Nitrogen control system and method for semiconductor wafer nitrogen stocker

Abstract

The present application relates to gas replacement technical field, especially semiconductor wafer nitrogen gas Stocker's nitrogen control method, its technical scheme includes: nitrogen is transmitted from the upper part of technical interlayer, then is transmitted into STK warehouse through the exhaust filter, then carries out purification internal circulation, in this process, nitrogen is transported through nozzle equipment, manual valve, pneumatic valve, solenoid valve, temperature and humidity control meter adjusts temperature and humidity, in the process of nitrogen transportation, according to the air pressure of different positions in pipeline, B spline curve model is constructed, so as to judge whether nitrogen transportation is normal, in the process of monitoring nitrogen transportation condition, considering the roughness of pipeline inner wall and the loss of air pressure caused by the delivery angle and ventilation mode of pipeline, so as to express the air pressure change rule of nitrogen in the process of pipeline transportation by B spline curve model, difference curve is used as the index for evaluating nitrogen transportation condition, not only improve the accuracy of nitrogen transportation monitoring, also improve the convenience of evaluation.

Description

Technical Field

[0001] This invention relates to the field of gas displacement technology, and more particularly to a nitrogen control system and method for a nitrogen stocker for semiconductor wafers. Background Technology

[0002] Nitrogen is non-flammable, incompressible, and moisture-free, effectively preventing oxidation, moisture absorption, deterioration, or degradation of substances, and maintaining the original quality and durability of products. Therefore, nitrogen purging is crucial for the storage of semiconductor wafers. During nitrogen purging, monitoring temperature, humidity, oxygen concentration, and pressure effectively assesses nitrogen delivery status, allowing for timely control in case of abnormalities. However, the roughness of the pipe wall, the pipe's delivery angle, and the ventilation method can cause pressure loss, resulting in pressure variations at different locations within the pipe even under normal nitrogen delivery conditions. This can interfere with monitoring of nitrogen delivery status, leading to misjudgments.

[0003] In view of this, we propose a nitrogen control system and method for a semiconductor wafer nitrogen stocker to solve the existing problems. Summary of the Invention

[0004] The purpose of this invention is to provide a nitrogen control system and method for a nitrogen stocker on semiconductor wafers, in order to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a nitrogen control system for a semiconductor wafer nitrogen stocker, comprising a fan device, an exhaust filter, a STK chamber, a control valve component, a sensing device, a parameter calculation unit, a technical interlayer, a nozzle device, and a pipeline; wherein, the parameter calculation unit includes a curve construction unit, a control point calculation unit, and a judgment unit.

[0006] Furthermore, the control valve component includes a manual valve, a pneumatic valve, and a solenoid valve.

[0007] Furthermore, the sensing device includes a flow meter, an oxygen concentration meter, a temperature and humidity controller, and a pressure gauge, and several of the flow meter, oxygen concentration meter, temperature and humidity controller, and pressure gauge are installed at different positions inside the pipeline.

[0008] Furthermore, it also includes filters, regulators, pressure switches, and one-touch connectors.

[0009] Furthermore, the exhaust filter is provided in several parts, divided into two parts, designated as the first exhaust filter and the second exhaust filter.

[0010] The nitrogen control method for a semiconductor wafer nitrogen stocker, according to the nitrogen control system of the semiconductor wafer nitrogen stocker, the nitrogen replacement method includes: nitrogen is introduced from above the technical interlayer, then introduced into the STK storage body through the exhaust filter, and then purified and circulated internally.

[0011] Furthermore, the STK storage chamber is under negative pressure.

[0012] Furthermore, nitrogen is delivered through nozzle devices, manual valves, pneumatic valves, and solenoid valves, while temperature and humidity are regulated by a temperature and humidity controller.

[0013] Furthermore, during the nitrogen transport process, a B-spline curve model is constructed based on the gas pressure at different locations within the pipeline, and control points are determined.

[0014] Furthermore, a complete B-spline curve is obtained based on the control points to determine whether the nitrogen supply is normal.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] This invention introduces nitrogen gas from above the technical interlayer, then through an exhaust filter into the STK storage tank, where it undergoes purification and internal circulation. During this process, nitrogen is delivered via nozzles, manual valves, pneumatic valves, and solenoid valves. Temperature and humidity are regulated by a temperature and humidity controller. A B-spline curve model is constructed based on the gas pressure at different locations within the pipeline to determine if the nitrogen delivery is normal. In monitoring nitrogen delivery, the roughness of the pipeline inner wall, the pipeline delivery angle, and the ventilation method all contribute to pressure loss. Therefore, a B-spline curve model is used to represent the pressure change pattern of nitrogen during pipeline delivery, with the difference curve serving as an indicator for evaluating nitrogen delivery. This not only improves the accuracy of nitrogen delivery monitoring but also enhances the convenience of evaluation. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the nitrogen replacement process of the nitrogen control method for the nitrogen stocker on semiconductor wafers according to the present invention.

[0018] Figure 2 This is a schematic diagram of the nitrogen delivery process for the nitrogen control method of the semiconductor wafer nitrogen stocker of the present invention;

[0019] Figure 3 This is a schematic diagram of normal nitrogen emission in the nitrogen control method of the semiconductor wafer nitrogen stocker of the present invention.

[0020] Figure 4 This is a schematic diagram of nitrogen countercurrent emission in the nitrogen control method of the semiconductor wafer nitrogen stocker of the present invention. Detailed Implementation

[0021] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0022] Example 1

[0023] The nitrogen control system for a semiconductor wafer nitrogen stocker includes a fan unit, exhaust filters, STK chamber, control valve components, sensors, parameter calculation units, technical interlayer, nozzle devices, piping, filters, regulators, pressure switches, and one-button connectors. The parameter calculation unit includes a curve construction unit, a control point calculation unit, and a judgment unit. The control valve components include manual valves, pneumatic valves, and solenoid valves. The sensors include flow meters, oxygen concentration meters, temperature and humidity controllers, and pressure gauges, with multiple flow meters, oxygen concentration meters, temperature and humidity controllers, and pressure gauges located at different positions within the piping. Several exhaust filters are provided, divided into two parts: a first exhaust filter and a second exhaust filter.

[0024] like Figure 1 As shown, in the nitrogen control method of the semiconductor wafer nitrogen stocker, the nitrogen replacement method includes: nitrogen is introduced from above the technology interlayer, then enters the STK storage body through an exhaust filter, and then undergoes internal purification and circulation. Exhaust can be activated when necessary. For safety reasons, the STK storage body is kept under negative pressure to prevent nitrogen leakage.

[0025] like Figure 2 As shown, during the nitrogen delivery process, the nitrogen first passes through a manual valve, then a flow meter to monitor the nitrogen flow rate in real time, then a pneumatic valve, then a filter to filter out and suppress interference and noise signals, then a regulator to monitor the circuit in real time to ensure stable voltage and current, then a pressure gauge and a pressure switch. The pressure switch is used to monitor and control the gas pressure, and the pressure gauge displays the gas pressure. Finally, the nitrogen is input into the STK storage body through the first exhaust filter. This delivery path is set as the first delivery path.

[0026] If the air pressure in the first delivery path is abnormal, adjust the pneumatic valve to change the nitrogen delivery path so that the nitrogen passes through the solenoid valve. The one-button connector connects the solenoid valve to the second exhaust filter so that the nitrogen enters the STK storage body through the second exhaust filter. This delivery path is then set as the second delivery path.

[0027] like Figure 3As shown, when nitrogen needs to be released, the nitrogen is discharged from the STK storage chamber to the pipeline under the action of the STK exhaust fan. If the gas pressure of other equipment is normal, the gas is transported towards the main exhaust fan, and under the action of the main exhaust fan, the nitrogen is discharged to the outside through the pipeline. The discharge is considered complete when the nitrogen concentration in the storage chamber is the same as the nitrogen concentration in the air.

[0028] like Figure 4 As shown, if the gas pressure of other equipment is abnormal, nitrogen will flow back to other equipment. The pressure gauge can monitor the gas pressure in the pipeline in real time, and will deal with any abnormalities in a timely manner.

[0029] The working principle of the nitrogen control system and method based on the semiconductor wafer nitrogen stocker in Example 1 is as follows:

[0030] The static pressure airflow characteristic curve reflects the airflow variation of the fan under different static pressures. During system operation, by monitoring the changes in static pressure and airflow, the system performance can be evaluated to determine whether it meets the design requirements, facilitating timely adjustment and maintenance.

[0031] Temperature and humidity controllers are used to monitor and control the temperature and humidity inside pipelines. They collect temperature and humidity data from the pipeline through sensors and then automatically control equipment such as air conditioners, heaters, and dehumidifiers according to preset ranges to maintain the stability of temperature and humidity inside the pipeline.

[0032] When the initial nitrogen concentration in the STK storage chamber is 78%, if the supplied nitrogen concentration is 95%, the number of replacement cycles reaches 4, and the oxygen concentration in the chamber consistently decreases to 5%; if the supplied nitrogen concentration is 99%, the number of replacement cycles reaches 6, and the oxygen concentration in the chamber consistently decreases to 1%; if the supplied nitrogen concentration is 99.5%, the number of replacement cycles reaches 7, and the oxygen concentration in the chamber consistently decreases to 0.5%; if the supplied nitrogen concentration is 99.9%, the number of replacement cycles reaches 9, and the oxygen concentration in the chamber consistently decreases to 0.1%; if the supplied nitrogen concentration is 99.99%, the number of replacement cycles reaches 11, and the oxygen concentration in the chamber consistently decreases to 0.01%; if the supplied nitrogen concentration is 99.999%, the number of replacement cycles reaches 8, and the oxygen concentration in the chamber decreases to 0.01%. The number of replacement cycles is a multiple of the volume of the transported gas relative to the container volume.

[0033] The initial mass flow rate of the replacement is m f The unit is kg / s. Where 'a' is the area of ​​the nozzle cross-section. d is the diameter of the nozzle cross-section; P1 is the absolute pressure, i.e., the sum of gauge pressure and 0.101 MPa; c is the flow coefficient, set to 100%, i.e., 1; T1 is the absolute temperature, i.e., the sum of Celsius temperature and 273, in K; R is the gas constant, set to 287, in J / (kg·K); γ is the specific heat ratio, set to 1.4. Therefore,

[0034] The initial displacement volumetric flow rate is Q, in L / min. Where 1.2 is the specific gravity of air at 20℃, in kg / m³. 3 .

[0035] The gas mass is M, M = Q1 × ρ; where Q1 is the normal flow rate in m³ / s. 3 ρ is the gas density, in kg / m³. 3 . Q0 represents the measured flow rate, in cubic meters per second (m³). 3 P represents the measured pressure in MPa; T represents the measured temperature in °C.

[0036] The roughness of the inner wall of the pipeline, the pipeline's transport angle, and the ventilation method will cause pressure loss, resulting in different pressures at different locations in the pipeline under normal nitrogen transport conditions. The pressure change pattern of nitrogen during pipeline transport is represented by a B-spline curve model.

[0037] The algorithm formula for an nth-degree B-spline curve with m segments is as follows:

[0038]

[0039] In the formula: P i,n (t) represents the value of the i-th segment after n B-spline curve transformations, where i = 1, 2, 3, ..., m; t represents the value before the B-spline curve transformation. For each point in the curve segment, 0 ≤ t ≤ 1 is satisfied, where t = 0 represents the first node of the i-th segment, and t = 1 represents the last node of the i-th segment; p i+k-1 F represents the control point of the i-th segment of the B-spline curve; k,n (t) is a piecewise mixed function of an nth-degree B-spline curve, where 0 ≤ t ≤ 1 and k = 0, 1, 2, ..., n.

[0040] Let G be the set of measured gas pressures at different locations within the pipeline under normal gas transport conditions. Digitize the different locations of the measured gas pressures within the pipeline, and let L be the set of these locations. Construct a B-spline curve model as F(L)·P=G, where F(L) is the set of piecewise mixed functions of L, and P is the set of standard control points for the B-spline curve model. Use this model to calculate P. Let L be the digitized set of all locations within the pipeline. T According to P and L TFind the set of air pressures G at all locations inside the pipe. Total =F(L T )·P.

[0041] During nitrogen purging, pressure gauges at different locations within the pipeline measure the current gas pressure. The curve construction unit constructs a B-spline curve model based on the pressure readings from these gauges and the corresponding values ​​at the current location. The control point calculation unit then calculates the set of control points P based on the constructed B-spline curve model. T Based on the obtained set of control points P T With L T Find the set of air pressures G at all locations inside the pipe. Test =F(L T )·P T .

[0042] The judgment unit is based on G Total With G Test Find the difference curve D(L) T )=|G Test -G Total |=|F(L T )·(P T -P), if the values ​​of the difference curves are all below the set threshold, the gas delivery is considered normal; if the values ​​of the difference curves reach or exceed the set threshold, the gas delivery is considered abnormal, and timely maintenance is performed based on the digital position corresponding to the abnormal difference value.

[0043] The above specific embodiments are merely several preferred embodiments of the present invention. Based on the technical solutions of the present invention and the relevant teachings of the above embodiments, those skilled in the art can make various alternative improvements and combinations to the above specific embodiments.

Claims

1. A nitrogen control system for a semiconductor wafer nitrogen stocker, characterized in that: It includes a fan unit, an exhaust filter, an STK chamber, control valve components, a sensor, a parameter calculation unit, a technical interlayer, nozzle equipment, and piping; wherein, the parameter calculation unit includes a curve construction unit, a control point calculation unit, and a judgment unit; Nitrogen gas is delivered via nozzle equipment, manual valves, pneumatic valves, and solenoid valves, while temperature and humidity are regulated by a temperature and humidity controller. During the nitrogen delivery process, a B-spline curve model is constructed based on the gas pressure at different locations within the pipeline, and control points are determined. A complete B-spline curve is then obtained based on the control points to determine whether the nitrogen delivery is normal. The roughness of the inner wall of the pipeline, the pipeline's delivery angle, and the ventilation method will cause pressure loss, resulting in different pressures at different locations in the pipeline under normal nitrogen delivery conditions. The pressure change pattern of nitrogen during pipeline delivery is represented by a B-spline curve model. The algorithm formula for an nth-degree B-spline curve with m segments is as follows: ； In the formula: P i,n (t) represents the value of the i-th segment after n B-spline curve transformations, where i = 1, 2, 3, ..., m; t represents the value before the B-spline curve transformation. For each point in the curve segment, 0 ≤ t ≤ 1 is satisfied, where t = 0 represents the first node of the i-th segment, and t = 1 represents the last node of the i-th segment; p i+k-1 F represents the control point of the i-th segment of the B-spline curve; k,n (t) is a piecewise mixing function of an nth-order B-spline curve, where 0 ≤ t ≤ 1, k = 0, 1, 2, ..., n; Let G be the set of measured gas pressures at different locations within the pipeline when gas transport is normal. Digitize the different locations of the measured gas pressures within the pipeline, and let L be the set of these locations. Construct a B-spline curve model as F(L)·P = G, where F(L) is the set of piecewise mixed functions of L, and P is the set of standard control points for the B-spline curve model. Calculate P using this model. Let L be the digitized set of all locations within the pipeline. T According to P and L T Find the set of air pressures G at all locations inside the pipe. Total = F(L T )·P; During nitrogen purging, pressure gauges at different locations within the pipeline measure the current gas pressure. The curve construction unit constructs a B-spline curve model based on the pressure readings from these gauges and the corresponding values ​​at the current location. The control point calculation unit then calculates the set of control points P based on the constructed B-spline curve model. T Based on the obtained set of control points P T With L T Find the set of air pressures G at all locations inside the pipe. Test = F(L T )·P; The judgment unit is based on G Total With G Test Find the difference curve D(L) T ) = |G Test - G Total | = |F(L T )·(P T If the values ​​of the difference curves are all below the set threshold, the gas delivery is considered normal; if the values ​​of the difference curves reach or exceed the set threshold, the gas delivery is considered abnormal, and timely maintenance is performed based on the digitized position corresponding to the abnormal difference value.

2. The nitrogen control system for the semiconductor wafer nitrogen stocker according to claim 1, characterized in that: The control valve components include manual valves, pneumatic valves, and solenoid valves.

3. The nitrogen control system for the semiconductor wafer nitrogen stocker according to claim 1, characterized in that: The sensing device includes a flow meter, an oxygen concentration meter, a temperature and humidity controller, and a pressure gauge. Several of each of the flow meter, oxygen concentration meter, temperature and humidity controller, and pressure gauge are installed at different locations within the pipeline.

4. The nitrogen control system for the semiconductor wafer nitrogen stocker according to claim 1, characterized in that: It also includes filters, regulators, pressure switches, and one-touch connectors.

5. The nitrogen control system for the semiconductor wafer nitrogen stocker according to claim 1, characterized in that: The exhaust filter consists of several parts, divided into two parts: the first exhaust filter and the second exhaust filter.

6. A nitrogen control method for a semiconductor wafer nitrogen stocker, comprising a nitrogen control system for a semiconductor wafer nitrogen stocker according to any one of claims 1-5, characterized in that, The nitrogen replacement method includes: nitrogen is introduced from above the technical interlayer, then introduced into the STK storage body through an exhaust filter, and then purified and recirculated internally.

7. The nitrogen control method for a semiconductor wafer nitrogen stocker according to claim 6, characterized in that: The STK storage chamber is under negative pressure.

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