 In the first embodiment of the present invention Fig.15 a cross-sectional view of the elastic pin shown;

[0051] Fig.17 In the second embodiment of the present invention Fig.15 a cross-sectional view of the elastic pin shown;

[0052] Fig.18 In the third embodiment of the present invention Fig.15 a cross-sectional view of the elastic pin shown;

[0053] Fig.19 In the fourth embodiment of the present invention Fig.15 a cross-sectional view of the elastic pin shown;

[0054] Fig. 20 In some embodiments of the present invention Fig.19 Cross-sectional view along line b-b'.

[0055] Description of reference numerals:

[0056] 100, wafer stress detection device; 101, elastic pin; 102, base; 103, wafer; 104, second head; 105, second body; 106, third blocking part; 107, fourth blocking part; 108, support seat; 109, inner extension; 200, hard pin; 1011, first head; 1012, first body; 1013, fixing part; 1014, spring; 1015, first transmitting part; 1016, first receiving part; 1017, first reflecting part; 1 018, second transmitting part; 1019, second receiving part; 1020, third transmitting part; 1021, third receiving part; 1022, third reflecting part; 1023, fourth transmitting part; 1024, fourth receiving part; 1030, detecting part; 1031, opening; 1051, second cavity; 1052, second opening; 1053, third opening; 2021, third receiving part; 10121, first blocking part; 10131, first cavity; 10132, second blocking part. DETAILED DESCRIPTION

[0057] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be understood by people with general skills in the field to which the present invention belongs. "Including" and similar words used in this article mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0058] In view of the problems existing in the prior art, an embodiment of the present invention provides a wafer stress detection device. Figure 1 The wafer stress detection device 100 includes a plurality of elastic pins 101 and a base 102 . The elastic pins 101 are disposed on the base 102 and distributed in an array.

[0059] In some embodiments, the base is provided with a plurality of openings, and the openings are evenly spaced along the central axis of the base; the wafer stress detection device further includes hard pins corresponding one-to-one to the openings, and the hard pins pass through the openings for taking and placing wafers.

[0060] Reference Figure 1 The base 102 is circular and has three openings 1031 formed thereon. The three openings 1031 are evenly spaced along the central axis of the base 102 .

[0061] Figure 2 A schematic diagram of a first state of placing a wafer in some embodiments of the present invention; Figure 3 A schematic diagram of a second state of placing a wafer in some embodiments of the present invention; Figure 4 103 is a schematic diagram of a third state of placing a wafer in some embodiments of the present invention. The three hard pins 200 pass through the openings 1031 to support the wafer 103. Figure 2 As shown; the three hard pins 200 slowly descend until the wafer 103 is fully supported by the elastic pins 101, as shown Figure 3 As shown; the three hard pins 200 further descend until they are out of contact with the wafer 103, as shown Figure 4 shown.

[0062] In some embodiments, the elastic pin includes a movable portion, a fixed portion, a reset portion, and a detection portion. The movable portion is used to abut against the wafer; the fixed portion is movably connected to the movable portion; the reset portion is connected to the movable portion and the fixed portion, and is used to apply a force to restore the movable portion to an initial state; and the detection portion is provided on at least one of the movable portion and the fixed portion, and is used to detect the moving distance of the movable portion.

[0063] In some embodiments, the movable part includes a first head and a first body, the first head is arranged on the first body, and the first head is in an arc shape, which is used to abut the wafer, a first cavity is arranged in the fixed part, a first opening is opened on the fixed part, the first opening is connected with the first cavity, the first body is arranged in the first cavity, and extends from the first opening to the outside of the fixed part, the reset part is arranged in the first cavity, a first blocking part is provided at the part of the first body located in the first cavity, and a second blocking part is provided at the first opening, and the first blocking part and the second blocking part block each other to prevent the first body from leaving the first cavity.

[0064] Figure 5 A front view of an elastic pin in some embodiments of the present invention; Figure 6 In the first embodiment of the present invention Figure 5 Cross-section of the elastic pin shown. Figure 5 and Figure 6 The first head 1011 is hemispherical, the first body 1012 is cylindrical, the circular surface of the first head 1011 and the upper surface of the first body 1012 are the same size, the circular surface of the first head 1011 and the upper surface of the first body 1012 are connected, wherein the first head 1011 and the first body 1012 are integrally formed or fixedly connected.

[0065] Reference Figure 5 and Figure 6 The fixing portion 1013 is cylindrical, and a first cylindrical cavity 10131 is provided in the fixing portion 1013. A first circular opening is provided on the upper surface of the fixing portion 1013, and the diameter of the first opening is larger than the diameter of the first main body 1012. The first main body 1012 is arranged in the first cavity 10131, extending from the first opening to the outside of the first cavity 10131, and the first main body 1012 can slide in the first cavity 10131.

[0066] Reference Figure 5 and Figure 6, the reset part is a spring 1014, the detection part 1030 is a displacement recorder, the detection part 1030 is fixedly arranged at the bottom of the first body 1012, the spring 1014 is arranged in the first cavity 10131, one end of the spring 1014 is fixedly connected or abutted with the detection part 1030, and the other end of the spring 1014 is fixedly connected or abutted with the bottom surface of the first cavity 10131. Since the elastic force of the spring 1014 is proportional to the compression amount, the detection part 1030 can calculate the compression amount of the spring 1014 by detecting the elastic force of the spring 1014, and the compression amount of the spring 1014 is the descending height of the first body 1012.

[0067] Reference Figure 5 and Figure 6 A first blocking portion 10121 is provided at the bottom of the first main body 1012, and the first blocking portion 10121 is ring-shaped. A second blocking portion 10132 is provided at the first opening, and the second blocking portion 10132 is ring-shaped. The outer diameter of the first blocking portion 10121 is greater than the inner diameter of the second blocking portion 10132. When the first head 1011 is not in contact with the wafer, the spring 1014 pushes the first main body 1012 upward, and the second blocking portion 10132 contacts the first blocking portion 10121 and blocks the first blocking portion 10121, thereby preventing the first main body 1012 from completely separating from the first cavity 10131.

[0068] Figure 7 In the second embodiment of the present invention Figure 5 Cross-section of the elastic pin shown. Figure 7 and Figure 6 The difference is that: the detection unit includes a first emitting unit 1015, a first receiving unit 1016 and a first reflecting unit 1017, the first emitting unit 1015 and the first receiving unit 1016 are arranged on the lower surface of the first body 1012, the first reflecting unit 1017 is arranged on the inner bottom surface of the first cavity 10131, the first emitting unit 1015 is used to emit a detection signal α, the first reflecting unit 1017 is used to reflect the detection signal α, and the first receiving unit 1016 is used to receive the detection signal α reflected by the first reflecting unit 1017.

[0069] Figure 8 In the third embodiment of the present invention Figure 5 Cross-section of the elastic pin shown. Figure 8 and Figure 7 The difference is that the first transmitting part 1015 and the first receiving part 1016 are arranged on the inner bottom surface of the first cavity 10131, and the first reflecting part 1017 is arranged on the lower surface of the first body 1012.

[0070] In some embodiments, the first emitting part is a laser light source, the first receiving part is a laser receiver, and the first reflecting part is a reflector. The propagation speed of the laser is a fixed v1, and the time from the laser light source emitting the laser to the laser receiver receiving the laser is t1, then the propagation distance of the laser can be calculated as L1=v1×t1, then the distance from the laser light source to the light mirror can be calculated as H1=L1 / 2, when the first head 1011 is not in contact with the wafer, the distance from the laser light source to the light mirror is a fixed H2, then the descending height of the first body is H2-H1.

[0071] In some other embodiments, the first transmitting part is an ultrasonic generator, the first receiving part is an ultrasonic receiver, and the first reflecting part is an ultrasonic reflecting device. The propagation speed of ultrasonic waves is a fixed v2, and the time from the ultrasonic generator emitting ultrasonic waves to the ultrasonic receiver receiving ultrasonic waves is t2, then the propagation distance of ultrasonic waves can be calculated as L2=v2×t2, then the distance from the ultrasonic generator to the ultrasonic reflecting device can be calculated as H1=L2 / 2, and when the first head 1011 is not in contact with the wafer, the distance from the ultrasonic generator to the ultrasonic reflecting device is a fixed H2, and the descending height of the first body is H2-H1.

[0072] Fig. 9 In the fourth embodiment of the present invention Figure 5 Cross-section of the elastic pin shown. Figure 8 and Figure 6 The difference is that: the detection unit includes a plurality of second emitting units 1018 and a plurality of second receiving units 1019, and the plurality of second emitting units 1018 are sequentially arranged on the inner wall of the first cavity 10131 along the movement direction of the first body 1012, and the plurality of second receiving units 1019 are sequentially arranged on the inner wall of the first cavity 10131 along the movement direction of the first body 1012, and the second emitting units 1018 correspond to the second receiving units 1019 one by one.

[0073] Fig.10 In some embodiments of the present invention Fig. 9 The cross-sectional view of a-a' in FIG. Fig.10 The connection line between the second transmitting unit 1018 and the corresponding second receiving unit 1019 does not pass through the spring 1014, so as to prevent the spring 1014 from hindering the signal detection between the second transmitting unit 1018 and the second receiving unit 1019.

[0074] Reference Fig. 9When the first head 1011 abuts against the wafer and descends, the first body 1012 will block between part of the second emitting part 1018 and the second receiving part 1019, thereby blocking the signal transmission between part of the second emitting part 1018 and the second receiving part 1019. The distance between adjacent second emitting parts 1018 is known. By counting the number of second emitting parts 1018 whose signal transmission is blocked, the descending height of the first body 1012 can be obtained. The second emitting part 1018 is a laser light source or an ultrasonic generator, and the second receiving part 1019 is a laser receiver or an ultrasonic receiver. Taking 10 second emitting parts 1018 and 10 second receiving parts 1019 as an example, the distance between adjacent second emitting parts 1018 is h. When the first head 1011 abuts against the wafer and descends, the first body 1012 is blocked between 5 second emitting parts 1018 and the second receiving part 1019, which means that the descending height of the first body 1012 can be obtained as 5h.

[0075] In some embodiments, the movable part includes a second head and a second body, the second head is arranged on the second body, and the second head is in an arc shape for abutting against the wafer, a second cavity is provided in the second body, a second opening is opened on the second body, and the second cavity and the second opening are connected, the fixed part is partially located in the second cavity, and part of the fixed part extends to the outside of the second cavity through the second opening, a third blocking part is provided on the second opening, and a fourth blocking part is provided on the part of the fixed part located in the second cavity, the third blocking part and the fourth blocking part block each other to prevent the fixed part from detaching from the second cavity, and the reset part is provided on the part of the fixed part extending to the outside of the second cavity through the second opening.

[0076] Fig.11 A front view of elastic pins in some other embodiments of the present invention; Fig.12 In the first embodiment of the present invention Fig.11 Cross-section of the elastic pin shown. Fig.11 and Fig.12 The second head 104 is hemispherical, the second body 105 is cylindrical, the circular surface of the second head 104 and the upper surface of the second body 105 are the same size, the circular surface of the second head 104 and the upper surface of the second body 105 are connected, a second cavity 1051 is provided in the second body 105, and a second opening 1052 is provided on the lower bottom surface of the second body 105, the second cavity 1051 and the second opening 1052 are connected, wherein the second head 104 and the second body 105 are integrally formed or fixedly connected.

[0077] Reference Fig.11 and Fig.12 The fixing portion includes a support seat 108 and an inner extension portion 109, the inner extension portion 109 is cylindrical, the inner extension portion 109 is disposed in the second cavity 1051, and extends from the second opening 1052 to the outside of the second cavity 1051 and is connected to the support seat 108, and the inner extension portion 109 can slide along the second cavity 1051.

[0078] Reference Fig.11 and Fig.12 The reset portion is a spring 1014 , which surrounds the inner extension portion 109 , one end of the spring 1014 is connected to or abuts the support seat 108 , and the other end of the spring 1014 is connected to or abuts the bottom surface of the second body 105 .

[0079] Reference Fig.11 and Fig.12 A third blocking portion 106 is provided on the second opening 1052, and the third blocking portion 106 is annular. A fourth blocking portion 107 is provided around the upper surface of the inner extension portion 109, and the fourth blocking portion 107 is annular. The outer diameter of the fourth blocking portion 107 is greater than the inner diameter of the third blocking portion 106. When the second head portion 104 is not in contact with the wafer, the spring 1014 pushes the second body 105 upward, and the fourth blocking portion 107 contacts and blocks the third blocking portion 106, thereby preventing the inner extension portion 109 from leaving the second cavity 1051.

[0080] Reference Fig.12 The detection unit includes a third emitting unit 1020, a third receiving unit 1021 and a third reflecting unit 1022. The third emitting unit 1020 and the third receiving unit 1021 are arranged on the upper surface of the second cavity 1051, and the third reflecting unit 1022 is arranged on the upper surface of the inner extension 109. The third emitting unit 1020 is used to emit a detection signal, the third reflecting unit 1022 is used to reflect the detection signal, and the third receiving unit 1021 is used to receive the reflected detection signal.

[0081] Fig.13 In the second embodiment of the present invention Fig.11 Cross-section of the elastic pin shown. Fig.13 and Fig.12 The difference is that the third transmitting portion 1020 and the third receiving portion 2021 are arranged on the upper surface of the inner extension portion 109 , and the third reflecting portion 1022 is arranged on the upper surface of the second cavity 1051 .

[0082] Fig.14 In the third embodiment of the present invention Fig.11 Cross-section of the elastic pin shown. Fig.14 and Fig.12 The difference is that: the detection unit includes a plurality of fourth transmitting units 1023 and a plurality of fourth receiving units 1024, and the plurality of fourth transmitting units 1023 are sequentially arranged on the inner wall of the second cavity 1051 along the movement direction of the second body 105, and the plurality of fourth receiving units 1024 are sequentially arranged on the inner wall of the second cavity 1051 along the movement direction of the second body 105, and the fourth transmitting units 1023 correspond to the fourth receiving units 1024 one by one.

[0083] In some embodiments, the movable part includes a second head and a second body, the second head is arranged on the second body, and the second head is in an arc shape for abutting against the wafer, a second cavity is arranged in the second body, a second opening is opened on the second body, and the second cavity and the second opening are communicated, the fixed part is partially located in the second cavity, and the part of the fixed part extends to the outside of the second cavity through the second opening, a third blocking part is provided on the second opening, and a fourth blocking part is provided on the part of the fixed part located in the second cavity, the third blocking part and the fourth blocking part block each other to prevent the fixed part from detaching from the second cavity, a third cavity is opened in the fixed part, a third opening is opened on the part of the fixed part located in the second cavity, and the third cavity and the third opening are communicated, and the reset part is arranged in the third cavity and extends to the outside of the third cavity through the third opening.

[0084] Fig.15 It is a front view of elastic pins in other embodiments of the present invention; Fig.16 In the first embodiment of the present invention Fig.15 Cross-section of the elastic pin shown. Fig.16 and Fig.12 The difference is that: a third cavity 101321 is opened in the inner extension part 109, a third opening 1053 is opened on the upper surface of the inner extension part 109, and the third opening 1053 is connected with the third cavity 101321, the detection part 1030 is a displacement recorder, and the detection part 1030 is fixedly arranged on the upper surface of the second cavity 1051, and the reset part is a spring 1014, and the spring 1014 is arranged in the third cavity 101321, one end of the spring 1014 is connected to or abutted with the detection part 1030, and the other end of the spring 1014 is connected to or abutted with the lower bottom surface of the third cavity 101321.

[0085] Fig.17 In the second embodiment of the present invention Fig.15 Cross-section of the elastic pin shown. Fig.17and Fig.16 The difference is that: the detection unit includes a third transmitting unit 1020, a third receiving unit 1021 and a third reflecting unit 1022, the third transmitting unit 1020 and the third receiving unit 1021 are arranged on the upper surface of the second cavity 1051, the third reflecting unit 1022 is arranged on the lower bottom surface of the third cavity 101321, the third transmitting unit 1020 is used to transmit the detection signal, the third reflecting unit 1022 is used to reflect the detection signal, and the third receiving unit 1021 is used to receive the reflected detection signal.

[0086] Fig.18 In the third embodiment of the present invention Fig.15 Cross-section of the elastic pin shown. Fig.18 and Fig.17 The difference is that the third reflecting part 1022 is arranged on the upper surface of the second cavity 1051, and the third emitting part 1020 and the third receiving part 1021 are arranged on the lower bottom surface of the third cavity 101321.

[0087] In some embodiments, the detection principle of the third transmitting unit, the third receiving unit and the third reflecting unit is the same as the detection principle of the first transmitting unit, the first receiving unit and the first reflecting unit, and is not described in detail here.

[0088] Fig.19 In the fourth embodiment of the present invention Fig.15 Cross-section of the elastic pin shown. Fig.19 and Fig.16 The difference is that: the detection unit includes a plurality of fourth transmitting units 1023 and a plurality of fourth receiving units 1024, and the plurality of fourth transmitting units 1023 are sequentially arranged on the inner wall of the second cavity 1051 along the movement direction of the second body 105, and the plurality of fourth receiving units 1024 are sequentially arranged on the inner wall of the second cavity 1051 along the movement direction of the second body 105, and the fourth transmitting units 1023 correspond to the fourth receiving units 1024 one by one.

[0089] Fig. 20 In some embodiments of the present invention Fig.19 The cross-sectional view of b-b' in Fig. Fig. 20 , the connection line between the fourth transmitting unit 1023 and the corresponding fourth receiving unit 1024 does not pass through the spring 1014, so as to prevent the spring 1014 from hindering the signal detection between the fourth transmitting unit 1023 and the fourth receiving unit 1024.

[0090] In some embodiments, the detection principle of the fourth transmitting unit and the fourth receiving unit is the same as the detection principle of the second transmitting unit and the second receiving unit, and will not be described in detail herein.

[0091] The present invention also provides a wafer stress detection method, comprising:

[0092] A wafer stress detection device is provided, the wafer stress detection device comprising an elastic pin and a base, the elastic pin being arranged on the base and distributed in an array, the elastic pin comprising a movable part, a fixed part, a reset part and a detection part, the movable part being used to abut against a wafer, the fixed part being movably connected to the movable part, the reset part being connected to the movable part and the fixed part and being used to apply a force to the movable part to restore it to an initial state, and the detection part being used to detect a moving distance of the movable part;

[0093] Placing a wafer on the wafer stress detection device, the movable parts of the plurality of elastic pins move downward under the pressure of the wafer, and the detection part detects the moving distance of the movable parts to obtain the descending height of the movable parts of the plurality of elastic pins;

[0094] Calculating the radius of the arc according to the descending height of the movable portion of the plurality of elastic pins;

[0095] The internal stress of the wafer is calculated according to the radius of the arc and the internal stress calculation formula.

[0096] In some embodiments, after placing the wafer on the wafer stress detection device, the active portion of each elastic pin will move under the action of the wafer pressure, and the detection unit can detect the displacement distance of the active portion of each elastic pin, that is, the descending height of the first body or the descending height of the second body, and then the radius of the wafer arc can be calculated. The radius of the wafer arc before film deposition is expressed as R pre , the radius of the wafer arc after film deposition is expressed as R post , then the radius change of the wafer arc before and after film deposition is R, The internal stress calculation formula Then the internal stress ρ can be calculated, Es represents the elastic modulus of the base material, v represents the Poisson's ratio of the base material, t s represents the substrate thickness, t f Indicates film thickness.

[0097] In some embodiments, the radius of the wafer arc before thin film deposition is calculated in the same technical manner as the radius of the wafer arc after thin film deposition. The elastic pin with the largest drop height of the first body is used as the reference point, and the drop heights of several elastic pins located on the same straight line and passing through the reference point are used for calculation. Since the highest height of the lower surface of the first body is known, the current height of the lower surface of the first body can be calculated by the drop height. A fitting plane is selected, and the height of the fitting plane is subtracted from the current height below the first body to obtain several fitting heights. Several fitting heights are fitted to obtain an expression of the wafer arc, that is, the arc of the wafer. Two points on the wafer arc are selected as perpendicular lines of the tangent. The intersection of the perpendicular lines of the two tangents is the center of the wafer arc, and the vertical distance from the center to the tangent is the radius of the arc.

[0098] Although the embodiments of the present invention are described in detail above, it is obvious to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations are within the scope and spirit of the present invention as described in the claims. Moreover, the present invention described herein may have other embodiments and may be implemented or realized in a variety of ways.

Claims

1. An elastic pin, characterized in that: include: A movable portion, used for abutting against the wafer; A fixed part, movably connected to the movable part; a restoring portion, connected to the movable portion and the fixed portion, and used to apply a force to the movable portion to restore it to an initial state; as well as The detection part is used to detect the moving distance of the movable part.

2. The elastic pin according to claim 1, characterized in that: The movable part includes a first head and a first main body, the first head is arranged on the first main body, and the first head is in an arc shape, used to abut against the wafer, a first cavity is arranged in the fixed part, a first opening is opened on the fixed part, the first opening is connected with the first cavity, the first main body is arranged in the first cavity, and extends from the first opening to the outside of the fixed part.

3. The elastic pin according to claim 2, characterized in that: The resetting portion is disposed in the first cavity.

4. The elastic pin according to claim 2, characterized in that: A first blocking portion is disposed at a portion of the first body located in the first cavity, and a second blocking portion is disposed at the first opening. The first blocking portion and the second blocking portion block each other to prevent the first body from being separated from the first cavity.

5. The elastic pin according to any one of claims 2 to 4, characterized in that: The reset part is a spring, and the detection part is a displacement recorder. The displacement recorder is fixedly arranged at the bottom of the first main body, and the spring is arranged in the first cavity. One end of the spring is fixedly connected or abutted with the displacement recorder, and the other end of the spring is fixedly connected or abutted with the bottom surface of the first cavity; the displacement recorder can calculate the compression amount of the spring by detecting the elastic force of the spring, and the compression amount of the spring is the descending height of the first main body.

6. The elastic pin according to any one of claims 2 to 4, characterized in that: The detection unit includes a first transmitting unit, a first receiving unit and a first reflecting unit, the first transmitting unit and the first receiving unit are arranged on the first body, the first reflecting unit is arranged in the first cavity, the first transmitting unit is used to transmit a detection signal, the first reflecting unit is used to reflect the detection signal, and the first receiving unit is used to receive the reflected detection signal.

7. The elastic pin according to any one of claims 2 to 4, characterized in that: The detection unit includes a first transmitting unit, a first receiving unit and a first reflecting unit, the first transmitting unit and the first receiving unit are arranged in the first cavity, the first reflecting unit is arranged on the first body, the first transmitting unit is used to transmit a detection signal, the first reflecting unit is used to reflect the detection signal, and the first receiving unit is used to receive the reflected detection signal.

8. The elastic pin according to any one of claims 2 to 4, characterized in that: The detection unit includes a plurality of second transmitting units and a plurality of second receiving units, wherein the plurality of second transmitting units are sequentially arranged on the inner wall of the first cavity along the movement direction of the first body, and the plurality of second receiving units are sequentially arranged on the inner wall of the first cavity along the movement direction of the first body, and the second transmitting units correspond one to one to the second receiving units.

9. The elastic pin according to claim 1, characterized in that: The movable part includes a second head and a second body, the second head is arranged on the second body, and the second head is in an arc shape, used to abut the wafer, a second cavity is arranged in the second body, a second opening is opened on the second body, and the second cavity and the second opening are connected, the fixed part is partially located in the second cavity, and part of the fixed part extends to the outside of the second cavity through the second opening.

10. The elastic pin according to claim 9, characterized in that: A third cavity is defined in the fixing portion, a third opening is defined on the portion of the fixing portion located in the second cavity, and the third cavity and the third opening are communicated with each other, and the resetting portion is disposed in the third cavity and extends to the outside of the third cavity through the third opening.

11. The elastic pin according to claim 9, characterized in that: The restoring portion is disposed at a portion of the fixing portion extending to outside the second cavity through the second opening.

12. The elastic pin according to claim 9, characterized in that: A third blocking portion is disposed on the second opening, and a fourth blocking portion is disposed on the portion of the fixing portion located in the second cavity. The third blocking portion and the fourth blocking portion block each other to prevent the fixing portion from being separated from the second cavity.

13. The elastic pin according to any one of claims 9 to 12, characterized in that: The detection part includes a third transmitting part, a third receiving part and a third reflecting part, the third transmitting part and the third receiving part are arranged on the second cavity, the third reflecting part is arranged on the fixing part, the third transmitting part is used to transmit the detection signal, the third reflecting part is used to reflect the detection signal, and the third receiving part is used to receive the reflected detection signal.

14. The elastic pin according to any one of claims 9 to 12, characterized in that: The detection part includes a third transmitting part, a third receiving part and a third reflecting part, the third transmitting part and the third receiving part are arranged on the fixing part, the third reflecting part is arranged on the second cavity, the third transmitting part is used to transmit the detection signal, the third reflecting part is used to reflect the detection signal, and the third receiving part is used to receive the reflected detection signal.

15. The elastic pin according to any one of claims 9 to 12, characterized in that: The detection unit includes a plurality of fourth transmitting units and a plurality of fourth receiving units, wherein the plurality of fourth transmitting units are sequentially arranged on the inner wall of the second cavity along the movement direction of the second body, and the plurality of fourth receiving units are sequentially arranged on the inner wall of the second cavity along the movement direction of the second body, and the fourth transmitting units correspond one to one with the fourth receiving units.

16. A wafer stress detection device, characterized in that: It comprises the elastic pins and a base as described in any one of claims 1 to 15, wherein the elastic pins are arranged on the base and distributed in an array.

17. The wafer stress detection device according to claim 16, characterized in that: The base is provided with a plurality of openings, and the openings are distributed at equal intervals along the central axis of the base.

18. The wafer stress detection device according to claim 17, characterized in that: It also includes hard pins corresponding to the openings one by one, and the hard pins pass through the openings for taking and placing wafers.

19. A wafer stress detection method, characterized in that: include: Using the wafer stress detection device according to any one of claims 16 to 18; Placing a wafer on the wafer stress detection device, the movable parts of the plurality of elastic pins move downward under the pressure of the wafer, and the detection part detects the moving distance of the movable parts to obtain the descending height of the movable parts of the plurality of elastic pins; Calculating the radius of the arc according to the descending height of the movable portion of the plurality of elastic pins; The internal stress of the wafer is calculated according to the radius of the arc and the internal stress calculation formula.

Images