Disclosure of Invention
The application provides a silicon wafer drying treatment method and system and electronic equipment, which can avoid forming water marks on the surface of a silicon wafer in the drying process, improve the drying effect and drying speed of the silicon wafer and improve the yield of finished products of the silicon wafer.
In a first aspect, the present application provides a method for drying a silicon wafer, where the method includes:
step 1: heating the air around the silicon wafer;
step 2: introducing ozone gas into the heated air so as to dehumidify the surface of the silicon wafer through the ozone gas and the heated air;
step 3: and (3) carrying out dewatering and drying treatment on the dehumidified air to obtain low-humidity air, guiding the low-humidity air into the periphery of the silicon wafer, and circularly executing the steps (1-3) until the preset first drying condition is met.
According to the method, in the process of drying the surface of the silicon wafer, ozone gas is introduced simultaneously to carry out chemical reaction treatment on pollutants on the surface of the silicon wafer, and the moisture on the surface of the silicon wafer is dried again by the heat released by the chemical reaction, so that the drying effect and the drying speed of the silicon wafer are improved, water marks on the surface of the silicon wafer in the drying process can be avoided, and the yield of finished products of the silicon wafer is improved.
In one possible design, the dehydrating and drying the dehumidified air includes:
carrying out dewatering and drying treatment on the dehumidified air;
heating the air subjected to the dewatering and drying treatment to dehumidify the surface of the silicon wafer through the heated air again;
and carrying out dewatering and drying treatment on the dehumidified air again until a preset second drying condition is met.
According to the method, at least two times of hot air drying treatment are carried out on the surface of the silicon wafer, ozone gas is introduced in the last hot air drying treatment process to carry out chemical reaction treatment on pollutants on the surface of the silicon wafer (namely, the step 1 is returned), and moisture on the surface of the silicon wafer is dried again through heat released by the chemical reaction, so that the drying effect and the drying speed of the silicon wafer can be improved again, and the finished product qualification rate of the silicon wafer is higher.
In one possible design, the dehydrating and drying the hot and humid air obtained after the dehumidifying treatment includes:
detecting the humidity of the air subjected to the dewatering and drying treatment;
when the humidity value of the air obtained through the dewatering and drying treatment is smaller than a set threshold value, outputting the air after the dewatering and drying treatment to perform heating treatment;
and when the humidity value of the air subjected to the dewatering and drying treatment is larger than the set threshold value, continuing to carry out the dewatering and drying treatment.
In one possible design, the first drying condition includes: the circulation times of the steps 1-3 reach the set circulation drying times.
In one possible design, the second drying condition includes: the times of the dewatering and drying treatment of the air reach the set dewatering and drying times.
In a second aspect, the present application provides a silicon wafer drying processing system, including: a controller, a drying device, an ozone adding device and a dehumidifying device;
the drying device is used for executing the step 1: heating the air around the silicon wafer;
the ozone adding device is used for executing the step 2: introducing ozone gas into the heated air so as to dehumidify the surface of the silicon wafer through the ozone gas and the heated air;
the dehumidification device is used for executing the step 3: carrying out dewatering and drying treatment on the dehumidified air to obtain low-humidity air, and guiding the low-humidity air into the periphery of the silicon wafer under control of low humidity so as to circularly execute the steps 1-3;
and the controller is used for controlling the drying equipment, the ozone adding equipment and the dehumidifying equipment to stop when a preset first drying condition is met so as to finish the drying treatment of the silicon wafer.
In one possible design, the dehumidifying device is used for carrying out the dewatering and drying treatment on the dehumidified air during the dewatering and drying treatment;
the drying equipment is used for heating the air subjected to the dewatering and drying treatment so as to dehumidify the surface of the silicon wafer through the heated air again;
the dehumidifying equipment is used for carrying out dewatering and drying treatment on the dehumidified air again until a preset second drying condition is met.
In one possible design, the silicon wafer drying treatment system further comprises a humidity sensor;
the humidity sensor is used for detecting the humidity of the air subjected to the dewatering and drying treatment in the dehumidification equipment;
when the humidity value of the air obtained through the dewatering and drying treatment is smaller than a set threshold value, the humidity sensor is used for outputting the air obtained through the dewatering and drying treatment to the drying equipment so as to heat the output air;
and when the humidity value of the air subjected to the dewatering and drying treatment is larger than the set threshold value, the dehumidifying equipment is used for continuing to carry out the dewatering and drying treatment on the air.
In one possible design, the first drying condition includes: the circulation times of the steps 1-3 reach the set circulation drying times.
In one possible design, the second drying condition includes: the times of the dewatering and drying treatment of the air reach the set dewatering and drying times.
The technical effects of each aspect and the possible technical effects of each aspect in the second aspect are referred to above for the first aspect or the technical effects that may be achieved by each possible solution in the first aspect, and the detailed description is not repeated here.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present application more apparent, the present application will be described in further detail with reference to the accompanying drawings. The specific method of operation in the method embodiment may also be applied to the device embodiment or the system embodiment. It should be noted that "a plurality of" is understood as "at least two" in the description of the present application. "and/or", describes an association relationship of an association object, and indicates that there may be three relationships, for example, a and/or B, and may indicate: a exists alone, A and B exist together, and B exists alone. A is connected with B, and can be represented as follows: both cases of direct connection of A and B and connection of A and B through C. In addition, in the description of the present application, the words "first," "second," and the like are used merely for distinguishing between the descriptions and not be construed as indicating or implying a relative importance or order.
Embodiments of the present application are described in detail below with reference to the accompanying drawings.
Embodiment one:
fig. 1 is a flowchart of a method for drying a silicon wafer according to an embodiment of the present application, where the method includes:
step 1: heating the air around the silicon wafer;
step 2: introducing ozone gas into the heated air so as to dehumidify the surface of the silicon wafer through the ozone gas and the heated air;
step 3: and (3) carrying out dewatering and drying treatment on the dehumidified air to obtain low-humidity air, guiding the low-humidity air into the periphery of the silicon wafer, and circularly executing the steps (1-3) until the preset first drying condition is met.
Wherein, the first drying condition includes: the circulation times of the steps 1-3 reach the set circulation drying times.
Specifically, before the drying treatment is performed on the silicon wafer, the silicon wafer is further required to be automatically fed in sequence, the silicon wafer is subjected to first ultrasonic cleaning, the silicon wafer is subjected to second ultrasonic cleaning, the silicon wafer is subjected to first ultrasonic alkaline cleaning, the silicon wafer is subjected to second ultrasonic alkaline cleaning, the silicon wafer subjected to alkaline cleaning is subjected to first ultrasonic rinsing, the silicon wafer is subjected to second ultrasonic rinsing, the silicon wafer is subjected to third ultrasonic rinsing, then the rinsed silicon wafer is subjected to reserved pickling, after the pickling is completed, the silicon wafer is subjected to second ultrasonic rinsing, slow-pull dehydration is performed, and finally the hot air drying treatment of the steps 1-3 is performed.
Before the drying treatment is carried out, the effectiveness of the water removal effect of the silicon wafer can be verified in the following manner.
Total material moisture content: w = moisture content in total mass/total mass;
silicon wafer relative water content: x = moisture content in total material/mass of silicon wafer;
then there are conversion formulas of total material water content and silicon wafer relative water content, such as:
x=w/1-W or w=x/1+x;
continuing to set Gj: absolute mass of the silicon wafer;
gs: total mass before drying;
gg: total mass of the dried materials;
xs: the relative water content of the wet silicon wafer;
xg: the relative water content of the silicon wafer after drying;
the water evaporation amount formula is calculated using the total material water content:
W=Gs-Gg=Gs*(Ws-Wg)/1-Wg
=Gg*(Ws-Wg)/1-Ws;
calculating a water evaporation capacity formula by using the relative water content of the silicon wafer:
W=GJ*(Xs-Xg);
continuing to set Ws: moisture content of total substances of the wet silicon wafer;
wg: the water content of the total substances after the silicon wafer is dried;
l: absolute dry air consumption;
hs: the relative water content of the air entering the silicon chip after heating;
hg: the relative water content of air after drying the silicon wafer;
i: consumption per unit dry air;
then, the evaporation amount of the moisture is calculated by the absolute dry air consumption amount:
W=L(Hg-Hs);
L=W/(Hg-Hs);
the unit dry air consumption i=l/w=1/(Hg-HS).
When (Hg-HS) ∈+_C, the I value is the smallest, i.e., the unit air consumption is the smallest. That is, when Hg is E++ and HS is E- & lt- & gt, the drying efficiency is highest.
HS is E-oc, namely, the humidity of air is required to be close to zero before entering a silicon wafer; hg is epsilon + to ensure that the air humidity of the dried silicon wafer approaches 100 percent; when the air heating temperature is fixed, the humidity of the air before heating the silicon wafer can be reduced to be zero as much as possible only by a centrifugal machine or a dehumidifier.
The above process is a process and a control process for hot air, and in this embodiment, in addition to drying a silicon wafer by hot air, ozone gas is introduced into the silicon wafer drying process, and moisture on the surface of the silicon wafer is dried by the ozone gas and heated air.
Specifically, the drying of the silicon chip is realized by a drying device, and a dehumidifying device and an ozone adding device can be additionally arranged on the drying device, so that the drying speed and the drying effect can be accelerated by a physical-chemical reaction. The drying equipment is provided with a drying chamber for placing the silicon wafer, a heater is arranged below the drying chamber and used for heating air, and a hot air outlet is arranged above the drying chamber and used for guiding the air heated by the heater into the drying chamber so as to dry the silicon wafer. The air outlet pipeline of the dehumidifying equipment is communicated with the air pipeline of the heater of the drying equipment and is used for guiding the air subjected to the dewatering and drying treatment into the heater for heating; the air inlet pipeline of the dehumidification device is communicated with the drying chamber of the drying device and is positioned above the drying chamber, and the air after the dehumidification treatment of the silicon wafer is recovered to the dehumidification device so as to carry out the dewatering and drying treatment. The ozone adding device is communicated with the drying chamber of the drying device and is used for adding ozone gas of the drying device into air blown out from the hot air outlet of the drying device so as to jointly dehumidify and dry the silicon wafer, and the specific structure is shown in figure 2.
After the hot air is dried, water molecules on the silicon wafer are less in residue and are concentrated at the lower end of the silicon wafer, as shown in fig. 3, when ozone gas enters the drying chamber, the ozone gas is immediately decomposed into oxygen molecules and oxygen atoms, the oxygen atoms can react with the water molecules remained on the silicon wafer rapidly to generate carboxyl free radicals, and the surface of the silicon wafer is also provided with a plurality of organic pollution sources even after being cleaned, so that the generated carboxyl free radicals can be exactly chemically reacted with the pollutants to neutralize the pollutants. The specific chemical reaction process is as follows:
O 3 ===O 2 +O (oxygen atom);
2O 3 ===3O 2 +285KJ;
2H 2 O+2O===4OH;
oh+organic contaminants= = carbon dioxide and mineral salts
The chemical reaction will generate heat which can be provided to the air heating of the dried wafer.
Further, in addition to the above reaction process, silicon and silicon dioxide react with water and oxygen as follows:
Si+2H 2 o (vapor state) = SiO 2 +2H 2 ;
Si+3H 2 O==H 2 SiO 3 +2H 2 ;
Si+O 2 +H 2 O==H 2 SiO 3 ;
A large amount of water is consumed in the chemical reaction process, so that the surface of the silicon wafer is further dried. It should be noted that, in the embodiment of the present invention, the temperature of the drying chamber is 90 degrees to 100 degrees, and under such temperature conditions, the higher the temperature, the more severe the chemical reaction.
The silicon dioxide generated in the high-temperature oxygen-enriched environment in the drying equipment has the characteristics of compact structure, drying, good uniformity and repeatability, the silicon dioxide is an atomic crystal, and the size of the crystal structure is 2.27 angstroms (0.227 nanometers); the crystal size of the water molecules was 3.3 angstrom (0.33 nm). Under the condition, the silicon dioxide crystal with a compact structure is difficult to embed water molecules, so that the adhesion force of the water molecules on the oxide layer on the surface of the silicon wafer is very small, and the water can be quickly taken away by the drying gas, thereby accelerating the evaporation speed of the water molecules on the silicon wafer.
According to the method, in the process of drying the surface of the silicon wafer, ozone gas is introduced at the same time to carry out chemical reaction treatment on pollutants on the surface of the silicon wafer, and the moisture on the surface of the silicon wafer is dried again by the heat released by the chemical reaction, so that the drying effect and the drying speed of the silicon wafer are improved, water marks on the surface of the silicon wafer in the drying process can be avoided, and the yield of finished products of the silicon wafer is improved.
In an alternative embodiment, the dewatering and drying treatment on the dehumidified air includes:
carrying out dewatering and drying treatment on the dehumidified air;
heating the air subjected to the dewatering and drying treatment to dehumidify the surface of the silicon wafer through the heated air again;
and carrying out dewatering and drying treatment on the dehumidified air again until a preset second drying condition is met.
Wherein, the second drying condition includes: the times of the dewatering and drying treatment of the air reach the set dewatering and drying times.
Further, the dewatering and drying treatment for the hot and humid air obtained after the dehumidification treatment comprises the following steps:
detecting the humidity of the air subjected to the dewatering and drying treatment;
when the humidity value of the air obtained through the dewatering and drying treatment is smaller than a set threshold value, outputting the air after the dewatering and drying treatment to perform heating treatment;
and when the humidity value of the air subjected to the dewatering and drying treatment is larger than the set threshold value, continuing to carry out the dewatering and drying treatment.
According to the method, at least two times of hot air drying treatment are carried out on the surface of the silicon wafer, ozone gas is introduced in the last hot air drying treatment process to carry out chemical reaction treatment on pollutants on the surface of the silicon wafer (namely, the step 1 is returned), and moisture on the surface of the silicon wafer is dried again through heat released by the chemical reaction, so that the drying effect and the drying speed of the silicon wafer can be improved again, and the finished product qualification rate of the silicon wafer is higher.
The flow of the drying process of the silicon wafer will be described below by taking the example of performing the hot air drying process on the silicon wafer twice as shown in fig. 4.
(1) The heater heats air and guides the air to the surface of the silicon wafer so that the heated air takes away moisture on the surface of the silicon wafer;
(2) Ozone gas is added into a drying chamber, so that the ozone gas is decomposed into oxygen and oxygen atoms, and the oxygen atoms react with water on the surface of the silicon wafer to further absorb or squeeze away the water on the surface of the silicon wafer;
(3) The dehumidification equipment recovers the hot humidity air obtained in the steps (1) and (2) and carries out dewatering and drying treatment;
(4) Heating the hot humidity air in the step (3) by using a heater again to obtain low-humidity hot air, and guiding the low-humidity hot air to the surface of the silicon wafer so as to quickly take away moisture on the surface of the silicon wafer;
(5) And (3) the dehumidification equipment recovers the hot humidity air obtained in the step (4), and carries out water removal and drying treatment for the second time, and the step (1) is returned.
According to the method, the surface of the silicon wafer is subjected to two times of hot air drying treatment, ozone gas is introduced in the first time of hot air drying treatment to carry out chemical reaction treatment on pollutants on the surface of the silicon wafer, and the moisture on the surface of the silicon wafer is dried again by the heat released by the chemical reaction, and the second time of hot air drying treatment is to recover hot humidity air to carry out heating and drying again after the first time of hot air drying treatment, so that the drying effect and the drying speed of the silicon wafer can be improved again, and the yield of finished products of the silicon wafer is higher.
Example two
Fig. 2 is a schematic diagram of a silicon wafer drying apparatus according to an embodiment of the present application. The silicon wafer drying treatment system comprises: a controller (not shown), a drying apparatus 1, an ozone adding apparatus 3, and a dehumidifying apparatus 2;
the drying device 1 is configured to perform step 1: heating the air around the silicon wafer;
the ozone adding device 3 is used for executing the step 2: introducing ozone gas into the heated air so as to dehumidify the surface of the silicon wafer through the ozone gas and the heated air;
the dehumidification device 2 is configured to perform step 3: carrying out dewatering and drying treatment on the dehumidified air to obtain low-humidity air, and guiding the low-humidity air into the periphery of the silicon wafer under control of low humidity so as to circularly execute the steps 1-3;
and the controller is used for controlling the drying equipment, the ozone adding equipment and the dehumidifying equipment to stop when a preset first drying condition is met so as to finish the drying treatment of the silicon wafer.
Wherein, the first drying condition includes: the circulation times of the steps 1-3 reach the set circulation drying times.
The dehumidifying device 2 can adopt a centrifugal machine or a dehumidifier to reduce the air humidity as much as possible, so that the air humidity approaches zero, and low-humidity air is obtained.
Illustratively, the drying apparatus is provided with a drying chamber for placing the silicon wafer, a heater is provided below the drying chamber for heating air, and a hot air outlet is provided above the drying chamber for introducing the air heated by the heater into the drying chamber for drying the silicon wafer. The air outlet pipeline of the dehumidifying equipment is communicated with the air pipeline of the heater of the drying equipment and is used for guiding the air subjected to the dewatering and drying treatment into the heater for heating; the air inlet pipeline of the dehumidification device is communicated with the drying chamber of the drying device and is positioned above the drying chamber, and the air after the dehumidification treatment of the silicon wafer is recovered to the dehumidification device so as to carry out the dewatering and drying treatment. The ozone adding device is communicated with the drying chamber of the drying device and is used for adding ozone gas of the drying device into air blown out from the hot air outlet of the drying device so as to dehumidify and dry the silicon wafer together. The hot air outlet is formed in one side of the drying chamber, the high-humidity air recovery port is formed in the other side of the drying chamber, the heater is used for heating air in an air pipeline in the drying chamber and guiding the air to the periphery of a silicon wafer in the drying chamber through the hot air outlet, the ozone adding device is used for adding ozone gas into the air around the silicon wafer through the ozone pipeline of the ozone adding device so that hot air mixed with the ozone gas dries the silicon wafer, the formed hot-humidity air is recovered to the dehumidifying device through the high-humidity air recovery port for dewatering and drying treatment, and the formed low-humidity air is led into the heater of the drying device from the air outlet pipeline for reheating. The controller is electrically connected with the drying equipment, the ozone adding equipment and the dehumidifying equipment and is used for controlling the starting or stopping of the drying equipment, the ozone adding equipment and the dehumidifying equipment.
In an alternative embodiment, the dehumidifying device is used for performing the dewatering and drying treatment on the dehumidified air during the dewatering and drying treatment;
the drying equipment is used for heating the air subjected to the dewatering and drying treatment so as to dehumidify the surface of the silicon wafer through the heated air again;
the dehumidifying equipment is used for carrying out dewatering and drying treatment on the dehumidified air again until a preset second drying condition is met.
Wherein, the second drying condition includes: the times of the dewatering and drying treatment of the air reach the set dewatering and drying times.
In an alternative embodiment, the silicon wafer drying processing system further comprises a humidity sensor;
the humidity sensor is used for detecting the humidity of the air subjected to the dewatering and drying treatment in the dehumidification equipment;
when the humidity value of the air obtained through the dewatering and drying treatment is smaller than a set threshold value, the humidity sensor is used for outputting the air obtained through the dewatering and drying treatment to the drying equipment so as to heat the output air;
and when the humidity value of the air subjected to the dewatering and drying treatment is larger than the set threshold value, the dehumidifying equipment is used for continuing to carry out the dewatering and drying treatment on the air.
The technical effects of each aspect and the possible technical effects of each aspect in the second aspect are referred to above for the first aspect or the technical effects that may be achieved by each possible solution in the first aspect, and the detailed description is not repeated here.
It will be apparent to those skilled in the art that various modifications and variations can be made in the present application without departing from the spirit or scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims and the equivalents thereof, the present application is intended to cover such modifications and variations.