CN117604605A - Single crystal growth equipment and silicon melt liquid level position control method thereof - Google Patents
Single crystal growth equipment and silicon melt liquid level position control method thereof Download PDFInfo
- Publication number
- CN117604605A CN117604605A CN202311624696.0A CN202311624696A CN117604605A CN 117604605 A CN117604605 A CN 117604605A CN 202311624696 A CN202311624696 A CN 202311624696A CN 117604605 A CN117604605 A CN 117604605A
- Authority
- CN
- China
- Prior art keywords
- position information
- current
- crucible
- quartz
- obtaining
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 title claims abstract description 86
- 229910052710 silicon Inorganic materials 0.000 title claims abstract description 86
- 239000010703 silicon Substances 0.000 title claims abstract description 86
- 239000013078 crystal Substances 0.000 title claims abstract description 75
- 239000007788 liquid Substances 0.000 title claims abstract description 64
- 238000000034 method Methods 0.000 title claims abstract description 55
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 57
- 238000001816 cooling Methods 0.000 claims abstract description 24
- 239000010453 quartz Substances 0.000 claims description 88
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 88
- 229910002651 NO3 Inorganic materials 0.000 claims description 66
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 claims description 66
- 230000002159 abnormal effect Effects 0.000 claims description 57
- 125000000449 nitro group Chemical group [O-][N+](*)=O 0.000 claims description 4
- 239000000155 melt Substances 0.000 description 11
- 229910021421 monocrystalline silicon Inorganic materials 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 5
- 230000005856 abnormality Effects 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 230000007547 defect Effects 0.000 description 1
- 230000009643 growth defect Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 150000002828 nitro derivatives Chemical class 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 238000004781 supercooling Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B11/00—Single-crystal growth by normal freezing or freezing under temperature gradient, e.g. Bridgman-Stockbarger method
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B11/00—Single-crystal growth by normal freezing or freezing under temperature gradient, e.g. Bridgman-Stockbarger method
- C30B11/006—Controlling or regulating
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
- C30B29/02—Elements
- C30B29/06—Silicon
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Crystallography & Structural Chemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
Abstract
The present disclosure provides a single crystal growth apparatus and a silicon melt level position control method thereof, the apparatus including a single crystal furnace and a processing unit, the single crystal furnace including: the device comprises a crucible, a guide cylinder and a water cooling jacket, wherein Dan Yingxiao is arranged at the lower part of the guide cylinder, and a calibration mark is arranged at the lower part of the water cooling jacket; the first image acquisition unit is used for acquiring image information of the reflection of the measuring end; the second image acquisition unit is used for acquiring image information of the calibration marks; the processing unit includes: a first processing module for obtaining first position information P based on image information of the reflection A The method comprises the steps of carrying out a first treatment on the surface of the A second processing module for obtaining second position information P based on the image information of the calibration mark B The method comprises the steps of carrying out a first treatment on the surface of the A third processing module for based on the first position information P A And second position information P B And obtaining control parameters for characterizing and controlling the lifting position of the crucible. The single crystal growth equipment and the silicon melt liquid level position control method thereof can be used for controlling the silicon melt liquid level position of the single crystalThe liquid level position of the silicon melt is controlled to improve the productivity and the product quality.
Description
Technical Field
The invention relates to the technical field of semiconductor manufacturing, in particular to single crystal growth equipment and a silicon melt liquid level position control method thereof.
Background
In the production of single crystal silicon, stable production of single crystal silicon of a desired quality is important for preventing production loss and improving the yield of products. In particular, in recent years, with the progress of high integration and miniaturization of semiconductor devices, it has become an issue to stably produce low-defect single crystal silicon by reducing Grown-in defects in single crystal silicon.
It is known that the growth defect is determined by the temperature gradient of the crystal at the growth interface and the growth rate of single crystal silicon, and thus it is necessary to control the temperature gradient of the crystal at the growth interface with high accuracy. In order to control the temperature gradient of the crystal at the growth interface, a cylindrical heat shielding member for shielding radiant heat is usually provided so as to surround the silicon single crystal grown above the melt surface. Thereby increasing the crystal temperature gradient under high temperature conditions and obtaining defect-free crystals at high speed.
In the single crystal silicon manufacturing apparatus provided with the heat shielding member, in order to accurately control the temperature gradient of the crystal at the growth interface, it is necessary to control the interval between the melt surface and the lower end of the heat shielding member (i.e., the silicon melt surface gap, which may be referred to as melt gap) to a predetermined interval with high accuracy.
As the silicon single crystal grows, the silicon melt contained in the crucible decreases and the melt level continues to decrease. Therefore, conventionally, the melt level position is controlled by the following method: the amount of lowering of the melt level position is predicted according to the growth rate of the silicon single crystal, and a raising command is issued to the crucible holding shaft according to the predicted value, so that the crucible position is raised to prevent the lowering of the melt level position, and the melt level position is held at a predetermined position constantly. However, as the diameter of the crystal increases, the diameter of the crucible increases, and the position of the melt surface greatly changes due to variations in the thickness of the crucible wall, deformation and expansion of the crucible occurring during operation. Therefore, it is difficult to control the position of the melt surface with high accuracy and to maintain the melt surface at a predetermined position by controlling the crucible position to rise only based on the predicted value.
Based on the above, in the related art, a single CCD (Charge coupled Device) camera is often used to track the position of the silicon melt level, so as to control the silicon melt level gap (melt gap), but the following problems exist: the method comprises the steps of confirming and calibrating the position of the molten liquid level in the initial stage of crystal 10 growth, wherein in the process from shouldering to shouldering and constant diameter, the technological level difference of field personnel causes the shouldering to be too large or too small, so that the molten liquid level is lowered or raised, or Dan Yingxiao is lowered or the position is deviated due to shaking, so that a CCD camera cannot normally capture the reflection of quartz nitrate, thus the lifting of a real crucible is abnormal, the position of the liquid level of silicon melt is changed, the gap between the liquid level of the silicon melt is abnormal, and the product quality is unstable; in addition, after the abnormal position of the liquid level of the silicon melt is usually adjusted and calibrated according to experience, the adjustment level is limited by the experience value of a mediator, and therefore the abnormal risk of the product is further increased.
Disclosure of Invention
The embodiment of the disclosure provides single crystal growth equipment and a silicon melt liquid level position control method thereof, which can accurately control the position of the silicon melt liquid level in the single crystal growth equipment so as to improve the productivity and the product quality.
The technical scheme provided by the embodiment of the disclosure is as follows:
according to a first aspect of the present disclosure, there is provided a single crystal growth apparatus comprising:
a single crystal furnace, comprising: a crucible for holding a silicon melt; the measuring device comprises a guide cylinder and a water cooling jacket, wherein the guide cylinder and the water cooling jacket are arranged above the crucible, dan Yingxiao is arranged at the lower part of the guide cylinder, the measuring end of quartz nitrate is downwards arranged along the vertical direction, and a calibration mark is arranged at the lower part of the water cooling jacket; the first image acquisition unit is used for acquiring image information of reflection of the measuring end of the quartz nitrate on the liquid level of the silicon melt; the second image acquisition unit is used for acquiring the image information of the calibration marks; and
A processing unit comprising:
a first processing module for obtaining first position information P representing the liquid level position of the silicon melt based on the image information of the reflection A ；
A second processing module for obtaining second position information P representing the liquid level position of the silicon melt based on the image information of the calibration mark B ；
A third processing module configured to, based on the first position information P A And the second position information P B And obtaining control parameters for characterizing and controlling the lifting position of the crucible.
Illustratively, the third processing module is configured to specifically:
based on the first initial calibration position information P A0 And second initial calibration position information P B0 Obtaining the compensation parameter delta P C0 Wherein the first initial calibration position information P A0 For the first position information when the distance between the silicon solution level and the measuring end of the quartz nitrate is the target gap value, the second initial calibration position information P B0 The second position information is the second position information when the distance between the liquid level of the silicon solution and the measuring end of the quartz nitrate is a target gap value;
will present the first position information P A1 And the first initial calibration position information P A0 Comparing to judge whether the current position of the quartz nitrate or the crucible is abnormal;
if so, based on the compensation parameter DeltaP C0 Current first position information P A1 And second initial calibration position information P B0 Calculating the actual offset DeltaP of the quartz nitro or the crucible A The method comprises the following steps: deltaP A ＝P B0+ △P C0- P A1 And based on the actual offset DeltaP A For the current first position information P A1 Compensating to obtain the control parameters; or based on the current second position information P B1 Obtaining the control parameters;
if not, based on the current first position information P A1 And obtaining the control parameters.
Illustratively, the third processing module is configured to specifically further:
when the current first position information P A1 And the first initial calibration position information P A0 When the deviation of the quartz is larger than or equal to a first threshold value, judging that the quartz nitrate or the crucible is abnormal currently and based on the current firstTwo-position information P B1 Obtaining the control parameters;
when the current first position information P A1 And the first initial calibration position information P A0 When the deviation of the above is larger than the second threshold value and smaller than the first threshold value, judging that the position of the quartz nitrate or the crucible is abnormal, and based on the actual deviation DeltaP A For the current first position information P A1 Compensating to obtain the control parameters;
when the current first position information P A1 And the first initial calibration position information P A0 When the deviation of the position of the quartz nitrate and the crucible is smaller than a first threshold value, judging that the positions of the quartz nitrate and the crucible are not abnormal, and based on the current first position information P A1 And obtaining the control parameters.
Illustratively, the third processing module is configured to specifically further:
will present second position information P B1 With the first initial calibration position information P B0 Comparing to judge whether the current position of the water cooling jacket is abnormal;
if yes, calculating the actual offset delta P of the water cooling jacket B The method comprises the following steps: deltaP B ＝P A0 -△P C0- P B1 And based on the actual offset DeltaP B For the current second position information P B1 And compensating.
Illustratively, the third processing module is configured to specifically further:
when the current first position information P A1 And the first initial calibration position information P A0 And (3) when the deviation of the water cooling sleeve is larger than or equal to a third threshold value, judging whether the current position of the water cooling sleeve is abnormal or not.
Illustratively, the water jacket is configured to include at least two sections of sub-jackets that are nested within each other such that the jackets are vertically telescoping; the processing unit is further configured to control the water jacket to axially expand and contract to compensate the position of the crucible when the crucible is at an upper limit or a lower limit of its lifting stroke and the current position of the crucible does not reach a target position characterized by the control parameter.
According to a second aspect of the present disclosure, there is provided a silicon melt level control method in a single crystal growth apparatus, which is applied to the single crystal growth apparatus as described above, the method comprising:
collecting image information of a reflection image of the quartz nitrate measuring end on the liquid level of the silicon melt, and obtaining first position information P representing the liquid level position of the silicon melt based on the image information of the reflection image A ；
Acquiring the image information of the calibration mark, and obtaining second position information P representing the liquid level position of the silicon melt based on the image information of the calibration mark B ；
Based on the first position information P A And the second position information P B Obtaining control parameters for characterizing and controlling the lifting position of the crucible;
and controlling the crucible to lift based on the control parameter so as to control the position of the liquid level of the silicon solution.
Exemplary, the method is based on the first position information P A And the second position information P B Obtaining control parameters for characterizing and controlling the lifting position of the crucible, wherein the control parameters specifically comprise:
based on the first initial calibration position information P A0 And second initial calibration position information P B0 Obtaining the compensation parameter delta P C0 Wherein the first initial calibration position information P A0 For the first position information when the distance between the silicon solution level and the measuring end of the quartz nitrate is the target gap value, the second initial calibration position information P B0 The second position information is the second position information when the distance between the liquid level of the silicon solution and the measuring end of the quartz nitrate is a target gap value;
will present the first position information P A1 And the first initial calibration position information P A0 Comparing to judge whether the current position of the quartz nitrate or the crucible is abnormal;
if yes, calculating the quartz nitrate or the quartz nitrateActual offset ΔP of the crucible A The method comprises the following steps: deltaP A ＝P B0+ △P C0- P A1 And based on the actual offset DeltaP A For the current first position information P A1 Compensating to obtain the control parameters; or based on the current second position information P B1 Obtaining the control parameters;
if not, based on the current first position information P A1 And obtaining the control parameters.
The actual offset DeltaP of the quartz crystal or the crucible is calculated by the method A The method comprises the following steps: deltaP A ＝P B0+ △P C0- P A1 And based on the actual offset DeltaP A For the current first position information P A1 Compensating to obtain the control parameters; or based on the current second position information P B1 Obtaining the control parameters; if not, based on the current first position information P A1 Obtaining the control parameters; the method specifically comprises the following steps:
when the current first position information P A1 And the first initial calibration position information P A0 When the deviation of the current quartz nitrate or the crucible is larger than or equal to a first threshold value, judging that the quartz nitrate or the crucible is abnormal and based on the current second position information P B1 Obtaining the control parameters;
when the current first position information P A1 And the first initial calibration position information P A0 When the deviation of the above is larger than the second threshold value and smaller than the first threshold value, judging that the position of the quartz nitrate or the crucible is abnormal, and based on the actual deviation DeltaP A For the current first position information P A1 Compensating to obtain the control parameters;
when the current first position information P A1 And the first initial calibration position information P A0 When the deviation of the position of the quartz nitrate and the crucible is smaller than a first threshold value, judging that the positions of the quartz nitrate and the crucible are not abnormal, and based on the current first position information P A1 And obtaining the control parameters.
Exemplary, the first location basedInformation P A And the second position information P B Obtaining control parameters for characterizing and controlling the lifting position of the crucible; in particular, the utility model also comprises the following components,
will present second position information P B1 With the first initial calibration position information PB 0 Comparing to judge whether the current position of the water cooling jacket is abnormal;
if yes, calculating the actual offset delta P of the water cooling jacket B The method comprises the following steps: deltaP B ＝P A0 -△P C0- P B1 And based on the actual offset DeltaP B For the current second position information P B1 And compensating.
Illustratively, the method further comprises: and when the crucible is at the upper limit or the lower limit of the lifting stroke and the current position of the crucible does not reach the target position represented by the control parameter, controlling the water cooling jacket to axially stretch so as to compensate the position of the crucible.
The beneficial effects brought by the embodiment of the disclosure are as follows:
in the single crystal growth apparatus and the melt level control method thereof provided in the embodiments of the present disclosure, a first image acquisition unit may be used to acquire a reflection image of quartz nitrate, a calibration mark may be further provided at a lower portion of a water jacket, and a second image acquisition unit may be provided to acquire the image of the calibration mark, so that not only the first image acquisition unit may be used to acquire the reflection image of quartz nitrate to measure the position of the liquid level of the silicon solution, but also the image of the calibration mark may be used to measure the position of the liquid level of the silicon solution, so that when the crystal is in each stage of the growth process, the position of the liquid level of the silicon solution changes due to too large or too small shoulder due to the difference of operations of operators, or, in case of abnormal position of quartz nitrate due to shaking, dropping or position offset, etc., the position of the quartz nitrate may be calibrated by the image of the calibration mark, so as to improve the accuracy of the measurement of the position of the liquid level of the silicon solution, so that the position of the silicon solution remains stable, and productivity and product quality are improved.
Drawings
FIG. 1 is a schematic view showing the structure of a single crystal growth apparatus according to an embodiment of the present disclosure;
fig. 2 shows a flowchart of a silicon melt level control method in a single crystal growth apparatus provided by an embodiment of the present disclosure.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present disclosure more apparent, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present disclosure. It will be apparent that the described embodiments are some, but not all, of the embodiments of the present disclosure. All other embodiments, which can be made by one of ordinary skill in the art without the need for inventive faculty, are within the scope of the present disclosure, based on the described embodiments of the present disclosure.
Unless defined otherwise, technical or scientific terms used in this disclosure should be given the ordinary meaning as understood by one of ordinary skill in the art to which this disclosure belongs. The terms "first," "second," and the like, as used in this disclosure, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. Likewise, the terms "a," "an," or "the" and similar terms do not denote a limitation of quantity, but rather denote the presence of at least one. The word "comprising" or "comprises", and the like, means that elements or items preceding the word are included in the element or item listed after the word and equivalents thereof, but does not exclude other elements or items. The terms "connected" or "connected," and the like, are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", etc. are used merely to indicate relative positional relationships, which may also be changed when the absolute position of the object to be described is changed.
In the related art, a single CCD (Charge coupled Device) camera is used to track the position of the silicon melt level, and control of the silicon melt level gap (melt gap) is achieved, but there are the following problems: the method comprises the steps of confirming and calibrating the position of the molten liquid level in the initial stage of crystal 10 growth, wherein in the process from shouldering to shouldering and constant diameter, the technological level difference of field personnel causes the shouldering to be too large or too small, so that the molten liquid level is lowered or raised, or Dan Yingxiao is lowered or the position is deviated due to shaking, so that a CCD camera cannot normally capture the reflection of quartz nitrate, thus the lifting of a real crucible is abnormal, the position of the liquid level of silicon melt is changed, the gap between the liquid level of the silicon melt is abnormal, and the product quality is unstable; in addition, after the abnormal position of the liquid level of the silicon melt, adjustment and calibration are usually performed empirically, and the adjustment level is limited by the experience value of a mediator, thereby further causing the risk of abnormal products.
In order to solve the above-described problems, an embodiment of the present disclosure provides a single crystal growth apparatus including a single crystal furnace and a processing unit.
As shown in fig. 1, the single crystal furnace includes a furnace body 100, a crucible 200, a guide cylinder 300, a water jacket 400, a first image acquisition unit 500, a second image acquisition unit 600, and the like.
The crucible 200 is arranged in the furnace body 100, the crucible 200 is used for containing silicon melt S, the guide cylinder 300 and the water cooling jacket 400 are both arranged above the crucible 200, the lower part of the guide cylinder 300 is provided with quartz nitrate 310, the bottom end of the Dan Yingxiao is a measuring end, and the measuring end is downwards arranged along the vertical direction;
the lower portion of the water jacket 400 is provided with a calibration mark 410, and the calibration mark 410 may be any suitable mark pattern or mark that can be recognized by the second image acquisition unit 600;
the quartz nitrate 310 is located in the field of view of the first image acquisition unit 500, the first image acquisition unit 500 is configured to acquire image information of a reflection image of a measurement end of the quartz nitrate on the liquid surface of the silicon melt S, and the first image acquisition unit 500 may be any suitable image acquisition element such as a CCD camera;
the calibration mark 410 is located in the field of view of the second image capturing unit 600, the second image capturing unit 600 is configured to capture image information of the calibration mark 410, and any suitable image capturing element such as a CCD camera may be selected as the second image capturing unit 600.
The processing unit (not illustrated in the figures) may comprise: the first processing module is used for obtaining first position information P representing the liquid level position of the silicon melt S based on the image information of the reflection image A The method comprises the steps of carrying out a first treatment on the surface of the The second processing module is configured to obtain second position information P representing a position of the liquid surface of the silicon melt S based on the image information of the calibration mark 410 B The method comprises the steps of carrying out a first treatment on the surface of the The third processing module is used for based on the first position information P A And the second position information P B A control parameter characterizing the elevation of the crucible 200 is obtained.
In the single crystal growth apparatus provided by the embodiments of the present disclosure, the first image acquisition unit 500 may be used to acquire a reflection image of the quartz nitrate, a calibration mark 410 is further disposed at the lower portion of the water jacket 400, and the second image acquisition unit 600 may be disposed to acquire an image of the calibration mark 410, so that not only the first image acquisition unit 500 may be used to acquire a reflection image of the quartz nitrate to measure the liquid level position of the silicon solution, but also the image of the calibration mark 410 may be acquired to measure the liquid level position of the silicon solution. Thus, when the crystal 10 is in each stage of the growth process, the shoulder is too large or too small due to the operation difference of the operator, so that the position of the liquid level of the silicon melt S is changed, or if the quartz nitrate is abnormal due to shaking, dropping or position deviation, etc., the calibration crucible can be lifted through the image of the calibration mark 410, so as to improve the accuracy of measuring the position of the silicon solution surface, keep the position of the liquid level of the silicon melt S stable, and improve the productivity and the product quality.
Specifically, in some exemplary embodiments, the third processing module is configured to specifically:
based on the first initial calibration position information P A0 And second initial calibration position information P B0 Obtaining the compensation parameter delta P C0 Wherein the first initial calibration position information P A0 For the first position information when the interval between the silicon solution level and the measuring end of the quartz crystal 310 is a target gap value,the second initial calibration position information P B0 Is the second position information when the interval between the silicon solution level and the measuring end of the quartz nitrate 310 is a target gap value;
will present the first position information P A1 And the first initial calibration position information P A0 Comparing to determine whether the current position of the quartz crystal 310 or the crucible 200 is abnormal;
if so, based on the compensation parameter DeltaP C0 Current first position information P A1 And second initial calibration position information P B0 Calculating the actual offset DeltaP of the quartz crystal or the crucible 200 A And based on the actual offset DeltaP A For the current first position information P A1 Compensating to obtain the control parameters; or based on the current second position information P B1 Obtaining the control parameters;
if not, based on the current first position information P A1 And obtaining the control parameters.
In the above scheme, the first initial calibration position information P A0 And the second initial calibration position information P B0 The acquisition procedure of (a) may be as follows:
in the process of growing the crystal 10, for example, in the early shoulder stage, firstly, image acquisition is performed on the inverted image of the measuring end of the quartz nitrate at the preset position, the crucible elevation is calibrated by combining the target clearance value based on the inverted image of the quartz nitrate acquired at the moment, so that the liquid level of the silicon melt S is positioned at the calibration position, and at the moment, the first position information obtained based on the inverted image of the quartz nitrate acquired when the liquid level of the silicon melt S is positioned at the calibration position is the first initial calibration position information P A0 And, when the silicon solution surface is at the calibration position, the second image acquisition unit 600 acquires the image of the lower calibration mark 410 of the water jacket 400, and the second position information obtained based on the image at this time is the second initial calibration position information P B0 。
Since the relative position between the calibration mark 410 and the quartz crystal 310 is theoretically several during the whole crystal 10 growth processIs kept unchanged based on the first initial calibration position information P A0 And the second initial calibration position information P B0 Obtaining the compensation parameter delta P C0 . Exemplary, the compensation parameter ΔP C0 Equal to P A0 And P B0 Is a difference in (c).
If the quartz nitrate is abnormal or the position of the crucible 200 is abnormal, dan Yingxiao reflection images acquired in the growth process of the crystal 10 are abnormal, and corresponding to the obtained current first position information P A1 Abnormality, e.g. current first position information P A1 And the first initial calibration position information P A0 Based on the comparison result, it is determined whether the current position of the quartz crystal 310 or the crucible 200 is abnormal.
In the case where the position of the quartz nitrate is abnormal or the position of the crucible 200 is abnormal as a result of the determination, for example, the quartz nitrate may still be within the field of view of the first image acquisition unit 500, and at this time, the compensation parameter Δp may be based on C0 Calculating an actual offset DeltaP of the quartz crystal 310 or the crucible 200 from the current first position information A . Exemplary, actual offset ΔP A The method comprises the following steps: deltaP A ＝P B0+ △P C0- P A1 . And based on the actual offset ΔP A For the current first position information P A1 And compensating to obtain the control parameters, and controlling the liquid level position of the silicon melt S.
When the determination result is that the position of the quartz nitrate is abnormal or the position of the crucible 200 is abnormal, for example, the quartz nitrate falls off and is not in the field of view of the first image acquisition unit 500, in this way, since the possibility that the position of the water jacket 400 is affected during the growth of the crystal 10 is small, the positions of the quartz nitrate and the crucible 200 are affected by a plurality of factors, if Dan Yingxiao and the position of the crucible 200 deviate, at this time, the control parameters can be obtained based on the image of the calibration mark 410 on the water jacket 400 alone, so as to perform the control of the liquid level position of the silicon melt S, so as to achieve the purpose of precisely controlling the liquid level position of the silicon melt S.
When the determination result shows that the positions of the quartz nitrate and the crucible 200 are not abnormal, the control parameter can be obtained based on the inverted image of the quartz nitrate alone to control the liquid level position of the silicon melt S.
Illustratively, the third processing module is configured to specifically further:
when the current first position information P A1 And the first initial calibration position information P A0 When the deviation of (2) is greater than or equal to a first threshold value, determining that the quartz crystal 310 or the crucible 200 is abnormal, and based on the current second position information P B1 Obtaining the control parameters;
when the current first position information P A1 And the first initial calibration position information P A0 When the deviation of (a) is larger than the second threshold value and smaller than the first threshold value, determining that the position of the quartz crystal 310 or the crucible 200 is abnormal, and based on the actual deviation DeltaP A For the current first position information P A1 Compensating to obtain the control parameters;
when the current first position information P A1 And the first initial calibration position information P A0 When the deviation of the (C) is smaller than the first threshold value, judging that the positions of the quartz nitrate and the crucible 200 are not abnormal, and based on the current first position information P A1 And obtaining the control parameters.
By adopting the scheme, the first threshold value and the second threshold value can be prestored in the processing unit and are according to the current first position information P A1 And the first initial calibration position information P A0 And the difference of the above is compared with the first threshold value and the second threshold value to judge whether the offset of the quartz crystal or the crucible 200 is too large to exceed the allowable error range.
It will be appreciated that in practice, it is possible to determine whether the locations of the quartz crystal 310 and the crucible 200 are abnormal in other ways.
Furthermore, in some exemplary embodiments of the present disclosure, the third processing module is configured to specifically further:
will currently be the firstTwo-position information P B1 With the first initial calibration position information P B0 Comparing to determine whether the current position of the water jacket 400 is abnormal;
if so, based on the compensation parameter DeltaP C0 Current second position information P B1 And first initial calibration position information P A0 Calculating the actual offset DeltaP of the water jacket 400 B Exemplary, ΔP B ＝P A0 -△P C0- P B1 And based on the actual offset DeltaP B For the current second position information P B1 And compensating.
With the above scheme, if the position of the water jacket 400 is shifted, the current second position information P can be obtained B1 Compensation is performed to precisely control the position of the liquid level of the silicon melt S.
It should be noted that, the calibration process of obtaining the first initial calibration position information and the second initial calibration position information may be completed in the initial stage of single crystal growth, the offset or the falling of the quartz nitrate may occur in the shoulder or shoulder turning (oversheller) stage, and the abnormal position of the crucible 200 may occur in the isodiametric stage of the crystal 10, and in practical application, the specific component and the specific position where the abnormality occurs may be determined when the reflection image acquired by the first image acquisition unit 500 is abnormal in combination with the stage where the actual growth process is located.
In some examples of the disclosure, the third processing module is configured to specifically further: when the current first position information P A1 And the first initial calibration position information P A0 When the deviation of the water jacket 400 is greater than or equal to a third threshold, determining whether the current position of the water jacket 400 is abnormal.
With the above-described arrangement, since the position of the water jacket 400 hardly changes during the growth of the crystal 10, it is possible to base the current first position information P A1 And the first initial calibration position information P A0 To determine whether the position of the water jacket 400 is abnormal, if so, based on the actual offset Δp of the water jacket 400 B To compensate for the second position information.
Furthermore, in some exemplary embodiments of the present disclosure, the water jacket 400 is configured to include at least two sections of the sub-water jacket 400, at least two sections of the sub-water jacket 400 being nested with each other such that the water jacket 400 is vertically retractable. Illustratively, each segment of the sub-water jacket 400 may be configured to have a main body in a ring shape, and the inner diameter of each sub-water jacket 400 is gradually reduced in the axial direction so as to be coupled to each other.
By designing the water jacket 400 to be axially telescopic, during the growth of the crystal 10, the telescopic length of the water jacket 400 can be optimized according to the horizontal capacity of process operators, the silicon single crystal growth quality data of the previous furnace and the abnormal control of the liquid level position of the silicon melt S, so as to further improve the axial temperature gradient of the crystal 10 during the growth and improve the product productivity and the product quality.
Specifically, the processing unit is further configured to control the water jacket 400 to axially expand and contract to compensate for the position of the crucible 200 when the crucible 200 is at an upper limit or a lower limit of its lifting travel and the current position of the crucible 200 does not reach the target position characterized by the control parameter.
Here, when the crucible 200 is lifted, the travel of the crucible may be limited by the structure of the lifting assembly, and when the crucible cannot be lifted further to reach a more ideal target position even if the crucible reaches the upper and lower limit positions, the axial temperature gradient of the crystal 10 during growth may be further improved by controlling the water jacket 400 to axially expand and contract so as to compensate the position of the crucible 200.
In other words, when the cooling of the crystal 10 does not reach the desired level due to the abnormality in the solid-liquid level position, the shortage of cooling power or supercooling due to the abnormality in the liquid level position of the silicon melt S can be compensated for by the adjustment of the position of the water jacket 400.
In addition, the embodiment of the disclosure also provides a silicon melt liquid level control method in the single crystal growth equipment, which is applied to the single crystal growth equipment provided by the embodiment of the disclosure. The method can also bring the beneficial effects brought by the single crystal growth equipment provided by the embodiment of the disclosure.
As shown in fig. 2, a method for controlling a liquid level of a silicon melt in a single crystal growth apparatus according to an embodiment of the present disclosure includes:
step S01, acquiring image information of a reflection image of the measuring end of the quartz nitrate on the liquid surface of the silicon melt S, and obtaining first position information P representing the liquid surface position of the silicon melt S based on the image information of the reflection image A The method comprises the steps of carrying out a first treatment on the surface of the Acquiring the image information of the calibration mark 410, and obtaining second position information P representing the liquid level position of the silicon melt S based on the image information of the calibration mark 410 B The method comprises the steps of carrying out a first treatment on the surface of the Based on the first position information P A And the second position information P B Obtaining control parameters for characterizing and controlling the lifting position of the crucible 200;
step S02, controlling the crucible 200 to lift based on the control parameters so as to control the position of the liquid level of the silicon solution.
Illustratively, the step S02 specifically includes:
step S021, based on the first initial calibration position information P A0 And the second initial calibration position information P B0 Obtaining the compensation parameter delta P C0 Wherein the first initial calibration position information P A0 The second initial calibration position information P is the first position information when the distance between the silicon solution level and the measuring end of the quartz crystal 310 is the target gap value B0 Is the second position information when the interval between the silicon solution level and the measuring end of the quartz nitrate 310 is a target gap value;
step S022, the current first position information P A1 And the first initial calibration position information P A0 Comparing to determine whether the current position of the quartz crystal 310 or the crucible 200 is abnormal;
step S021, if yes, calculating the actual offset DeltaP of the quartz nitro-compound or the crucible 200 A The method comprises the following steps: deltaP A ＝P B0+ △P C0- P A1 And based on the actual offset DeltaP A For the current first position information P A1 Compensating to obtainThe control parameters; or based on the current second position information P B1 Obtaining the control parameters; if not, based on the current first position information P A1 And obtaining the control parameters.
The step S021 specifically includes:
step S0211, when the current first position information P A1 And the first initial calibration position information P A0 When the deviation of (2) is greater than or equal to a first threshold value, determining that the quartz crystal 310 or the crucible 200 is abnormal, and based on the current second position information P B1 Obtaining the control parameters;
step S0212, when the current first position information P A1 And the first initial calibration position information P A0 When the deviation of (a) is larger than the second threshold value and smaller than the first threshold value, determining that the position of the quartz crystal 310 or the crucible 200 is abnormal, and based on the actual deviation DeltaP A For the current first position information P A1 Compensating to obtain the control parameters;
step S0213, when the current first position information P A1 And the first initial calibration position information P A0 When the deviation of the (C) is smaller than the first threshold value, judging that the positions of the quartz nitrate and the crucible 200 are not abnormal, and based on the current first position information P A1 And obtaining the control parameters.
The step S02 specifically includes, for example,
step S023, the current second position information P B1 With the first initial calibration position information PB 0 Comparing to determine whether the current position of the water jacket 400 is abnormal;
step S024, if yes, calculating the actual offset DeltaP of the water jacket 400 B The method comprises the following steps: deltaP B ＝P A0 -△P C0- P B1 And based on the actual offset DeltaP B For the current second position information P B1 And compensating.
Illustratively, the method further comprises:
and S03, controlling the water cooling jacket 400 to axially stretch and retract so as to compensate the position of the crucible 200 when the crucible 200 is at the upper limit or the lower limit of the lifting stroke and the current position of the crucible 200 does not reach the target position represented by the control parameter.
The following points need to be described:
(1) The drawings of the embodiments of the present disclosure relate only to the structures related to the embodiments of the present disclosure, and other structures may refer to the general design.
(2) In the drawings for describing embodiments of the present disclosure, the thickness of layers or regions is exaggerated or reduced for clarity, i.e., the drawings are not drawn to actual scale. It will be understood that when an element such as a layer, film, region or substrate is referred to as being "on" or "under" another element, it can be "directly on" or "under" the other element or intervening elements may be present.
(3) The embodiments of the present disclosure and features in the embodiments may be combined with each other to arrive at a new embodiment without conflict.
The above is merely a specific embodiment of the disclosure, but the protection scope of the disclosure should not be limited thereto, and the protection scope of the disclosure should be subject to the claims.
Claims (11)
1. A single crystal growing apparatus, comprising:
a single crystal furnace, comprising: a crucible for holding a silicon melt; the measuring device comprises a guide cylinder and a water cooling jacket, wherein the guide cylinder and the water cooling jacket are arranged above the crucible, dan Yingxiao is arranged at the lower part of the guide cylinder, the measuring end of quartz nitrate is downwards arranged along the vertical direction, and a calibration mark is arranged at the lower part of the water cooling jacket; the first image acquisition unit is used for acquiring image information of reflection of the measuring end of the quartz nitrate on the liquid level of the silicon melt; the second image acquisition unit is used for acquiring the image information of the calibration marks; and
A processing unit comprising:
a first processing module for obtaining first position information P representing the liquid level position of the silicon melt based on the image information of the reflection A ；
A second processing module for obtaining second position information P representing the liquid level position of the silicon melt based on the image information of the calibration mark B ；
A third processing module configured to, based on the first position information P A And the second position information P B And obtaining control parameters for characterizing and controlling the lifting position of the crucible.
2. The single crystal growth apparatus of claim 1, wherein the third processing module is configured to:
based on the first initial calibration position information P A0 And second initial calibration position information P B0 Obtaining the compensation parameter delta P C0 Wherein the first initial calibration position information P A0 The first position information and the second initial calibration position information P are obtained when the distance between the liquid level of the silicon solution and the measuring end of the quartz nitrate is the target gap value B0 The second position information is the second position information when the distance between the liquid level of the silicon solution and the measuring end of the quartz nitrate is a target gap value;
will present the first position information P A1 And the first initial calibration position information P A0 Comparing to judge whether the current position of the quartz nitrate or the crucible is abnormal;
if so, based on the compensation parameter DeltaP C0 Current first position information P A1 And second initial calibration position information P B0 Calculating the actual offset DeltaP of the quartz nitro or the crucible A And based on the actual offset DeltaP A For the current first position information P A1 Compensating to obtain the control parameters; or based on the current second position information P B1 Obtaining the control parameters;
if not, based on the current first position information P A1 And obtaining the control parameters.
3. The single crystal growth apparatus of claim 2, wherein the third processing module is configured to specifically further:
when the current first position information P A1 And the first initial calibration position information P A0 When the deviation of the current quartz nitrate or the crucible is larger than or equal to a first threshold value, judging that the quartz nitrate or the crucible is abnormal and based on the current second position information P B1 Obtaining the control parameters;
when the current first position information P A1 And the first initial calibration position information P A0 When the deviation of the above is larger than the second threshold value and smaller than the first threshold value, judging that the position of the quartz nitrate or the crucible is abnormal, and based on the actual deviation DeltaP A For the current first position information P A1 Compensating to obtain the control parameters;
when the current first position information P A1 And the first initial calibration position information P A0 When the deviation of the position of the quartz nitrate and the crucible is smaller than a first threshold value, judging that the positions of the quartz nitrate and the crucible are not abnormal, and based on the current first position information P A1 And obtaining the control parameters.
4. The single crystal growth apparatus of claim 2, wherein the third processing module is configured to specifically further:
will present second position information P B1 With the first initial calibration position information P B0 Comparing to judge whether the current position of the water cooling jacket is abnormal;
if so, based on the compensation parameter DeltaP C0 Current second position information P B1 And first initial calibration position information P A0 Calculating the actual offset delta P of the water-cooled jacket B And based on the actual offset DeltaP B For the current second position information P B1 And compensating.
5. The single crystal growth apparatus of claim 4, wherein the third processing module is configured to specifically further:
when the house is atThe current first position information P A1 And the first initial calibration position information P A0 And (3) when the deviation of the water cooling sleeve is larger than or equal to a third threshold value, judging whether the current position of the water cooling sleeve is abnormal or not.
6. The single crystal growing apparatus of claim 1, wherein the water jacket is configured to include at least two sub-water jackets, at least two of the sub-water jackets being nested with each other so that the water jacket is vertically retractable; the processing unit is further configured to control the water jacket to axially expand and contract to compensate the position of the crucible when the crucible is at an upper limit or a lower limit of its lifting stroke and the current position of the crucible does not reach a target position characterized by the control parameter.
7. A silicon melt level control method of a single crystal growth apparatus, characterized by being applied to the single crystal growth apparatus according to any one of claims 1 to 6, the method comprising:
collecting image information of a reflection image of the quartz nitrate measuring end on the liquid level of the silicon melt, and obtaining first position information P representing the liquid level position of the silicon melt based on the image information of the reflection image A The method comprises the steps of carrying out a first treatment on the surface of the Acquiring the image information of the calibration mark, and obtaining second position information P representing the liquid level position of the silicon melt based on the image information of the calibration mark B The method comprises the steps of carrying out a first treatment on the surface of the Based on the first position information P A And the second position information P B Obtaining control parameters for characterizing and controlling the lifting position of the crucible;
and controlling the crucible to lift based on the control parameter so as to control the position of the liquid level of the silicon solution.
8. The method according to claim 7, wherein the information based on the first position information P A And the second position information P B Obtaining control parameters for characterizing and controlling the lifting position of the crucible, wherein the control parameters specifically comprise:
based on the first initial calibration position information P A0 And second initial calibration position information P B0 Obtaining the compensation parameter delta P C0 Wherein the first initial calibration position information P A0 For the first position information when the distance between the silicon solution level and the measuring end of the quartz nitrate is the target gap value, the second initial calibration position information P B0 The second position information is the second position information when the distance between the liquid level of the silicon solution and the measuring end of the quartz nitrate is a target gap value;
will present the first position information P A1 And the first initial calibration position information P A0 Comparing to judge whether the current position of the quartz nitrate or the crucible is abnormal;
if so, based on the compensation parameter DeltaP C0 Current first position information P A1 And second initial calibration position information P B0 Calculating the actual offset DeltaP of the quartz nitro or the crucible A And based on the actual offset DeltaP A For the current first position information P A1 Compensating to obtain the control parameters; or based on the current second position information P B1 Obtaining the control parameters;
if not, based on the current first position information P A1 And obtaining the control parameters.
9. The method of claim 8, wherein if so, based on the compensation parameter Δp C0 Current first position information P A1 And second initial calibration position information P B0 Calculating the actual offset DeltaP of the quartz nitro or the crucible A And based on the actual offset DeltaP A For the current first position information P A1 Compensating to obtain the control parameters; or based on the current second position information P B1 Obtaining the control parameters; if not, based on the current first position information P A1 Obtaining the control parameters; the method specifically comprises the following steps:
when the current first position information P A1 And the first initial calibration position information P A0 Is of a deviation of (1)When the difference is greater than or equal to a first threshold value, judging that the quartz nitrate or the crucible is abnormal currently, and based on the current second position information P B1 Obtaining the control parameters;
when the current first position information P A1 And the first initial calibration position information P A0 When the deviation of the above is larger than the second threshold value and smaller than the first threshold value, judging that the position of the quartz nitrate or the crucible is abnormal, and based on the actual deviation DeltaP A For the current first position information P A1 Compensating to obtain the control parameters;
when the current first position information P A1 And the first initial calibration position information P A0 When the deviation of the position of the quartz nitrate and the crucible is smaller than a first threshold value, judging that the positions of the quartz nitrate and the crucible are not abnormal, and based on the current first position information P A1 And obtaining the control parameters.
10. The method according to claim 8, wherein the information based on the first position information P A And the second position information P B Obtaining control parameters for characterizing and controlling the lifting position of the crucible; in particular, the utility model also comprises the following components,
will present second position information P B1 With the first initial calibration position information P B0 Comparing to judge whether the current position of the water cooling jacket is abnormal;
if so, based on the compensation parameter DeltaP C0 Current second position information P B1 And first initial calibration position information P A0 Calculating the actual offset delta P of the water-cooled jacket B And based on the actual offset DeltaP B For the current second position information P B1 And compensating.
11. The method according to claim 7, characterized by being applied to the single crystal growth apparatus according to claim 6, the method further comprising:
and when the crucible is at the upper limit or the lower limit of the lifting stroke and the current position of the crucible does not reach the target position represented by the control parameter, controlling the water cooling jacket to axially stretch so as to compensate the position of the crucible.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311624696.0A CN117604605A (en) | 2023-11-30 | 2023-11-30 | Single crystal growth equipment and silicon melt liquid level position control method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311624696.0A CN117604605A (en) | 2023-11-30 | 2023-11-30 | Single crystal growth equipment and silicon melt liquid level position control method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117604605A true CN117604605A (en) | 2024-02-27 |
Family
ID=89949526
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311624696.0A Pending CN117604605A (en) | 2023-11-30 | 2023-11-30 | Single crystal growth equipment and silicon melt liquid level position control method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117604605A (en) |
-
2023
- 2023-11-30 CN CN202311624696.0A patent/CN117604605A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US9708731B2 (en) | Method of producing silicon single crystal | |
| US9260796B2 (en) | Method for measuring distance between lower end surface of heat insulating member and surface of raw material melt and method for controlling thereof | |
| CN109196144B (en) | Method and apparatus for manufacturing silicon single crystal | |
| KR101901308B1 (en) | Method for calculating height position of silicon melt surface, method for drawing up monocrystalline silicon and device for drawing up monocrystalline silicon | |
| JP6206178B2 (en) | Single crystal pulling method | |
| JP2013216505A (en) | Apparatus and method for manufacturing silicon single crystal | |
| JP5577873B2 (en) | Method for measuring distance between bottom surface of heat shield member and raw material melt surface, control method for distance between bottom surface of heat shield member and raw material melt surface, method for producing silicon single crystal | |
| JP2016121023A (en) | Production method of single crystal | |
| CN109750352B (en) | Method and apparatus for producing single crystal | |
| CN108138355B (en) | Single crystal manufacturing apparatus and method for controlling melt surface position | |
| JP4930487B2 (en) | Method for measuring distance between melt surface and lower end of in-furnace structure, method for controlling position of melt surface using the same, method for producing single crystal and single crystal production apparatus | |
| US20150197874A1 (en) | Device for growing monocrystalline silicon and method for manufacturing the same | |
| KR20220149755A (en) | Single crystal manufacturing apparatus and single crystal manufacturing method | |
| JP6645406B2 (en) | Single crystal manufacturing method | |
| CN110268105B (en) | Method for producing single crystal silicon, heat shield, and single crystal pulling apparatus | |
| CN117604605A (en) | Single crystal growth equipment and silicon melt liquid level position control method thereof | |
| JP6428372B2 (en) | Method for measuring distance between raw material melt surface and lower end of seed crystal, method for preheating seed crystal, and method for producing single crystal | |
| JP2019214486A (en) | Method of measuring interval between melt level and seed crystal, method of preheating seed crystal, and method of manufacturing single crystal | |
| JP2013216556A (en) | Method for pulling single crystal | |
| CN114134559B (en) | Single crystal manufacturing apparatus and single crystal manufacturing method | |
| KR20110086985A (en) | Melt temperature controlling system and the control method of the same | |
| JP2010095400A (en) | Device for pulling single crystal | |
| KR20230051263A (en) | Single crystal manufacturing method | |
| JP6090501B2 (en) | Single crystal pulling method | |
| CN116334745A (en) | Device and method for manufacturing monocrystalline silicon rod |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |