A method for extracting contaminants in a wafer box

Abstract

The present invention provides a method for extracting contaminants from a wafer cassette, comprising: step S1: adding a solvent to the wafer cassette, wherein the volume of the solvent is 5% to 20% of the volume of the wafer cassette; step S2: adjusting the wafer cassette to a first state, with the first surface of the wafer cassette horizontal and upward, and rotating the wafer cassette about an axis to clean four surfaces including the first surface; step S3: adjusting the wafer cassette to a second state, with the first surface vertical, and rotating the wafer cassette about the axis to clean the remaining two surfaces; step S4: adjusting the wafer cassette to a third state, with the first surface tilted, and rotating the wafer cassette about the axis to clean a predetermined area; and step S5: removing the solvent, analyzing, and calculating the contaminant content level. This method has the following beneficial technical effects: low solvent / extraction liquid usage, cost savings, and the ability to accurately adjust the cleaning process in real time, achieving uniform extraction / cleaning standards for wafer cassettes.

Description

Technical Field

[0001] The method of the present invention belongs to the field of cleaning wafer boxes used in integrated circuit manufacturing, and in particular relates to a method for extracting / cleaning pollutants in a wafer box, which improves cleaning effect and saves cleaning time. Background Art

[0002] During the integrated circuit manufacturing process, a large number of wafer boxes are required to transport wafers. Because the manufacturing process uses a variety of different types of chemicals such as doping ions, pollutants accumulate in the wafer boxes. After a batch of integrated circuit products is completed, the wafer boxes used in the process need to be cleaned before being used in the manufacturing of the next batch of integrated circuit products.

[0003] Liquid contaminants in wafer cassettes primarily include metallic impurities, anionic impurities, and particulate contaminants. Existing methods for detecting liquid contaminants in wafer cassettes primarily rely on manual or semi-manual full-immersion extraction methods. This involves rinsing the interior of the cassette with a large amount of solvent, then sampling the cassette for contaminant index testing. Since wafer cassettes are used to store and transport wafers in integrated circuit manufacturing, the amount of contaminants within the cassette directly impacts wafer transportation. To avoid contamination of the wafers, the cassettes are cleaned of contaminants and then tested for acceptable levels of contaminants. Wafer cassettes with reduced contaminants for use in the next round of integrated circuit manufacturing are selected. Most wafer cassettes used in existing integrated circuit manufacturing plants are approximately cube-shaped and have a large internal volume. This full-immersion extraction method presents the following issues.

[0004] First, the full immersion extraction method requires a large amount of solvent / extraction liquid, which wastes the solvent / extraction liquid and is costly. In addition, due to the full immersion method, the extraction method that can be adopted is static and dynamic extraction is not possible.

[0005] Second, fully manual or semi-manual extraction cleaning cannot achieve standardized cleaning. It requires manual real-time testing of the contaminant level in the extraction cleaning fluid to ensure that the contaminants in the wafer cassette are reduced to acceptable levels, making the cleaning process complex.

[0006] Third, without adopting program control measures, the extraction and cleaning mode cannot be accurately adjusted in real time. The cleaning operation wastes time and the cleaning degree varies, which easily affects the uniformity and yield of the same batch of integrated circuit products. Summary of the Invention

[0007] In order to solve the above technical problems, the present invention provides a method for extracting / cleaning pollutants in a wafer box with an optimal solvent usage and cleaning process, which can achieve low solvent / extraction liquid volume, save costs, and use a program to accurately adjust the cleaning process in real time to achieve unified standard cleaning for all wafer boxes.

[0008] The present invention provides a method for cleaning contaminants in a simulated wafer box, comprising:

[0009] Step 100: Determine the cleaning elements of the wafer cassette, including the area elements of each inner surface of the wafer cassette, the edge elements, the relationship between the edge elements and the area elements, and the solvent elements;

[0010] Step 200: Input the cleaning elements to simulate the cleaning process so that the cleaning degrees of n points on the inner surface of the wafer cassette are the same;

[0011] Step 300: Stop the simulation when the conditions are met.

[0012] The cleaning process includes the amount of solvent, the path of the solvent passing through n points on the inner surface of the wafer cassette, the pressure of the solvent on n points on the inner surface of the wafer cassette, the effective amount of the cleaning component of the solvent in the process, the number of cleaning times, and the relationships formed between any two or more of them;

[0013] The number of cleaning times at least includes the number of cycles of solvent cleaning;

[0014] The conditions at least include the reduction of the cleaning amount increment.

[0015] Preferably, Step 200 includes that the cleaning process after the r-th cleaning of the n-th point satisfies formula (1):

[0016] Qnr = ∑qnr{a1*f(d, vnr), a2*s(vnr, r, r’), a3*e(d, r, r’)}

[0017] Q1r = Q2r = Q3r = … Qnr (1)

[0018] Where r is the number of cleaning times, r is a natural number greater than or equal to 2, e(d, r, r’) < e(d, r - 1, r - 1’); qnr is the cleaning amount of the solvent for the n-th point in the r-th cleaning, qnr is the functional relationship between the pressure f of the solvent for the n-th point in the r-th cleaning, the path s of the solvent passing through the n-th point, and the effective amount e of the cleaning component of the solvent for the n-th point in the r-th cleaning, f is a function of the amount of solvent d and the r-th velocity vnr, s is a function of the r-th velocity vnr and the number of cleaning times r, e is a function of the amount of solvent d, the number of cleaning times r, and the redundancy amount of times r’, a1, a2, and a3 are respectively the weight relationships between the pressure f of the solvent for the n-th point in the r-th cleaning, the path s of the solvent passing through the n-th point, and the effective amount e of the cleaning component of the solvent for the n-th point in the r-th cleaning, a1 + a2 + a3 = 1 or the value ranges of a1, a2, and a3 are 0.1 to 10.

[0019] Preferably, the conditions include that qnr, qnr-1, and qnr-2 satisfy formula (2):

[0020] a5*qnr-2 = qnr + a4*qnr-1 (2)

[0021] Where qnr is the cleaning amount of the solvent at the nth point after the rth cleaning, qnr-1 is the cleaning amount of the solvent at the nth point after the r-1th cleaning, and qnr-2 is the cleaning amount of the solvent at the nth point after the r-2th cleaning; a5 ranges from 0.01 to 0.2, and a4 ranges from 0.1 to 0.3; or, a4 and a5 are both positive numbers less than 1, satisfying a5 = 1 / 2 * a4 2 .

[0022] Preferably, the cleaning process further includes a first state of cleaning four surfaces of the wafer box and a second state of cleaning the remaining two surfaces of the wafer box.

[0023] Preferably, the first state is that the wafer box rotates vertically to clean the four surfaces, and the second state is that the wafer box rotates horizontally to clean the two surfaces; the cleaning process satisfies formula (3):

[0024] ak=Qi / Qii

[0025] Qi=q{a6*f(d,vi),a6*s(vi),a8*e(d,s)}

[0026] Qii=q{a6*f(d,vii),a7*s(vii),a8*e(d,s)} (3)

[0027] Among them, the value range of a is 0.1~10, k is the cleaning area ratio of the first state to the second state, Qi is the cleaning degree in the first state, and Qii is the cleaning degree in the second state; the pressure f of the solvent on the inner surface of the wafer box is a function of the solvent amount d and the solvent speed v, the solvent distance s is a function of the solvent speed v, and the effective amount of cleaning component e is a function of the solvent amount d and the distance s; a6, a7, and a8 are the weight relationships between the pressure f of the solvent on the inner surface of the wafer box, the distance s traveled by the solvent, and the effective amount of solvent cleaning component e, respectively, a6+a7+a8=1 or the value range of a6, a7, and a8 is 0.1~10.

[0028] Preferably, the first state is executed before the second state, e(d, s(vi))≥e(d, s(vii)).

[0029] Preferably, the second state is executed before the first state, e(d, s(vi))≤e(d, s(vii)).

[0030] Preferably, the cleaning process further includes a third state for cleaning the edges, and the duration of the third state is shorter than that of the second state or the first state.

[0031] Preferably, the wafer box has only one initial rotation position in the second state, and has several initial rotation positions in the first state and the third state.

[0032] Preferably, in the first state, the second state or the third state, the wafer box is rotating in the container; or, the wafer box is connected to the rotating structure through its own components and rotates.

[0033] A method for extracting contaminants from a wafer box based on the above simulation is also provided, comprising:

[0034] Step S1: adding solvent into the wafer box;

[0035] Step S2: adjusting the wafer cassette to a first state, with the first surface of the wafer cassette horizontal and facing upward, and rotating the wafer cassette around an axis to clean four surfaces including the first surface;

[0036] Step S3: Adjust to the second state, make the first surface vertical, rotate the wafer box around the axis, and clean the remaining two surfaces:

[0037] Step S4: adjusting to a third state, tilting the first surface, and rotating the wafer box around the axis to clean a predetermined area;

[0038] Step S5: removing the solvent, analyzing and calculating the contaminant content level;

[0039] The first state and the third state have a plurality of initial rotation positions, the third state has a plurality of intermediate rotation positions, and the first state, the second state, and the third state enable n points on the inner surface of the wafer box to be cleaned to the same degree;

[0040] The execution order of steps S2, S3 and S4 is any one of the permutations and combinations of S2, S3 and S4.

[0041] Preferably, the first surface is the top surface of the wafer box.

[0042] Preferably, the predetermined area at least includes an edge portion and / or a portion of a surface formed by the edge portion.

[0043] Preferably, in step S1, the wafer box is placed with the first surface facing upward, and solvent is added into the wafer box, the amount of solvent at least immersing the bottom surface opposite to the first surface, or the amount of solvent at least immersing the edge of the bottom surface opposite to the first surface.

[0044] Preferably, the duration of the first state and the second state is related to the ratio of the cleaned areas.

[0045] Preferably, the first state is that the wafer box rotates vertically to clean the four surfaces, and the second state is that the wafer box rotates horizontally to clean the two surfaces; the cleaning process satisfies formula (3):

[0046] ak=Qi / Qii

[0047] Qi=q{a6*f(d,vi),a6*s(vi),a8*e(d,s)}

[0048] Qii=q{a6*f(d,vii),a7*s(vii),a8*e(d,s)} (3)

[0049] Among them, the value range of a is 0.1~10, k is the cleaning area ratio of the first state to the second state, Qi is the cleaning degree in the first state, and Qii is the cleaning degree in the second state; the pressure f of the solvent on the inner surface of the wafer box is a function of the solvent amount d and the solvent speed v, the solvent distance s is a function of the solvent speed v, and the effective amount of cleaning component e is a function of the solvent amount d and the distance s; a6, a7, and a8 are the weighted relationships between the pressure f of the solvent on the inner surface of the wafer box in the first state or the second state, the distance s traveled by the solvent, and the effective amount of solvent cleaning component e, respectively, a6+a7+a8=1 or the value range of a6, a7, and a8 is 0.1~10.

[0050] Preferably, a6=a8=0, the distances traveled by the solvent in the first state and the second state are equal, and the cleaning degree Qi in the first state and the cleaning degree Qii in the second state can be respectively expressed as:

[0051] Qi=s(vi)=∫vitidt

[0052] Qii=s(vii)=∫viitiidt

[0053] Among them, s(vi) and s(vii) are the distances traveled by the solvent in the first state and the second state respectively, vi and vii are the speeds of the solvent in the first state and the second state respectively, and ti and tii are the duration of the first state and the second state respectively.

[0054] Preferably, step S2 is performed before step S3, e(d,s(vi))≥e(d,s(vii)); or,

[0055] Step S3 is executed before step S2, and e(d, s(vi))≤e(d, s(vii)).

[0056] Preferably, the cleaning process of the nth point after the rth cleaning satisfies formula (1):

[0057] Qnr = ∑qnr{a1*f(d, vnr), a2*s(vnr, r, r’), a3*e(d, r, r’)}

[0058] Q1r = Q2r = Q3r = … Qnr (1)

[0059] Where r is the number of cleaning times, r is a natural number greater than or equal to 2, and e(d, r, r’) < e(d, r - 1, r - 1’); qnr is the cleaning amount of the solvent for the r-th cleaning of the n-th point, qnr is the functional relationship of the pressure f of the solvent for the r-th cleaning of the n-th point, the path s of the solvent passing through the n-th point, and the effective amount e of the cleaning component of the solvent for the r-th cleaning of the n-th point. f is a function of the solvent amount d and the r-th speed vnr, s is a function of the r-th speed vnr and the cleaning times r, e is a function of the solvent amount d, the cleaning times r, and the redundancy amount r’ of the times. a1, a2, and a3 are the weight relationships between the pressure f of the solvent for the r-th cleaning of the n-th point, the path s of the solvent passing through the n-th point, and the effective amount e of the cleaning component of the solvent for the r-th cleaning of the n-th point, respectively, and a1 + a2 + a3 = 1 or the value ranges of a1, a2, and a3 are 0.1 to 10.

[0060] Preferably, when qnr, qnr - 1, and qnr - 2 in steps S2, S3, and S4 satisfy formula (2), the cleaning ends:

[0061] a5*qnr - 2 = qnr + a4*qnr - 1 (2)

[0062] Where qnr is the cleaning amount of the solvent for the r-th cleaning of the n-th point, qnr - 1 is the cleaning amount of the solvent for the (r - 1)-th cleaning of the n-th point, and qnr - 2 is the cleaning amount of the solvent for the (r - 2)-th cleaning of the n-th point; the value range of a5 is 0.01 to 0.2, and the value range of a4 is 0.1 to 0.3; or, a4 and a5 are both positive numbers less than 1, and satisfy a5 = 1 / 2*a4 2 .

[0063] To implement the above extraction cleaning method, a device for extracting contaminants from a wafer cassette is also provided, including a controller, a power device controlled by the controller, a rotating shaft, and a connecting shaft; characterized in that it further includes

[0064] A universal joint for the connecting shaft to slide therein to control the connecting shaft to freely switch directions in the hemispherical direction;

[0065] The connecting shaft is connected to the wafer cassette and is driven by the power device to make the wafer cassette rotate around the axis of the rotating shaft; the universal joint includes:

[0066] A vertical groove to control the connecting shaft to slide in the vertical direction to realize the rotation of the wafer cassette in the first state;

[0067] Horizontal slot to control the connecting shaft to slide in the horizontal direction to achieve the second state of rotating wafer box:

[0068] Inclined groove to control the connecting shaft to slide in an inclined direction to achieve the third state of rotating the wafer box:

[0069] The first state is that the wafer box is rotated around the axis with the first surface horizontal and facing upward to clean four surfaces including the first surface;

[0070] The second state is to make the first surface vertical, rotate the wafer box around the axis, and clean the remaining two surfaces;

[0071] The third state is to tilt the first surface and rotate the wafer box around the axis to clean a predetermined area;

[0072] The first state and the third state have a plurality of initial rotation positions, the third state has a plurality of intermediate rotation positions, and the first state, the second state and / or the third state enable n points on the inner surface of the wafer box to be cleaned to the same degree;

[0073] The rotating shaft is fixedly connected to the universal joint, and the power device drives the rotating shaft to rotate around its axis and drives the universal joint and the connecting shaft located in the universal joint to rotate. Alternatively, it also includes a control shaft and a control device that are coaxial with the rotating shaft and fixedly connected to each other. The control device is rotatably connected to the connecting shaft and allows the connecting shaft to freely change direction in a hemispherical space. The power device drives the control shaft to rotate and drives the connecting shaft and even the wafer box to rotate around the axis.

[0074] Preferably, the universal guide is in a sheet or semicircular shape.

[0075] Preferably, a connecting groove is further included to connect the vertical groove, the horizontal groove and the inclined groove.

[0076] Preferably, the vertical slot, the horizontal slot or the inclined slot includes a positioning structure that cooperates with the connecting shaft to fix the direction.

[0077] Preferably, the first surface is the top surface of the wafer box.

[0078] Preferably, the predetermined area at least includes an edge portion, and / or a portion of both sides of the edge portion.

[0079] Preferably, the controller controls so that the relationship between the cleaning degree in the first state and the cleaning degree in the second state is related to the ratio of the cleaned areas; and the cleaning process satisfies formula (3):

[0080] ak=Qi / Qii

[0081] Qi=q{a6*f(d,vi),a6*s(vi),a8*e(d,s)}

[0082] Qii=q{a6*f(d,vii),a7*s(vii),a8*e(d,s)} (3)

[0083] Among them, the value range of a is 0.1~10, k is the cleaning area ratio between the first state and the second state, Qi is the cleaning amount in the first state, and Qii is the cleaning amount in the second state; the pressure f of the solvent on the inner surface of the wafer box is a function of the solvent amount d and the solvent speed v, the solvent distance s is a function of the solvent speed v, and the effective amount of cleaning component e is a function of the solvent amount d and the distance s; a6, a7, and a8 are the weighted relationships between the pressure f of the solvent on the inner surface of the wafer box in the first state or the second state, the distance s traveled by the solvent, and the effective amount of solvent cleaning component e, respectively, a6+a7+a8=1 or the value range of a6, a7, and a8 is 0.1~10.

[0084] Preferably, a6=a8=0, the distances traveled by the solvent in the first state and the second state are equal, and the respective cleaning degrees Qi and Qii can be expressed as:

[0085] Qi=s(vi)=∫vitidt,

[0086] Qii=s(vii)=∫viitiidt;

[0087] Among them, s(vi) and s(vii) are the distances traveled by the solvent in the first state and the second state respectively, vi and vii are the speeds of the solvent in the first state and the second state respectively, and ti and tii are the duration of the first state and the second state respectively.

[0088] Preferably, the first state is executed before the second state, e(d,s(vi))≥e(d,s(vii)); or,

[0089] The second state is executed before the first state, e(d, s(vi))≤e(d, s(vii)).

[0090] Preferably, the controller controls so that the cleaning process of the nth point after the rth cleaning satisfies formula (1):

[0091] Qnr=Σqnr{a1*f(d,vnr),a2*s(vnr,r,r'),a3*e(d,r,r')}

[0092] Q1r = Q2r = Q3r = … Qnr (1)

[0093] Where r is the number of cleaning times, r is a natural number greater than or equal to 2, and e(d, r, r’) < e(d, r - 1, r - 1’); qnr is the cleaning amount of the solvent for the r-th cleaning of the n-th point. qnr is a functional relationship of the pressure f of the solvent for the r-th cleaning of the n-th point, the path s of the solvent passing through the n-th point, and the effective amount e of the cleaning component of the solvent for the r-th cleaning of the n-th point. f is a function of the solvent amount d and the r-th velocity vnr, s is a function of the r-th velocity vnr and the number of cleaning times r, e is a function of the solvent amount d, the number of cleaning times r, and the redundancy amount r’ of the times. a1, a2, and a3 are respectively the weight relationships between the pressure f of the solvent for the r-th cleaning of the n-th point, the path s of the solvent passing through the n-th point, and the effective amount e of the cleaning component of the solvent for the r-th cleaning of the n-th point, and a1 + a2 + a3 = 1 or the value ranges of a1, a2, and a3 are 0.1 to 10;

[0094] When qnr, qnr - 1, and qnr - 2 in the first state, the second state, and the third state satisfy formula (2), the cleaning ends:

[0095] a5 * qnr - 2 = qnr + a4 * qnr - 1 (2)

[0096] Where qnr is the cleaning amount of the solvent for the r-th cleaning of the n-th point, qnr - 1 is the cleaning amount of the solvent for the (r - 1)-th cleaning of the n-th point, and qnr - 2 is the cleaning amount of the solvent for the (r - 2)-th cleaning of the n-th point; the value range of a5 is 0.01 to 0.2, and the value range of a4 is 0.1 to 0.3; or a4 and a5 are both positive numbers less than 1, and a5 = 1 / 2 * a4 2 .

[0097] The present invention provides a method for extracting contaminants in a wafer cassette, with low usage of solvent / extraction liquid, cost savings, real-time and precise adjustment of the cleaning process achievable, and unified standard extraction / cleaning for all wafer cassettes realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0098] Attached Figure 1 is a flowchart of the method for extracting contaminants in the wafer cassette using the present invention;

[0099] Attached Figure 2 is a schematic diagram of the first state of the device for extracting contaminants in the wafer cassette of the present invention;

[0100] Attached Figure 3 is a schematic diagram of the second state of the device for extracting contaminants in the wafer cassette of the present invention;

[0101] Attached Figure 4 is a schematic diagram of the third state of the device for extracting contaminants in the wafer cassette of the present invention;

[0102] Attachment Figure 5 is a flow chart of a method for cleaning contaminants in a simulated wafer box according to the present invention;

[0103] Attachment Figure 6a It is a schematic diagram of a universal device for extracting contaminants from a wafer box according to the present invention;

[0104] Attachment Figure 6b It is a schematic diagram of another universal device of the device for extracting contaminants in a wafer box of the present invention;

[0105] Attachment Figure 6c It is attached Figure 6a and Figure 6b Schematic diagram of the right-side projection of the central gimbal;

[0106] Attachment Figure 6d It is attached Figure 6c A magnified schematic diagram of the positioning structure;

[0107] Attachment Figure 6e It is attached Figure 6d Schematic diagram of the positioning structure used in conjunction with each other;

[0108] Attachment Figure 6f It is attached Figure 6d Schematic diagram of the three-dimensional structure of the connecting shaft part containing positioning accessories. DETAILED DESCRIPTION

[0109] The following describes in detail the specific embodiments of the method for cleaning contaminants in a simulated wafer box, the method for extracting contaminants in a wafer box, and the device for extracting contaminants in a wafer box to implement the method according to the present invention with reference to the accompanying drawings.

[0110] In the accompanying drawings, for the sake of convenience, the size ratios of layers and regions are not actual ratios. It should be noted that the illustrations provided in this embodiment are only schematic illustrations of the basic concept of the present invention. Therefore, the drawings only show components related to the present invention and are not drawn according to the number, shape and size of components in actual implementation. The type, quantity and ratio of each component in actual implementation can be said to be a random change, and the component layout type may also be more complex. In addition, when two components are referred to as "connected", it includes a physical connection. Unless otherwise specified in the specification, such physical connection includes but is not limited to electrical connection, contact connection, and wireless signal connection.

[0111] like Figure 5 As shown, the present invention provides a method for cleaning contaminants in a simulated wafer box, comprising:

[0112] Step 100: Determine the cleaning factors of the wafer cassette, including the area factors of each inner surface of the wafer cassette, edge factors, the relationship between the edge factors and the area factors, and solvent factors. The area factors include the planar area and shape of the six horizontal or overall horizontal surfaces of the wafer cassette, i.e., the area and shape of the solid portion of the wafer cassette's inner surface, including, for example, the area and shape of internal grooves on certain inner surfaces. The edge factors of a square-shaped wafer cassette include the curved depths and areas of the twelve edges. The relationship between the edge factors and the area factors includes the relationship between the two long jaws of the edge, such as the angle between the two long jaws and the relationship between the area and the edge. The solvent factors include the solvent volume, the concentration or ratio of the solvent's cleaning / extraction active ingredients, and the change in the concentration or ratio of the solvent's cleaning / extraction active ingredients during the cleaning process. The cleaning factors also include the wafer cassette volume. The primary purpose of this simulation is to replace static immersion with active cleaning. During the active cleaning process, the solvent volume and the wafer cassette volume have a certain proportional relationship.

[0113] Step 200: Input the cleaning elements to simulate a cleaning process so that the cleaning degree Qnr of n points on the inner surface of the wafer box is the same; the cleaning process includes the amount of solvent, the distance the solvent passes through the n points on the inner surface of the wafer box, the pressure of the solvent on the n points on the inner surface of the wafer box, the effective amount of the solvent cleaning component during the process, the number of cleaning times, and any relationship between any two or more of them; including that the cleaning process of the nth point after the rth cleaning satisfies the formula (1):

[0114] Qnr=∑qnr{a1*f(d,vnr),a2*s(vnr,r,r'),a3*e(d,r,r')}

[0115] Q1r=Q2r=Q3r=…Qnr (1)

[0116] Where r is the number of cleaning times, and r is a natural number greater than or equal to 2, and e(d, r, r’) < e(d, r - 1, r - 1’). Qnr is the cleaning amount of the solvent for the r-th cleaning of the n-th point, and Qnr is a functional relationship of the pressure f of the solvent for the r-th cleaning of the n-th point, the path s of the solvent passing through the n-th point, and the effective amount e of the cleaning component of the solvent for the r-th cleaning of the n-th point. f is a function of the solvent amount d and the velocity vnr at the r-th time (also considering the number of times of the redundant amount r’, not shown in the formula). s is a function of the velocity vnr at the r-th time (also considering the number of times of the redundant amount r’, not shown in the formula), the number of cleaning times r, and the number of times of the redundant amount r’. e is a function of the solvent amount d, the number of cleaning times r, and the number of times of the redundant amount r’; the redundant amount r’ can be an order of magnitude lower than the number of cleaning times r. For a single cleaning, r is counted as 1, and the redundant amount r’ is a positive number less than 1, such as 0.1; the redundant amount r’ can also be an order of magnitude higher than the number of cleaning times r. For a single cleaning, it is counted as 1, and the redundant amount r’ is a positive number greater than 1, such as 10 or 10.1; the redundant amount is crucial for adjusting the additional cleaning process due to the loss of the effective component of the solvent during the active cleaning process. For example, if there is no loss of the effective component of the solvent during the cleaning process and only the concentration of pollutants in the solvent increases without affecting the cleaning effect, then r’ is 0. If it affects the cleaning effect, then r’ is not 0. a1, a2, and a3 are respectively the weight relationships among the pressure f of the solvent for the r-th cleaning of the n-th point, the path s of the solvent passing through the n-th point, and the effective amount e of the cleaning component of the solvent for the r-th cleaning of the n-th point, and a1 + a2 + a3 = 1, or the value range of a1, a2, and a3 is 0.1 to 10. The relationship or value range among a1, a2, and a3 is for adjusting the overall contribution of f(d, vnr), s(vnr, r, r’), and e(d, r, r’) to Qnr or Qnr. For example, in the active cleaning process with uniform pressure, a1 = 0; when strictly controlling that the active solvent with a certain velocity passing through each point is the same (i.e., the product of the solvent velocity and time passing through each point is the same value), a2 = 0; when controlling and stabilizing the concentration (i.e., the proportion of the effective component) of the cleaning effective component in the solvent (or extraction liquid) in the wafer cassette in real time, a3 = 0. Among them, preferably, the number of cleaning times r (also considering the number of times of the redundant amount r’, not shown in the formula) at least includes the number of cycles of solvent cleaning. For an active cleaning process that mostly adopts a standard unified cycle as a whole, and then supplemented with a non-cycle process to clean the parts that do not reach the same cleaning degree during the cycle cleaning process, so as to make the cleaning degree Qnr of n points on the inner surface of the wafer cassette the same. In some cases, such as when the pollutant level on the top surface of the wafer cassette is less sensitive, the number of cleaning times r (also considering the number of times of the redundant amount r’, not shown in the formula) is the number of cycles, that is, specific cyclic active cleaning (such as rotating around the central axis of the top surface) is adopted to fully clean the four surfaces adjacent to the top surface, and specific cyclic active cleaning (such as uniform shaking can only barely cover the solvent or extraction liquid on the bottom surface) is adopted to fully clean the bottom surface opposite to the top surface.

[0117] The total cleaning volume, or cleaning degree, of the wafer cassette during the cleaning process is calculated by accumulating the cleaning volume at each cleaning step. It should be noted that qnr also includes the roughness, flatness, or friction coefficient of the nth point on the wafer's inner surface, used in conjunction with f(d, vnr). This means that the cleaning factor also includes the roughness, flatness, or friction coefficient of the wafer's inner surface. In high-precision industrial systems, the roughness, flatness, or friction coefficient of all points on the wafer cassette's inner surface is assumed to be the same, and f(d, vnr) is linearly related to the roughness, flatness, or friction coefficient. Therefore, the roughness, flatness, or friction coefficient of all points on the wafer cassette's inner surface can be ignored. However, when improving cleaning precision to the ppt level or even more extreme precision, the roughness, flatness, or friction coefficient of the nth point on the wafer's inner surface should be considered. By adjusting the number of vnr cycles (r), which also takes into account the number of redundancies (r'), not shown in the formula), direction, and size, and thus affecting f(d, vnr) and s(vnr, r r'), the same degree of cleaning can be achieved at n points on the inner surface of the wafer box. This allows for real-time and precise adjustment of the cleaning process, achieving uniform cleaning standards for all wafer boxes.

[0118] Step 300: If a condition is met, the simulation is stopped, wherein the condition at least includes a decrease in the cleaning volume increment.

[0119] The conditions include that qnr, qnr-1, and qnr-2 satisfy formula (2):

[0120] a5*qnr-2=qnr+a4*qnr-1 (2)

[0121] Where qnr is the cleaning amount of the solvent at the nth point after the rth cleaning, qnr-1 is the cleaning amount of the solvent at the nth point after the r-1th cleaning, and qnr-2 is the cleaning amount of the solvent at the nth point after the r-2th cleaning; a5 ranges from 0.01 to 0.2, and a4 ranges from 0.1 to 0.3; or, a4 and a5 are both positive numbers less than 1, satisfying a5 = 1 / 2 * a4 2, that is, the cleaning volume qnr increases non-uniformly with the previous two cleaning volumes qnr-1 and qnr-2. Conversely, the cleaning volumes qnr-2, qnr-1, and qnr decrease rapidly, and the cleaning volumes qnr-2 and qnr-1 differ by at least a factor of 2. Formula (2) under this condition simulates a cleaning process that includes the optimal solvent volume d, the minimum number of cleaning times r, and / or the shortest actual cleaning path. It should be noted that qnr-2, qnr-1, and qnr may be the cleaning amounts of continuous cleaning in the first state described below, or qnr-2, qnr-1, and qnr may be the cleaning amounts of continuous cleaning in the first state described below, or qnr-2, qnr-1, and qnr may be the cleaning amounts of continuous cleaning in the third state described below; if certain elements are the same in various states, such as the surface area and the solvent path, at least one of qnr-2, qnr-1, and qnr is the cleaning amount of continuous cleaning in different states, that is, the three states are executed crosswise, but the simulation is still ended using formula (2), which will not be repeated below.

[0122] The above is based on the cleaning process of n points in the wafer box, such as Figures 2 to 4 As shown, the applicant will now introduce a cleaning process based on the inner surface of the wafer box based on the cleaning process of n points in the above-mentioned wafer box, that is, the n points in the wafer box are evenly distributed to each surface in the wafer box, and the cleaning process is characterized by mainly cleaning each surface and its combination. Taking the cubic wafer box as an example, the cleaning process also includes a first state of cleaning the four surfaces of the wafer box and a second state of cleaning the remaining two surfaces of the wafer box.

[0123] like Figure 2 As shown, the first state is that the wafer box 1200 is vertically (i.e., the top surface of the wafer box 1200 is the first surface and is arranged horizontally) rotating around the axis (the axis of the device referred to in the whole text refers to the axis of the rotating shaft 1310) to clean the four surfaces (i.e., the four surfaces including the first surface, the opposite side of the first surface, i.e., the bottom surface, and the other two surfaces through which the solvent / extraction liquid passes), as shown. Figure 3 As shown, the second state is that the wafer box is horizontal (i.e., the top surface of the wafer box 1200 is the first surface and is vertically arranged) and rotates to clean the two surfaces (i.e., the two surfaces other than the above four surfaces); the cleaning process satisfies formula (3):

[0124] ak=Qi / Qii

[0125] Qi=q{a6*f(d,vi),a6*s(vi),a8*e(d,s)}

[0126] Qii=q{a6*f(d,vii),a7*s(vii),a8*e(d,s)} (3)

[0127] Among them, the value range of a is 0.1~10, k is the ratio of the total area of ​​the four surfaces cleaned in the first state to the total area of ​​the two surfaces cleaned in the second state, Qi is the cleaning degree in the first state, and Qii is the cleaning degree in the second state; the pressure f of the solvent on the inner surface of the wafer box is a function of the solvent amount d and the solvent speed v, the solvent distance s is a function of the solvent speed v, and the effective amount of cleaning component e is a function of the solvent amount d and the distance s; a6, a7, and a8 are the weighted relationships between the pressure f of the solvent on the inner surface of the wafer box in the first state or the second state, the distance s traveled by the solvent, and the effective amount of solvent cleaning component e, respectively, a6+a7+a8=1 or the value range of a6, a7, and a8 is 0.1~10.

[0128] It should be noted that, without replacing the solvent / extraction liquid, the solvent will inevitably partially clean at least one of the four surfaces of the first state due to the initialization of the first state process and when the first state is transformed into the second state. Therefore, the cleaning degree of the first state should include the cleaning of the last surface where the solvent stays and is transferred from there.

[0129] It should be further explained that in both the first and second states, the surfaces being cleaned by each other will be partially or even entirely cleaned. This mutual cleaning is not the primary cleaning in each state and can be adjusted using s(vi) and e(d,s); details are as follows. In the first state, the solvent will inevitably clean portions of the two surfaces being cleaned in the second state that are adjacent to the four surfaces being cleaned in the first state at the beginning, during (due to reasons such as excessive speed), or at the end. Similarly, in the second state (where two surfaces are cleaned separately and then swung or rocked around the axis in a small range, such as at an angle of less than 90 degrees), the solvent will inevitably clean the entire or portions of the four surfaces being cleaned in the first state that are adjacent to the two surfaces being cleaned in the second state at the beginning, during (due to reasons such as excessive speed or transition between two surfaces), and at the end. Discuss each case separately. For example, if the first state is executed before the second state, e(d,s(vi))≥e(d,s(vii)) exists, so s(vii)≥s(vi), that is, the second state has a longer cleaning time or distance, so that the overall cleaning degree of each cleaned surface is the same in the first and second states; for example, a 360-degree rotation around the axis in the second state will completely clean the two surfaces in the first state, so the cleaning of the two surfaces can be reduced in advance in the first state, such as the other two surfaces in the first state are shaken or swung around the axis in a small range, such as the shaking or oscillating angle is less than 90 degrees. If the second state is executed before the first state, e(d, s(vi))≤e(d, s(vii)), so s(vii)≤s(vi), that is, the first state has a longer cleaning time or distance, so that the first state and the second state have the same overall cleaning degree for each cleaned surface; if a 360-degree rotation around the axis is adopted in the second state to completely clean the two surfaces in the first state, then the cleaning of the two surfaces will be reduced in the first state subsequently, such as the other two surfaces are shaken or swung around the axis in a small range in the first state, such as the shaking or swung angle is less than 90 degrees, but since the two surfaces are cleaned in the second state and e(d, s(vi))≤e(d, s(vii)), the first state has s(vi)pre2sides for the cleaning of the other two surfaces much smaller than s(vi)post2sides for the other two surfaces, and the specific application will not be repeated here. By adopting appropriate f(d,vi), s(vi), e(d,s) and especially the solvent amount d, both the first state and the second state can fully clean all the edges, and the same degree of cleaning can be achieved for all the edges and all six surfaces.

[0130] In other embodiments, Figure 4As shown, based on formula (3), due to the failure to adopt appropriate (d, vi), s(vi), e(d, s) and especially the amount of solvent d, the cleaning process also includes a third state of cleaning a predetermined area including edges, and the first state and the second state are actually executed before the third state. Since all edges are cleaned in the first state and the second state, that is, e(d, s(viii))≤e(d, s(vi)) and e(d, s(viii))≤e(d, s(vii)). Even so, the duration or distance of the third state is less than the duration and distance of the second state or the first state, that is, s(viii)≤s(vi) and s(viii))≤s(vii).

[0131] It should be noted that if Figure 3 As shown, in the second state, the wafer box has only one initial rotation position, and the intermediate rotation position and the final rotation position are also the same as the initial rotation position; Figure 2 and Figure 4 As shown, in the first state and the third state, the wafer box has several initial rotation positions, several intermediate rotation positions and several final rotation positions respectively; therefore, the different initial, intermediate and final rotation positions of the first state and the second state can be accurately controlled in real time by formula (1) or formula (3) to ensure that the cleaning degree of each point on the inner surface of the wafer box is the same. The cleaning process including the minimum solvent amount d and the shortest actual length cleaning path is simulated and obtained. The cleaning path is selected from the initial rotation position, all the intermediate rotation positions and all the final rotation positions in the above-mentioned states and is composed of the paths between the positions. It should be noted that the cleaning path refers to the first state and the second state, which can be executed multiple times and in a cross-sequence order, such as executing the first state, the second state, the first state, the second state... in sequence. The relationship between the above various formulas should be changed in a cross-sequence order or in sequence to achieve the same cleaning degree of each point in the wafer box. Similarly, the first state, the second state and the third state can be executed multiple times, and the order can be crossed, such as executing the first state, the second state, the third state, the second state, the first state, the first state, the third state, the second state... in sequence. The relationship between the above formulas should be changed accordingly or in sequence in a cross-order to achieve the same cleaning degree at each point in the wafer box.

[0132] In this embodiment, in the first state, the second state or the third state, a point on the wafer box body is used as the driving point for rotation, that is, the rotating shaft 1310 or a point on the wafer box body directly connected to the connecting shaft 1313. In this case, some simulated cleaning paths are more complicated and speed changes are likely to damage the wafer box shell. Therefore, in another embodiment, the wafer box 1200 rotates in a container (not shown); or, the wafer box 1200 is connected and rotated through its own components.

[0133] The method for cleaning contaminants in a simulated wafer box proposed by the present invention has beneficial effects: a method for extracting / cleaning contaminants in a wafer box is obtained, which includes a cleaning process that uses the least amount of solvent, the least time, or the shortest cleaning process. The amount of solvent / extraction liquid used is low, which saves costs, and can realize real-time and precise adjustment of the cleaning process to achieve uniform standard cleaning of contaminants in all wafer boxes.

[0134] A method for extracting contaminants from a wafer box based on the above simulation is also provided. Figures 1 to 4 、 Figure 6a to Figure 6f Shown, including:

[0135] Step S1: Adding solvent into the wafer cassette 1200. The optimal solvent amount dex obtained by the above simulation is still denoted as d for simplicity. The volume of the solvent amount d should not exceed 50% of the volume of the wafer cassette 1200, and the solvent can completely immerse the largest surface of the wafer cassette 1200. The volume of the solvent amount d is 5-20% of the volume of the wafer cassette 1200.

[0136] Step S2: Figure 2 As shown, the wafer box 1200 is adjusted to a first state, with the first surface of the wafer box 1200 being horizontal and facing upward. Preferably, the first surface is the top surface of the wafer box 1200. The wafer box 1200 rotates around the axis to clean four surfaces including the first surface.

[0137] Step S3: Figure 3 As shown, the wafer box 1200 is adjusted to the second state to make the first surface vertical, and rotates around the axis to clean the remaining two surfaces:

[0138] like Figure 4 As shown, the method further includes step S4: adjusting the state to a third state, tilting the first surface, and rotating the wafer box around the axis to clean a predetermined area;

[0139] The method may further include step S5: removing the solvent, analyzing and calculating the level of pollutant content;

[0140] The first state and the third state have a plurality of initial rotation positions, the third state has a plurality of intermediate rotation positions, and the first state, the second state, and the third state enable n points on the inner surface of the wafer box to be cleaned to the same degree;

[0141] The cleaning process includes steps S2, S3, and S4, each of which is executed once, and the order of execution is any one of the permutations and combinations of S2, S3, and S4, or the cleaning process includes steps S2, S3, and S4, each of which is executed multiple times. Figure 3 As shown, in the second state, the wafer box has only one initial rotation position, and the intermediate rotation position and the final rotation position are also the same as the initial rotation position; Figure 2 and Figure 4 As shown, in the first state and the third state, the wafer box has several initial rotation positions, several intermediate rotation positions and final rotation positions respectively; therefore, the different initial, intermediate and final rotation positions of the first state and the second state can be accurately controlled in real time by formula (1) or formula (3) to perform simulation to obtain a cleaning process, which includes a cleaning process with a minimum solvent amount d and a cleaning path with the shortest actual length. The cleaning path is simulated and selected from the initial rotation position, all the intermediate rotation positions and all the final rotation positions in the above-mentioned states and is composed of paths between the positions, so that the cleaning degree of each point on the inner surface of the wafer box is the same.

[0142] The cleaning process of the nth point on the inner surface of the wafer box 1200 after the rth cleaning makes the first state and the second state satisfy the formula (1):

[0143] Qnr=∑qnr{a1*f(d,vnr),a2*s(vnr,r,r'),a3*e(d,r,r')}

[0144] Q1r=Q2r=Q3r=…Qnr (1)

[0145] Among them, r is the number of cleaning times, r is a natural number greater than or equal to 2, and e(d, r, r’) < e(d, r - 1, r - 1’). qnr is the cleaning amount of the solvent for the r-th cleaning of the n-th point. qnr is a functional relationship of the pressure f of the solvent for the r-th cleaning of the n-th point, the path s of the solvent passing through the n-th point, and the effective amount e of the cleaning component of the solvent for the r-th cleaning of the n-th point. f is a function of the solvent amount d and the velocity vnr at the r-th time (also considering the number of times of the redundancy amount r’, not shown in the formula). s is a function of the velocity vnr at the r-th time (also considering the number of times of the redundancy amount r’, not shown in the formula), the number of cleaning times r, and the redundancy amount r’ of the number of times. e is a function of the solvent amount d, the number of cleaning times r, and the redundancy amount r’ of the number of times; the redundancy amount r’ can be of the order of magnitude lower than the number of cleaning times r. For a single cleaning, r is counted as 1, and the redundancy amount r’ is a positive number less than 1, such as 0.1; the redundancy amount r’ can also be of the order of magnitude higher than the number of cleaning times r. For a single cleaning, it is counted as 1, and the redundancy amount r’ is a positive number greater than 1, such as 10 or 10.1; the redundancy amount is crucial for adjusting the additional cleaning process due to the loss of the effective component of the solvent during the active cleaning process. For example, if there is no loss of the effective component of the solvent during the cleaning process and only the concentration of pollutants in the solvent increases and does not affect the cleaning effect, then r’ is 0. If it affects the cleaning effect, then r’ is not 0. a1, a2, and a3 are respectively the weight relationships among the pressure f of the solvent for the r-th cleaning of the n-th point, the path s of the solvent passing through the n-th point, and the effective amount e of the cleaning component of the solvent for the r-th cleaning of the n-th point. a1 + a2 + a3 = 1, or the value range of a1, a2, and a3 is 0.1 to 10. The relationship or value range among a1, a2, and a3 is to adjust the overall contribution of f(d, vnr), s(vnr, r, r’), and e(d, r, r’) to qnr or Qnr. For example, in the active cleaning process with uniform pressure, a1 = 0; when strictly controlling that the active solvent with a certain velocity passing through each point is the same (that is, the solvent velocity * time passing through each point is the same value), a2 = 0; when controlling and stabilizing the concentration (i.e., the proportion of the effective component) of the cleaning effective component in the solvent (or extraction liquid) in the wafer cassette in real time, a3 = 0. Among them, preferably, the number of cleaning times r (also considering the number of times of the redundancy amount r’, not shown in the formula) at least includes the number of cycles of solvent cleaning. For an active cleaning process that mostly adopts a standard unified cycle as a whole, and then supplemented with a non-cycle process to clean the parts that do not reach the same cleaning degree during the cycle cleaning process, so as to make the cleaning degree Qnr of n points on the inner surface of the wafer cassette the same. In some cases, such as when the pollutant level on the top surface of the wafer cassette is less sensitive, the number of cleaning times r (also considering the number of times of the redundancy amount r’, not shown in the formula) is the number of cycles, that is, a specific cyclic active cleaning (such as rotating around the central axis of the top surface) is adopted to fully clean the four surfaces adjacent to the top surface, and a specific cyclic active cleaning (such as uniformly shaking can only barely cover the solvent or extraction liquid on the bottom surface) is adopted to fully clean the bottom surface opposite to the top surface.As described in the simulation process, if it is not possible to adopt a cleaning process suitable for f(d,vi), s(vi), e(d,s) and especially the solvent amount d according to formula (3) or without the need for the third state (i.e., without the solvent amount d in the third state). not3rdstatus and cleaning paths not3rdstatus ), then, the cleaning process of the nth point on the inner surface of the wafer box 1200 after the rth cleaning is that the above-mentioned first state, second state and third state satisfy formula (1) and formula (2), and the application will not repeat them.

[0146] According to the simulation, the cleaning is completed when qnr, qnr-1, and qnr-2 of n points on the inner surface of the wafer box 1200 satisfy formula (2):

[0147] a5*qnr-2=qnr+a4*qnr-1 (2)

[0148] Where qnr is the cleaning amount of the solvent at the nth point after the rth cleaning, qnr-1 is the cleaning amount of the solvent at the nth point after the r-1th cleaning, and qnr-2 is the cleaning amount of the solvent at the nth point after the r-2th cleaning; a5 ranges from 0.01 to 0.2, and a4 ranges from 0.1 to 0.3; or, a4 and a5 are both positive numbers less than 1, satisfying a5 = 1 / 2 * a4 2 , that is, the cleaning volume qnr and the previous two cleaning volumes qnr-1 and qnr-2 increase non-uniformly in sequence. On the contrary, the cleaning volumes qnr-2, qnr-1, and qnr decrease rapidly in sequence, and the cleaning volumes qnr-2 and qnr-1 differ by at least 2 times. The simulated cleaning process including the optimal solvent volume d (or dex above), the minimum number of cleaning times r, and / or the shortest actual length of the cleaning path satisfies formulas (1) and (2).

[0149] In embodiments where a third state of cleaning is desired, such as Figure 4 As shown, the predetermined area at least includes edge portions such as L1 and L2, and / or a portion of the surface formed by the edge portions.

[0150] In this embodiment, if Figure 2 As shown, in step S1, the wafer box 1200 is horizontally facing the first surface, i.e., the top surface, and solvent is added into the wafer box, and the amount of solvent at least immerses the bottom surface opposite to the first surface, or the amount of solvent at least immerses the edge of the bottom surface opposite to the first surface.

[0151] like Figure 2 and Figure 3As shown, the duration of the first state and the second state is related to the area ratio of the cleaning. The first state is that the wafer box rotates vertically to clean the four surfaces, and the second state is that the wafer box rotates horizontally to clean the two surfaces; the cleaning process satisfies formula (3):

[0152] ak=Qi / Qii

[0153] Qi=q{a6*f(d,vi),a6*s(vi),a8*e(d,s)}

[0154] Qii=q{a6*f(d,vii),a7*s(vii),a8*e(d,s)} (3)

[0155] Among them, the value range of a is 0.1~10, k is the ratio of the total area of ​​the four surfaces cleaned in the first state to the total area of ​​the two surfaces cleaned in the second state, Qi is the cleaning degree in the first state, and Qii is the cleaning degree in the second state; the pressure f of the solvent on the opposite side is a function of the solvent amount d and the solvent speed v, the solvent distance s is a function of the solvent speed v, and the effective amount of cleaning component e is a function of the solvent amount d and the distance s; a6, a7, and a8 are the weighted relationships between the pressure f of the solvent on the opposite side in the first state or the second state, the distance s traveled by the solvent, and the effective amount of solvent cleaning component e, respectively, a6+a7+a8=1 or the value range of a6, a7, and a8 is 0.1~10.

[0156] It should be noted that, without replacing the solvent / extraction liquid, the solvent will inevitably partially clean at least one of the four surfaces of the first state due to the initialization of the first state process and when the first state is transformed into the second state. Therefore, the cleaning degree of the first state should include the cleaning of the last surface where the solvent stays and is transferred from there.

[0157] It should be further explained that in both the first and second states, the surfaces cleaned by each other will be partially or even entirely cleaned. This mutual cleaning is not the primary cleaning in each state and can be adjusted using s(vi) and e(d,s); details are as follows. In the first state, the solvent will inevitably clean portions of the two surfaces cleaned in the first state that are adjacent to the four surfaces cleaned in the first state at the beginning, during (due to reasons such as excessive speed), or at the end. Similarly, in the second state (where the two surfaces are cleaned separately and then swung or rocked around the axis in a small range, such as at an angle of less than 90 degrees), the solvent will inevitably clean the entire or portions of the four surfaces cleaned in the first state that are adjacent to the two surfaces cleaned in the second state at the beginning, during (due to reasons such as excessive speed or transition between the two surfaces), and at the end. Discuss each case separately. For example, if the first state is executed before the second state, that is, step S2 is executed before step S3, there is e(d, s(vi))≥e(d, s(vii)), so s(vii)≥s(vi), that is, the second state has a longer cleaning time or distance, so that the first state and the second state have the same overall cleaning degree for each cleaned surface; if a 360-degree rotation around the axis in the second state will completely clean the two surfaces in the first state, then the cleaning of the two surfaces can be reduced in advance in the first state, such as the other two surfaces in the first state are shaken or swung around the axis in a small range, such as the shaking or swung angle is less than 90 degrees. If the second state is executed before the first state, that is, S3 is executed before step S2, e(d, s(vi))≤e(d, s(vii)), so s(vii)≤s(vi), that is, the first state has a longer cleaning time or distance, so that the first state and the second state have the same overall cleaning degree for each cleaned surface; if a 360-degree rotation around the axis is adopted in the second state to completely clean the two surfaces in the first state, then the cleaning of the two surfaces will be reduced in the first state subsequently, such as in the first state, the other two surfaces are shaken or swung around the axis in a small range, such as the shaking or swung angle is less than 90 degrees, but since the two surfaces are cleaned in the second state and e(d, s(vi))≤e(d, s(vii)), the first state has s(vi)pre2sides for the cleaning of the other two surfaces much smaller than s(vi)post2sides for the other two surfaces, and the specific application will not be repeated here. By adopting appropriate f(d,vi), s(vi), e(d,s) and especially the solvent amount d, both the first state and the second state can fully clean all the edges, and the same degree of cleaning can be achieved for all the edges and all six surfaces.

[0158] In other embodiments, Figure 4As shown, formula (3) does not take appropriate (d, vi), s(vi), e(d, s) and especially the amount of solvent d, the cleaning process also includes a third state of cleaning a predetermined area including the edge, and the first state and the second state are actually executed before the third state. Since all the edges are cleaned in the first state and the second state, that is, e(d, s(viii))≤e(d, s(vi)) and e(d, s(viii))≤e(d, s(vii)). Even so, the duration or distance of the third state is less than the duration and distance of the second state or the first state, that is, s(viii)≤s(vi) and s(viii))≤s(vii).

[0159] It should be noted that if Figure 3 As shown, in the second state, the wafer box has only one initial rotation position, and the intermediate rotation position and the final rotation position are also the same as the initial rotation position; Figure 2 and Figure 4 As shown, in the first state and the third state, the wafer box has several initial rotation positions, several intermediate rotation positions and final rotation positions respectively; therefore, the different initial, intermediate and final rotation positions of the first state and the second state can be accurately controlled in real time by a program or formula (1) or formula (3) to ensure that the cleaning degree of each point on the inner surface of the wafer box is the same. The cleaning process obtained by simulation, including the minimum solvent amount d and the shortest actual length of the cleaning path, satisfies formulas (1) and (2) to perform cleaning. The cleaning path is selected from the initial rotation position, all the intermediate rotation positions and all the final rotation positions in the above-mentioned states and is composed of the paths between the positions. It should be noted that the cleaning path refers to the first state and the second state, which can be executed multiple times and can be cross-sequenced, such as executing the first state, the second state, the first state, the second state... in sequence. The relationship between the above various formulas should be cross-sequenced and changed accordingly or in sequence to achieve the same cleaning degree of each point in the wafer box. Similarly, the first state, the second state and the third state can be executed multiple times, and the order can be crossed, such as executing the first state, the second state, the third state, the second state, the first state, the first state, the third state, the second state... in sequence. The relationship between the above formulas should be changed accordingly or in sequence in a cross-order to achieve the same cleaning degree at each point in the wafer box.

[0160] When the cleaning / extraction active ingredients in the solvent only promote the dissolution of pollutants, that is, the concentration of pollutants increases while the active ingredients of the solvent do not decrease, then a6=a8=0, and the distances traveled by the solvent in the first state and the second state are equal, so that the cleaning degrees of n points on the inner surface of the wafer box are the same. The cleaning degrees Qi in the first state and Qii in the second state are equal, which can be expressed as:

[0161] Qi=s(vi)=∫vitidt,

[0162] Qii=s(vii)=∫viitiidt;

[0163] Among them, s(vi) and s(vii) are the distances traveled by the solvent in the first state and the second state respectively, vi and vii are the speeds of the solvent in the first state and the second state respectively, and ti and tii are the duration of the first state and the second state respectively.

[0164] The present invention provides a method for extracting pollutants in a wafer box, which uses a low amount of solvent / extraction liquid, saves costs, and can realize real-time and precise adjustment of the cleaning process to achieve uniform standard cleaning of all wafer boxes.

[0165] In order to realize the above extraction and cleaning method, the applicant also provides a device for extracting contaminants from wafer boxes, such as Figures 2 to 4 、 Figure 6a to Figure 6f As shown, it includes a controller (not shown), a power device 1000 controlled by the controller, a rotating shaft 1310 and a connecting shaft 1313 connected to the power device 1000; it is characterized in that it also includes,

[0166] a universal joint 1320 for the connecting shaft 1313 to slide inside so as to control the connecting shaft 1313 to freely switch directions in a hemispherical direction;

[0167] The connecting shaft 1313 is connected to the wafer box 1200, and the rotating shaft 1310 rotates synchronously or asynchronously to drive the universal joint 1320 to rotate and drive the wafer box 1200 to rotate around the axis of the rotating shaft 1310. The universal joint 1320 includes: a vertical slot 1321 to control the sliding of the connecting shaft 1313 in the vertical direction to achieve the first state of rotating the wafer box 1200; a horizontal slot 1323 to control the sliding of the connecting shaft 1313 in the horizontal direction to achieve the second state of rotating the wafer box 1200; and an inclined slot 1322 to control the sliding of the connecting shaft 1313 in the inclined direction to achieve the third state of rotating the wafer box 1200, wherein the vertical slot 1321 is a single hole, the horizontal slot 1323 is a single hole at the center, and the inclined slot 1322 is a single hole. There are 2 to 10 inclined grooves 322, and the inclined grooves 1322 are evenly distributed to evenly adjust the inclination angle of the connecting shaft 1313 when it slides in the adjacent inclined grooves 1322. For example, there are 4 inclined grooves 1322, and the angles θ between the connecting shaft 1313 and the axis of the rotating shaft 1310 that are sequentially drawn into the inclined grooves 1322 from the periphery to the center from the vertical groove 1321 are 90 degrees, 72 degrees, 54 degrees, 36 degrees, and 18 degrees, respectively. The number of inclined grooves 1322 can also be set in a way that the acute angle of the diagonal of the wafer box 1200 is evenly divided by 90 degrees. The applicant will not go into details here.

[0168] like Figure 2 As shown, the first state is that the wafer box 1200 is horizontal with its first surface, i.e., the top surface, facing upward, and the wafer box 1200 rotates around the axis of the rotation axis 1310 to clean four surfaces including the first surface;

[0169] like Figure 3 As shown, the second state is to make the first surface vertical, and the wafer box 1200 rotates around the axis of the rotation axis 1310 to clean the remaining two surfaces;

[0170] like Figure 4 As shown, the third state is to tilt the first surface and rotate the wafer box 1200 around the axis of the rotation shaft 1310 to clean a predetermined area;

[0171] like Figure 6a and Figure 6cAs shown, in the first state, the wafer box 1200 has several initial rotation positions (i.e., the position of the connecting shaft 1313) in the vertical slot 1321, and the initial rotation position can be an intermediate rotation position and an end rotation position during the first state, that is, the first state has multiple intermediate rotation positions and an end rotation position. In the third state, the wafer box 1200 has several initial rotation positions (such as the position of the positioning structure 1325 that matches the shape of the connecting shaft 1313) in the inclined slots 1322, and the initial rotation position can be an intermediate rotation position and an end rotation position during the third state, that is, the third state has multiple intermediate rotation positions and an end rotation position. In the second state, the wafer box 1200 has only one initial rotation position (i.e., the position of the connecting shaft 1313) in the horizontal slot 1323. Similarly, in the second state, there can be only one intermediate rotation position and an end rotation position 1323. Therefore, through the different initial, intermediate, and end rotation positions in the first and second states, it can be accurately controlled in real time by formula (1) or formula (3) to ensure that the cleaning degree of n points on the inner surface of the wafer box is the same. The cleaning process is defined as the cleaning path that includes the minimum solvent volume d and the shortest actual length. This cleaning path is composed of at least one selected from each of the initial rotational position, all of the intermediate rotational positions, and all of the final rotational positions in the aforementioned states, and is formed by the paths between these positions. It should be noted that the cleaning path refers to the first state and the second state, which can be executed multiple times and in a cross-sequence order, such as sequentially executing the first state, the second state, the first state, the second state, etc. The relationships between the above formulas should correspond to or change sequentially in a cross-sequence order to achieve the same cleaning level at each point in the wafer cassette. Similarly, the first state, the second state, and the third state can be executed multiple times and in a cross-sequence order, such as sequentially executing the first state, the second state, the third state, the second state, the first state, the first state, the third state, the second state, etc. The relationships between the above formulas should correspond to or change sequentially in a cross-sequence order to achieve the same cleaning level at n points in the wafer cassette.

[0172] like Figure 6b and Figure 6c As shown, the universal guide 1320 is semicircular or sheet-shaped. The universal guide 1320 further includes a plurality of connecting slots 1324 to connect the vertical slot 1321 , the horizontal slot 1323 and the inclined slot 1322 .

[0173] like Figure 6c As shown, the vertical slot 1321 , the horizontal slot 1323 or the inclined slot 1322 includes a positioning structure 1325 that cooperates with the connecting shaft 1313 to fix the direction.

[0174] like Figure 6d to Figure 6fAs shown, the circular opening positioning structure 1325 includes a positioning component 13251 located at the bottom of the positioning structure 1325, and a positioning accessory 13131 is provided on the portion of the connecting shaft 1313 corresponding to the positioning component 13251. Preferably, the positioning component 13251 is a transverse elastic spring structure, and the positioning accessory 13131 is a groove structure that cooperates with the spring structure and has a portion smaller than the transverse diameter of the spring structure in the loose state. When the connecting shaft 1313 is connected to the wafer box 1200 and moves in a circular motion around the axis of the rotating shaft 1310 or at a certain speed and the centrifugal force is provided by the positioning structure 1325, the wafer box 1200 can be The retaining spring structure is squeezed into the groove structure to achieve positioning; when adjusting the initial, intermediate and final rotation positions of the connecting shaft 1313 in the first state, the second state and the third state according to the above, when the wafer box 1200 is at the top position of the circumference, the speed can be reduced and the weight of the wafer box 1200 drives the connecting shaft 1313 along the opposite direction of x to make the retaining spring structure laterally compressed and disengaged from the groove structure so that the wafer box re-enters the vertical groove 1321, the horizontal groove 1323 or the inclined groove 1322 and moves along the positive or negative direction of y, and continues to be cleaned according to the cleaning path in the above-mentioned extraction method. The applicant will not go into details here.

[0175] In one embodiment, the other end of the connecting shaft 1313 connected to the wafer box 1200 is fixed to the center position of the universal joint 1320, and only the speed of the wafer box 1200 driven by the rotating shaft 1310, the centrifugal force provided to the wafer box by the universal joint 1320, and the weight of the wafer box 1200 and the connecting shaft 1313 itself are used to adjust the initial, middle and final rotation positions of the wafer box 1200 in the above-mentioned first state, second state and third state to execute the cleaning path in the above-mentioned extraction method.

[0176] In another embodiment, Figure 6a and Figure 6bAs shown, the rotating part 1300 includes a steering shaft 1311 and a steering device 1312. The rotating shaft 1310 is a hollow structure to accommodate the steering shaft 1311 and the steering device 1312, and the three are coaxial. The steering shaft 1311 is fixedly connected to the steering device 1312. The steering device 1312 is rotatably connected to the connecting shaft 1313 and can allow the connecting shaft 1313 to freely change direction along the groove on the universal joint 1320 in the hemispherical space. The power device 1000 provides a pulling force, a thrust or a rotational force as shown in the figure to the control shaft 1311. When the power device 1000 provides a pulling force to the left, the control shaft 1311 will drive the connecting shaft 1313 to slide from the vertical slot 1321 to the inclined slot 1322 and finally to the horizontal slot 1323. When the power device 1000 provides a thrust to the right, the control shaft 1311 will drive the connecting shaft 1313 to move from the position in the universal joint 1320 when the thrust is initiated to the outer inclined slot 1322, the vertical slot 1321, until the control shaft 1313 is in the horizontal slot 1323. When the universal joint 1323 reaches the center of the universal joint 1320, the connecting shaft returns to the vertical groove 1321. At this time, the power device 1000 can provide a rotational force to the control shaft 1311 to drive the connecting shaft 1313 to rotate in the vertical groove 1321. Since the wafer box 1200 and the connecting shaft 1313 have their own weight, the rotational force provided should be a force to assist the rotation. The weight and the speed provided by the rotating shaft 1310 to the connecting shaft 1313 and even the wafer box 1200 through the universal joint 1320 should be used to execute the above-mentioned cleaning path. It should be noted that when the connecting shaft 1313 slides out of the positioning structure 1325, the control shaft 1311 can provide some rotational force to supplement or assist the rotational force provided by the rotating shaft 1310, so as to avoid the connection shaft 1313 failing to clean the relevant positions in the above-mentioned cleaning path due to high speed. The applicant will not elaborate on this here.

[0177] It is particularly important to note that the rotating shaft 1310 can only serve as a fixed component for fixing the universal joint 1320 and as a shell for accommodating the control shaft 1311 and the control device 1312, and does not provide rotational force or turning force to the connecting shaft 1313 or even the wafer box 1200 through the universal joint 1320 to execute the above-mentioned cleaning path. Instead, the controller (not shown) only controls the control shaft 1311 to provide rotational force and turning force to the connecting shaft 1313 to execute the above-mentioned cleaning path. During this process, the rotating shaft 1310 and the universal joint 1320 can be driven by the connecting shaft 1313 to rotate around the axis, or they may not rotate.

[0178] Preferably, the predetermined area at least includes an edge portion, and / or a portion of both sides of the edge portion.

[0179] like Figure 2 and Figure 3As shown, the duration of the first state and the second state is related to the area ratio of the cleaning. The first state is that the wafer box rotates vertically to clean the four surfaces, and the second state is that the wafer box rotates horizontally to clean the two surfaces; the controller uses a cleaning process that satisfies formula (3), that is, the controller uses a program including formula (3) to make the relationship between the cleaning degree of the first state and the cleaning degree of the second state related to the area ratio of the cleaning:

[0180] ak=Qi / Qii

[0181] Qi=q{a6*f(d,vi),a6*s(vi),a8*e(d,s)}

[0182] Qii=q{a6*f(d,vii),a7*s(vii),a8*e(d,s)} (3)

[0183] Among them, the value range of a is 0.1~10, k is the ratio of the total area of ​​the four surfaces cleaned in the first state to the total area of ​​the two surfaces cleaned in the second state, Qi is the cleaning degree in the first state, and Qii is the cleaning degree in the second state; the pressure f of the solvent on the inner surface of the wafer box is a function of the solvent amount d and the solvent speed v, the solvent distance s is a function of the solvent speed v, and the effective amount of cleaning component e is a function of the solvent amount d and the distance s; a6, a7, and a8 are the weighted relationships between the pressure f of the solvent on the inner surface of the wafer box in the first state or the second state, the distance s traveled by the solvent, and the effective amount of solvent cleaning component e, respectively, a6+a7+a8=1 or the value range of a6, a7, and a8 is 0.1~10.

[0184] It should be noted that, without replacing the solvent / extraction liquid, the solvent will inevitably partially clean at least one of the four surfaces of the first state due to the initialization of the first state process and when the first state is transformed into the second state. Therefore, the cleaning degree of the first state should include the cleaning of the last surface where the solvent stays and is transferred from there.

[0185] It should be further explained that in both the first and second states, the surfaces cleaned by each other will be partially or even entirely cleaned. This mutual cleaning is not the primary cleaning in each state and can be adjusted using s(vi) and e(d,s); details are as follows. In the first state, the solvent will inevitably clean portions of the two surfaces cleaned in the first state that are adjacent to the four surfaces cleaned in the first state at the beginning, during (due to reasons such as excessive speed), or at the end. Similarly, in the second state (where the two surfaces are cleaned separately and then swung or rocked around the axis in a small range, such as at an angle of less than 90 degrees), the solvent will inevitably clean the entire or portions of the four surfaces cleaned in the first state that are adjacent to the two surfaces cleaned in the second state at the beginning, during (due to reasons such as excessive speed or transition between the two surfaces), and at the end. Discuss each case separately. For example, if the first state is executed before the second state, that is, step S2 is executed before step S3, there is e(d, s(vi))≥e(d, s(vii)), so s(vii)≥s(vi), that is, the second state has a longer cleaning time or distance, so that the first state and the second state have the same overall cleaning degree for each cleaned surface; if a 360-degree rotation around the axis in the second state will completely clean the two surfaces in the first state, then the cleaning of the two surfaces can be reduced in advance in the first state, such as the other two surfaces in the first state are shaken or swung around the axis in a small range, such as the shaking or swung angle is less than 90 degrees. If the second state is executed before the first state, that is, S3 is executed before step S2, e(d, s(vi))≤e(d, s(vii)), so s(vii)≤s(vi), that is, the first state has a longer cleaning time or distance, so that the first state and the second state have the same overall cleaning degree for each cleaned surface; if a 360-degree rotation around the axis is adopted in the second state to completely clean the two surfaces in the first state, then the cleaning of the two surfaces will be reduced in the first state subsequently, such as in the first state, the other two surfaces are shaken or swung around the axis in a small range, such as the shaking or swung angle is less than 90 degrees, but since the two surfaces are cleaned in the second state and e(d, s(vi))≤e(d, s(vii)), the first state has s(vi)pre2sides for the cleaning of the other two surfaces much smaller than s(vi)post2sides for the other two surfaces, and the specific application will not be repeated here. By adopting appropriate f(d,vi), s(vi), e(d,s) and especially the solvent amount d, both the first state and the second state can fully clean all the edges, and the same degree of cleaning can be achieved for all the edges and all six surfaces.

[0186] In other embodiments, Figure 4As shown, the controller uses a program based on formula (3). Since appropriate (d, vi), s(vi), e(d, s) and especially the amount of solvent d are not adopted, the controller controls the cleaning process to also include a third state of cleaning a predetermined area including the edge, and the first state and the second state are actually executed before the third state. Since all the edges are cleaned in the first state and the second state, that is, e(d, s(viii))≤e(d, s(vi)) and e(d, s(viii))≤e(d, s(vii)). Even so, the duration or distance of the third state is less than the duration and distance of the second state or the first state, that is, s(viii)≤s(vi) and s(viii))≤s(vii).

[0187] When the cleaning / extraction active ingredients in the solvent only promote the dissolution of pollutants, that is, the concentration of pollutants increases while the active ingredients of the solvent do not decrease, then a6=a8=0, and the distances traveled by the solvent in the first state and the second state are equal, so that the cleaning degrees of n points on the inner surface of the wafer box are the same. The cleaning degrees Qi in the first state and Qii in the second state are equal, which can be expressed as:

[0188] Qi=s(vi)=∫vitidt,

[0189] Qii=s(vii)=∫viitiidt;

[0190] Among them, s(vi) and s(vii) are the distances traveled by the solvent in the first state and the second state respectively, vi and vii are the speeds of the solvent in the first state and the second state respectively, and ti and tii are the duration of the first state and the second state respectively.

[0191] The controller controls so that the first state and the second state in the cleaning process after the nth point on the inner surface of the wafer box 1200 is cleaned for the rth time satisfy the formula (1):

[0192] Qnr=∑qnr{a1*f(d,vnr),a2*s(vnr,r,r'),a3*e(d,r,r')}

[0193] Q1r=Q2r=Q3r=…Qnr (1)

[0194] Among them, r is the number of cleaning times, r is a natural number greater than or equal to 2, and e(d, r, r’) < e(d, r - 1, r - 1’). qnr is the cleaning amount of the solvent for the r-th cleaning of the n-th point, and qnr is a functional relationship of the pressure f of the solvent for the r-th cleaning of the n-th point, the path s of the solvent passing through the n-th point, and the effective amount e of the cleaning component of the solvent for the r-th cleaning of the n-th point. f is a function of the solvent amount d and the velocity vnr at the r-th time (also considering the number of times of the redundancy amount r’, not shown in the formula). s is a function of the velocity vnr at the r-th time (also considering the number of times of the redundancy amount r’, not shown in the formula), the cleaning times r, and the redundancy amount r’ of the times. e is a function of the solvent amount d, the cleaning times r, and the redundancy amount r’ of the times; the redundancy amount r’ can be an order of magnitude lower than the cleaning times r, with a single cleaning r counted as 1, and the redundancy amount r’ being a positive number less than 1, such as 0.1; the redundancy amount r’ can also be an order of magnitude higher than the cleaning times r, with a single cleaning counted as 1, and the redundancy amount r’ being a positive number greater than 1, such as 10 or 10.1; the redundancy amount is crucial for adjusting the additional cleaning process due to the loss of the effective component of the solvent during the active cleaning process. For example, if there is no loss of the effective component of the solvent during the cleaning process and only the concentration of pollutants in the solvent increases without affecting the cleaning effect, then r’ is 0. If it affects the cleaning effect, then r’ is not 0. a1, a2, and a3 are respectively the weight relationships among the pressure f of the solvent for the r-th cleaning of the n-th point, the path s of the solvent passing through the n-th point, and the effective amount e of the cleaning component of the solvent for the r-th cleaning of the n-th point, and a1 + a2 + a3 = 1 or the value range of a1, a2, and a3 is 0.1 to 10. The relationship or value range among a1, a2, and a3 is to adjust the overall contribution of f(d, vnr), s(vnr, r, r’), and e(d, r, r’) to qnr or Qnr. For example, in the active cleaning process with uniform pressure, a1 = 0; when strictly controlling that the solvents passing through each point with a certain velocity are the same (i.e., the product of the solvent velocity and time passing through each point is the same value), a2 = 0; when controlling and stabilizing the concentration (i.e., the proportion of the effective component) of the cleaning effective component in the solvent (or extraction liquid) in the wafer cassette in real time, a3 = 0. Among them, preferably, the cleaning times r (also considering the number of times of the redundancy amount r’, not shown in the formula) at least include the number of cycles of solvent cleaning. For an active cleaning process that mostly adopts a standard unified cycle as a whole, a non-cycle process is used to supplement the parts that do not reach the same cleaning degree during the cycle cleaning process, so as to make the cleaning degree Qnr of n points on the inner surface of the wafer cassette the same. In some cases, such as when the pollutant level on the top surface of the wafer cassette is less sensitive, the cleaning times r (also considering the number of times of the redundancy amount r’, not shown in the formula) is the number of cycles, that is, specific cyclic active cleaning (such as rotating around the central axis of the top surface) is adopted to fully clean the four surfaces adjacent to the top surface, and specific cyclic active cleaning (such as uniformly shaking, which can only barely cover the solvent or extraction liquid on the bottom surface) is adopted to fully clean the bottom surface opposite to the top surface.As described in the simulation process, if it is not possible to adopt a cleaning process suitable for f(d,vi), s(vi), e(d,s) and especially the solvent amount d according to formula (3) or without the need for the third state (i.e., without the solvent amount d in the third state). not3rdstatus and cleaning paths not3rdstatus ), then, the cleaning process of the nth point on the inner surface of the wafer box 1200 after the rth cleaning is that the above-mentioned first state, second state and third state satisfy formula (1) and formula (2), and the application will not be repeated.

[0195] When qnr, qnr-1, and qnr-2 at n points on the inner surface of the wafer box 1200 satisfy formula (2), cleaning is completed:

[0196] a5*qnr-2=qnr+a4*qnr-1 (2)

[0197] Where qnr is the cleaning amount of the solvent at the nth point after the rth cleaning, qnr-1 is the cleaning amount of the solvent at the nth point after the r-1th cleaning, and qnr-2 is the cleaning amount of the solvent at the nth point after the r-2th cleaning; a5 ranges from 0.01 to 0.2, and a4 ranges from 0.1 to 0.3; or, a4 and a5 are both positive numbers less than 1, satisfying a5 = 1 / 2 * a4 2 , that is, the cleaning volume qnr and the previous two cleaning volumes qnr-1 and qnr-2 increase non-uniformly in sequence. On the contrary, the cleaning volumes qnr-2, qnr-1, and qnr decrease rapidly in sequence, and the cleaning volumes qnr-2 and qnr-1 differ by at least 2 times. The cleaning process obtained by simulation, including the optimal solvent volume d (or dex above), the minimum number of cleaning times r, and / or the shortest actual length of the cleaning path, is input into formulas (1) and (2).

[0198] In embodiments where a third state of cleaning is desired, such as Figure 4 As shown, the predetermined area at least includes edge portions such as L1 and L2, and / or a portion of the surface formed by the edge portions.

[0199] In one embodiment, the cleaning / extraction device further includes a support component 1100 that is fixedly connected to the power unit 1000 and has a vertical projection area and weight greater than all the structures described above; it should be noted that when the power unit 1000 is heavy enough and is configured so that the height of the axis of the rotating shaft 1310 from the support surface is greater than the sum of the length of the connecting shaft 1313 and the diagonal length of the wafer box 1200, there is no need to set up a separate support component 1100, and the applicant will not elaborate on it here.

[0200] The present invention provides a device for extracting contaminants from wafer boxes, which uses machinery and programs to replace manual labor to accurately adjust the cleaning process in real time according to the optimal cleaning path, thereby achieving uniform standard cleaning for all wafer boxes, with low solvent / extraction liquid usage and cost savings.

[0201] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, any equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A method for extracting contaminants from a wafer cassette, comprising: Step S1: adding a solvent into the wafer box, wherein the volume of the solvent is 5% to 20% of the volume of the wafer box; Step S2: adjusting the wafer cassette to a first state, with the first surface of the wafer cassette horizontal and facing upward, and rotating the wafer cassette around an axis to clean four surfaces including the first surface; Step S3: Adjust to the second state, make the first surface vertical, rotate the wafer box around the axis, and clean the remaining two surfaces: Step S4: adjusting to a third state, tilting the first surface, and rotating the wafer box around the axis to clean a predetermined area; Step S5: removing the solvent, analyzing and calculating the contaminant content level; The first state and the third state have a plurality of initial rotation positions, the first state and the third state have a plurality of intermediate rotation positions, and the first state, the second state and the third state enable n points on the inner surface of the wafer box to be cleaned to the same degree; The cleaning process includes any one of the permutations and combinations of steps S2, S3, and S4, each of which is performed once; or, the cleaning process includes any one of the permutations and combinations of steps S2, S3, and S4, each of which is performed multiple times; The duration of the first state and the second state is related to the cleaning area ratio; The first state is that the wafer box rotates vertically to clean the four surfaces, and the second state is that the wafer box rotates horizontally to clean the two surfaces; the cleaning process satisfies formula (3): ak=Qi / Qii Qi=q{a6*f(d,vi),a6*s(vi),a8*e(d,s)} Qii=q{a6*f(d,vii),a7*s(vii),a8*e(d,s)} (3) Among them, the value range of a is 0.1~10, k is the cleaning area ratio of the first state to the second state, Qi is the cleaning degree in the first state, and Qii is the cleaning degree in the second state; the pressure f of the solvent on the inner surface of the wafer box is a function of the solvent amount d and the solvent speed v, the solvent distance s is a function of the solvent speed v, and the effective amount of cleaning component e is a function of the solvent amount d and the distance s; a6, a7, and a8 are the weighted relationships between the pressure f of the solvent on the inner surface of the wafer box, the distance s traveled by the solvent, and the effective amount of solvent cleaning component e, respectively, a6+a7+a8=1 or the value range of a6, a7, and a8 is 0.1~10.

2. The method according to claim 1, characterized in that The first surface is a top surface of the wafer cassette.

3. The method according to claim 1, characterized in that The predetermined area at least includes an edge portion and / or a portion of a surface formed by the edge portion.

4. The method according to claim 1, wherein In step S1 , the wafer box is horizontally facing the first surface, and solvent is added into the wafer box, with the amount of solvent at least immersing the bottom surface opposite to the first surface, or the amount of solvent at least immersing the edge of the bottom surface opposite to the first surface.

5. The method according to claim 1, wherein a6=a8=0, the distance traveled by the solvent in the first state and the second state is equal, and the respective cleaning degrees Qi and Qii can be expressed as: Qi=s(vi)=∫vitidt Qii=s(vii)=∫viitiidt Where, s(vi) and s(vii) are the distances traveled by the solvents in the first state and the second state respectively, vi and vii are the velocities of the solvents in the first state and the second state respectively, and ti and tii are the durations of the first state and the second state respectively.

6. The method according to claim 5, characterized in that Step S2 is executed prior to step S3, and e(d, s(vi)) ≥ e(d, s(vii)); or, Step S3 is executed prior to step S2, and e(d, s(vi)) ≤ e(d, s(vii)).

7. The method according to claim 1, characterized in that The cleaning process after the r-th cleaning of the n-th point satisfies formula (1): Qnr = ∑qnr{a1*f(d, vnr), a2*s(vnr, r, r’), a3*e(d, r, r’)} Q1r = Q2r = Q3r = … Qnr (1) Where, r is the number of cleaning times, r is a natural number greater than or equal to 2, and e(d, r, r’) < e(d, r - 1, r - 1’); qnr is the cleaning amount of the solvent for the r-th cleaning of the n-th point, and qnr is the functional relationship among the pressure f of the solvent for the r-th cleaning of the n-th point, the distance s that the solvent passes through the n-th point, and the effective amount e of the cleaning component of the solvent for the r-th cleaning of the n-th point. f is a function of the solvent amount d and the r-th velocity vnr, s is a function of the r-th velocity vnr and the number of cleaning times r, e is a function of the solvent amount d, the number of cleaning times r, and the redundancy amount r’ of the times. a1, a2, and a3 are the weight relationships among the pressure f of the solvent for the r-th cleaning of the n-th point, the distance s that the solvent passes through the n-th point, and the effective amount e of the cleaning component of the solvent for the r-th cleaning of the n-th point respectively, and a1 + a2 + a3 = 1 or the value ranges of a1, a2, and a3 are 0.1 to 10.

8. The method according to claim 7, characterized in that qnr is the cleaning amount of the solvent for the r-th cleaning of the n-th point, qnr-1 is the cleaning amount of the solvent for the (r - 1)-th cleaning of the n-th point, and qnr-2 is the cleaning amount of the solvent for the (r - 2)-th cleaning of the n-th point; when qnr, qnr-1, and qnr-2 satisfy formula (2), the cleaning ends: a5*qnr-2 = qnr + a4*qnr-1 (2) Wherein, the value range of a5 is 0.01-0.2, and the value range of a4 is 0.1-0.3; or, a4 and a5 are both positive numbers less than 1, satisfying a5=1 / 2*a4 2 .

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