CN107154340A - Substrate cleaning method and device - Google Patents

Abstract

The invention relates to the technical field of semiconductor manufacturing, in particular to a substrate cleaning method. The method comprises the steps of: rotating the slide table holding the substrate in the reaction chamber; spraying the _CO2 aqueous solution into the reaction chamber to form a water film on the surface of the substrate; spraying the ozone aqueous solution into the reaction chamber oxidizing and removing pollutants on the surface of the substrate. The invention also provides a substrate cleaning device. The present invention sprays a liquid solution containing _CO2 into the reaction chamber, and simultaneously introduces ozone into the reaction chamber, and the ozone oxidizes pollutants and organic coatings on the surface of the substrate, while _CO2 protects the metal on the surface of the substrate from corrosion. The invention can not only exert the advantages of ozone cleaning silicon chips, but also avoid metal corrosion. Moreover, ozone and CO ₂ are cheap and easy to obtain, maintaining economic efficiency and environmental protection.

Description

Method and device for cleaning a substrate

technical field

The invention relates to the technical field of semiconductor manufacturing, in particular to a substrate cleaning method and device.

Background technique

Semiconductor devices are widely used in various communication, medical, industrial, military and household electronic products. These semiconductor devices are all prepared from semiconductor substrates. The size of these devices is generally on the micron scale, and the devices are very sensitive to contaminants, and extremely small organic and metal particles can cause device failure. Therefore, cleaning silicon wafers to remove pollutants is usually a very critical process step in the manufacturing process of semiconductor devices.

For many years, the cleaning of semiconductor substrates is usually divided into three to four separate steps, and the substrates are treated with mixed solutions such as sulfuric acid and hydrogen peroxide. When there is a metal film on the surface of the substrate, it will be cleaned with an organic solvent. These methods are widely used in cleaning semiconductor substrates, but still have some disadvantages. These disadvantages include higher prices of organic chemical cleaning agents, longer times for various cleaning steps, higher consumption of chemical cleaning agents, and inconvenient disposal of cleaning waste liquids. Therefore, extensive research efforts have been made to develop new silicon wafer cleaning technologies.

Recently, the technology of cleaning silicon wafers by mixing ozone with water and diffusing ozone in the water film has begun to be applied in the process of semiconductor chip preparation. This ozone technology has been proven to be effective in cleaning and removing pollutants and organic films on the surface of silicon wafers, and can overcome the shortcomings of traditional acid and hydrogen peroxide mixed liquid cleaning methods. The cleaning process using the ozone diffusion water film can save time, does not need more expensive acid and hydrogen peroxide, and adopts the spraying method, which can save water consumption and equipment placement space.

Ozone diffusion cleaning technology can inject ozone into water, and then spray the ozone water onto the surface of the substrate. When the temperature of the sprayed water is high, the removal efficiency of organic film and pollution on the surface of the silicon wafer will be greatly improved.

When the substrate is exposed to ozone and hot water, some metals in the semiconductor chips on the silicon wafer may be corroded. As the temperature increases during the process, the rates of various reactions increase. Metal corrosion is also getting worse. Dissimilar metals in direct contact will create an electrochemical cell effect that further promotes corrosion.

Many methods are used to reduce and avoid metal corrosion. These methods mainly include reducing the process temperature or adding corrosion inhibitors to the water. Since lowering the temperature will affect the chemical reactivity to remove organic films or pollution, the method of lowering the process temperature is not used in actual production to avoid metal corrosion. Corrosion inhibitors mainly include benzotriazole, silicate, nitrate and so on. In the ozone cleaning process of this blocker, it can be cleaned at a higher temperature, and at the same time, the aluminum wire of the silicon wafer is prevented from being corroded.

Of course, corrosion retarders also have some disadvantages when cleaning semiconductor substrates, such as must be effectively mixed with the process liquid, and different retarders are only effective for specific metals under specific parameters. In a word, there is still a need for a method in the ozone cleaning process, which can prevent the corrosion of metals such as aluminum and copper on the silicon wafer during the cleaning process.

Contents of the invention

The object of the present invention is to provide a substrate cleaning method, which can prevent metals such as aluminum and copper on the substrate from being corroded during the substrate cleaning process.

Another object of the present invention is to provide a substrate cleaning device.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A method for cleaning a substrate, comprising the steps of:

Rotate the carrier stage holding the substrate in the reaction chamber;

Injecting _CO into the reaction chamber Aqueous solution forms a water film on the surface of the substrate;

The ozone aqueous solution is sprayed into the reaction chamber to oxidize and remove the pollutants on the surface of the substrate.

In the above scheme, after spraying the aqueous ozone solution into the reaction chamber to oxidize and remove the pollutants on the surface of the substrate, the following steps are included:

Stop spraying the aqueous ozone solution into the reaction chamber, continue to spray the _CO2 aqueous solution into the reaction chamber, and clean the surface of the substrate;

Stop spraying the CO ₂ aqueous solution into the reaction chamber, and rotate the slide table at high speed, so that the surface of the substrate is dry.

In the above scheme, the preparation of the _CO2 aqueous solution comprises the following steps:

_CO2 uniformly enters the deionized water in the first deionized water tank through the first diffuser to form a _CO2 aqueous solution.

In such scheme, the preparation of described ozone aqueous solution comprises the steps:

Ozone evenly enters the deionized water in the second deionized water tank through the second diffuser to form an ozone aqueous solution.

In the above solution, the temperature of the deionized water in the first deionized water tank is heated to room temperature to 100°C.

In the above solution, the temperature of the deionized water in the second deionized water tank is heated to room temperature to 100°C.

A substrate cleaning device, the device comprising:

a reaction chamber, the reaction chamber is used to clean the substrate;

a slide table, the slide table is arranged in the reaction chamber, and the substrate is placed on the slide table;

a rotation mechanism, the rotation mechanism is arranged at the bottom of the reaction chamber and is connected with the slide table for driving the slide table to rotate;

_CO2 gas source;

A first diffuser, the _CO gas source is connected to the first diffuser through a first gas pipeline;

The first deionized water tank, the first diffuser is arranged in the first deionized water tank, the first diffuser is used to uniformly enter the CO ₂ gas of the CO ₂ gas source into the first deionized water tank Deionized water in an ionized water tank to form a _CO2 aqueous solution;

A first heater, the first heater is arranged in the first deionized water tank, for heating the deionized water in the first deionized water tank;

an ozone generator for generating ozone;

A second diffuser, the ozone generator is connected to the second diffuser through a second gas pipeline;

The second deionized water tank, the second diffuser is arranged in the second deionized water tank, and the second diffuser is used to uniformly enter the ozone produced by the ozone generator into the second deionized water The deionized water in the tank forms an ozone aqueous solution;

A second heater, the second heater is arranged in the second deionized water tank, for heating the deionized water in the second deionized water tank;

The first multi-way valve, the first deionized water tank and the second deionized water tank are respectively connected to the inlet of the first multi-way valve through liquid pipelines;

Nozzle, the nozzle is connected with the outlet of the first multi-way valve, the _CO2 aqueous solution in the first deionized water tank and the ozone aqueous solution in the second deionized water tank respectively pass through the first multi-way valve into the nozzle.

In the above solution, a first pump and a first filter are sequentially arranged on the liquid pipeline between the first deionized water tank and the first multi-way valve.

In the above solution, a second pump and a second filter are sequentially provided on the liquid pipeline between the second deionized water tank and the first multi-way valve.

In the above scheme, the device also includes:

a waste liquid collection port, the waste liquid collection port is arranged at the bottom of the reaction chamber;

A second multi-way valve, the waste liquid collection port is connected to the inlet of the second multi-way valve through a recovery pipeline;

A discharge pipeline, the outlet of the second multi-way valve is respectively connected with the first deionized water tank, the second deionized water tank and the discharge pipeline.

Compared with prior art, the beneficial effect of the present invention is:

The present invention sprays a liquid solution containing _CO2 into the reaction chamber, and simultaneously introduces ozone into the reaction chamber, and the ozone oxidizes pollutants and organic coatings on the surface of the substrate, while _CO2 protects the metal on the surface of the substrate from corrosion. The invention can not only exert the advantages of ozone cleaning silicon chips, but also avoid metal corrosion. Moreover, ozone and CO ₂ are cheap and easy to obtain, maintaining economic efficiency and environmental protection.

Description of drawings

FIG. 1 is a process flow diagram of a substrate cleaning method provided by an embodiment of the present invention.

FIG. 2 is a schematic structural diagram of a substrate cleaning device provided by an embodiment of the present invention.

detailed description

The substrate cleaning principle of the present invention is: spray _CO2 aqueous solution and ozone aqueous solution to the semiconductor substrate surface with metal on the surface, _CO2 aqueous solution protects the metal on the substrate surface from being corroded, and ozone aqueous solution oxidizes the pollutants on the substrate surface remove.

In order to better understand the above-mentioned technical solution, the above-mentioned technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

Embodiment one:

As shown in Figure 1, a kind of substrate cleaning method comprises the steps:

Step 110, rotating the slide stage holding the substrate in the reaction chamber;

Step 120, spraying a _CO2 aqueous solution into the reaction chamber to form a water film on the surface of the substrate;

Specifically, the preparation of the _CO2 aqueous solution includes the following steps: _CO2 uniformly enters the deionized water in the first deionized water tank through the first diffuser to form a _CO2 aqueous solution; The temperature of the deionized water is heated to room temperature ~ 100°C. The CO ₂ aqueous solution can also be heated in the first deionized water tank to become steam, and then injected into the reaction chamber to make the cleaning effect better.

Step 130, spray an aqueous ozone solution into the reaction chamber to oxidize and remove pollutants on the surface of the substrate.

Specifically, the preparation of the ozone aqueous solution includes the following steps: ozone uniformly enters the deionized water in the second deionized water tank through the second diffuser to form an ozone aqueous solution; the deionized water in the second deionized water tank The temperature is heated to room temperature ~ 100 °C.

In this embodiment, after spraying the aqueous ozone solution into the reaction chamber to oxidize and remove the pollutants on the surface of the substrate, the following steps are further included:

Step 140, stop spraying the ozone aqueous solution into the reaction chamber, continue spraying the _CO2 aqueous solution into the reaction chamber, and clean the surface of the substrate;

Step 150, stop spraying the CO ₂ aqueous solution into the reaction chamber, and rotate the slide table at a high speed, so that the surface of the substrate is dried.

Embodiment two:

As shown in Figure 2, the present embodiment provides a substrate cleaning device, the device includes: a reaction chamber 101, the reaction chamber 101 is used to clean the substrate 103; In the reaction chamber 101, the substrate 103 is placed on the loading stage 104; a rotating mechanism 129, the rotating mechanism 129 is arranged at the bottom of the reaction chamber 101 and is connected to the loading stage 104 , used to drive the slide table 104 to rotate, and then drive the substrate 103 to rotate; the CO ₂ gas source 106 can be a CO ₂ storage tank or a CO ₂ generator; the first diffuser 111, the CO ₂ gas Source 106 is connected with described first diffuser 111 through first gas line 127; First deionized water tank 113, described first diffuser 111 is arranged in described first deionized water tank 113, and described first A diffuser 111 is used to uniformly enter the _CO gas of the _CO gas source 106 into the deionized water 110 in the first deionized water tank 113 to form a _CO aqueous solution; the first heater 112, the The first heater 112 is arranged in the first deionized water tank 113, and is used to heat the deionized water in the first deionized water tank 113 to room temperature to 100° C.; the ozone generator 126 uses Ozone is produced; the second diffuser 120, the ozone generator 126 is connected to the second diffuser 120 through the second gas pipeline 125; the second deionized water tank 118, the second diffuser 120 is arranged on In the second deionized water tank 118, the second diffuser 120 is used to uniformly enter the ozone generated by the ozone generator 126 into the deionized water 121 in the second deionized water tank 118 to form Ozone aqueous solution; second heater 119, described second heater 119 is arranged in the described second deionized water tank 118, is used for heating the deionized water in the described second deionized water tank 118, is heated to Room temperature ~ 100°C; the first multi-way valve 130, the first deionized water tank 113 and the second deionized water tank 118 are respectively connected to the inlet of the first multi-way valve 130 through liquid pipelines (108, 123) Nozzle 102, the nozzle 102 is connected with the outlet of the first multi-way valve 130, the CO in the first deionized water tank 113 _The aqueous solution and the ozone aqueous solution in the second deionized water tank 118 are respectively Enter the nozzle 102 through the first multi-way valve 130 .

In this embodiment, a first pump 109 and a first filter 107 are sequentially provided on the liquid pipeline 108 between the first deionized water tank 113 and the first multi-way valve 130; A second pump 122 and a second filter 124 are sequentially provided on the liquid pipeline 123 between the ion water tank 118 and the first multi-way valve 130 .

In this embodiment, the device further includes: a waste liquid collection port 105, the waste liquid collection port 105 is arranged at the bottom of the reaction chamber 101; a second multi-way valve 115, the waste liquid collection port 105 passes through the recovery pipe The road 128 is connected with the 115 inlet of the second multi-way valve; the discharge pipeline 116, the outlet of the second multi-way valve 115 is connected with the first deionized water tank 113 and the second deionized water tank respectively. 118 is connected to the discharge pipeline 116.

The working process of this embodiment is as follows:

When cleaning the pollutants on the surface of the substrate 103, the first step: the rotating mechanism 129 makes the substrate 103 clamped by the slide stage 104 rotate, and the rotation speed is 0-1000rpm; the second step: the first pump 109 works to make the The _CO2 aqueous solution heated in the first deionized water tank 113 enters the liquid pipeline 108, the first filter 107 filters the _CO2 aqueous solution, and the _CO2 aqueous solution passes through the first multi-way valve 130 and enters the nozzle 102 to be sprayed to the rotating the surface of the substrate 103 to form a water film and protect the metal that may exist on the surface of the substrate 103; the third step: the second pump 122 starts to work, so that the heated ozone aqueous solution in the second deionized water tank 118 enters the liquid In the pipeline 123, the second filter 124 removes impurities in the ozone aqueous solution, the ozone aqueous solution enters the nozzle 102 through the first multi-way valve 130, and is sprayed onto the surface of the substrate 103, and the ozone aqueous solution removes pollutants on the substrate 103 surface. Oxidation removal; the 4th step: the second pump 122 stops working, and the ozone aqueous solution is not sprayed onto the substrate 103 surface, and the first pump 109 continues to work, and CO _The aqueous solution is sprayed onto the substrate 103 surface, and the substrate 103 surface is washed; Step 5: The first pump 109 stops working. At this time, no liquid is sprayed onto the surface of the substrate 103. The rotating mechanism 129 makes the substrate 103 clamped by the stage 104 rotate at a high speed of 500-3000 rpm to dry the surface of the substrate 103.

The waste liquid produced in the process of cleaning the substrate 103 is reclaimed through the waste liquid collection port 105 and enters the recovery pipeline 128. The recovery pipeline 128 is connected to the second multi-way valve 115, and the switching of the second multi-way valve 115 can make the waste liquid The waste liquid can be recovered to the first deionized water tank 113 through the pipeline 114 , or recycled to the second deionized water tank 118 through the pipeline 117 , and can also be switched to discharge the waste liquid through the discharge pipeline 116 .

The advantages of the present invention are as follows:

The present invention sprays a liquid solution containing _CO2 into the reaction chamber, and simultaneously introduces ozone into the reaction chamber, and the ozone oxidizes pollutants and organic coatings on the surface of the substrate, while _CO2 protects the metal on the surface of the substrate from corrosion. The invention can not only exert the advantages of ozone cleaning silicon chips, but also avoid metal corrosion. Moreover, ozone and CO ₂ are cheap and easy to obtain, maintaining economic efficiency and environmental protection.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. a substrate cleaning method, is characterized in that, comprises the steps: Rotate the carrier stage holding the substrate in the reaction chamber; Injecting _CO into the reaction chamber Aqueous solution forms a water film on the surface of the substrate; The ozone aqueous solution is sprayed into the reaction chamber to oxidize and remove the pollutants on the surface of the substrate. 2. substrate cleaning method as claimed in claim 1, is characterized in that, in described reaction chamber, spray ozone aqueous solution, after the pollutant oxidation removal of described substrate surface, comprise the steps: Stop spraying the aqueous ozone solution into the reaction chamber, continue to spray the _CO2 aqueous solution into the reaction chamber, and clean the surface of the substrate; Stop spraying the CO ₂ aqueous solution into the reaction chamber, and rotate the slide table at high speed, so that the surface of the substrate is dry. 3. substrate cleaning method as claimed in claim 1, is characterized in that, described CO _The preparation of aqueous solution comprises the steps: _CO2 uniformly enters the deionized water in the first deionized water tank through the first diffuser to form a _CO2 aqueous solution. 4. substrate cleaning method as claimed in claim 1, is characterized in that, the preparation of described ozone aqueous solution comprises the steps: Ozone evenly enters the deionized water in the second deionized water tank through the second diffuser to form an ozone aqueous solution. 5 . The substrate cleaning method according to claim 3 , wherein the temperature of the deionized water in the first deionized water tank is heated to room temperature to 100° C. 6 . 6 . The substrate cleaning method according to claim 4 , wherein the temperature of the deionized water in the second deionized water tank is heated to room temperature˜100° C. 7 . 7. A substrate cleaning device, characterized in that the device comprises: a reaction chamber, the reaction chamber is used to clean the substrate; a slide table, the slide table is arranged in the reaction chamber, and the substrate is placed on the slide table; a rotation mechanism, the rotation mechanism is arranged at the bottom of the reaction chamber and is connected with the slide table for driving the slide table to rotate; _CO2 gas source; A first diffuser, the _CO gas source is connected to the first diffuser through a first gas pipeline; The first deionized water tank, the first diffuser is arranged in the first deionized water tank, the first diffuser is used to uniformly enter the CO ₂ gas of the CO ₂ gas source into the first deionized water tank Deionized water in an ionized water tank to form a _CO2 aqueous solution; A first heater, the first heater is arranged in the first deionized water tank, for heating the deionized water in the first deionized water tank; an ozone generator for generating ozone; A second diffuser, the ozone generator is connected to the second diffuser through a second gas pipeline; The second deionized water tank, the second diffuser is arranged in the second deionized water tank, and the second diffuser is used to uniformly enter the ozone produced by the ozone generator into the second deionized water The deionized water in the tank forms an ozone aqueous solution; A second heater, the second heater is arranged in the second deionized water tank, for heating the deionized water in the second deionized water tank; The first multi-way valve, the first deionized water tank and the second deionized water tank are respectively connected to the inlet of the first multi-way valve through liquid pipelines; Nozzle, the nozzle is connected with the outlet of the first multi-way valve, the _CO2 aqueous solution in the first deionized water tank and the ozone aqueous solution in the second deionized water tank respectively pass through the first multi-way valve into the nozzle. 8. The substrate cleaning device according to claim 7, wherein a first pump and a first filter are sequentially arranged on the liquid pipeline between the first deionized water tank and the first multi-way valve. device. 9. The substrate cleaning device according to claim 7, wherein a second pump and a second filter are sequentially arranged on the liquid pipeline between the second deionized water tank and the first multi-way valve. device. 10. The substrate cleaning device according to claim 7, further comprising: a waste liquid collection port, the waste liquid collection port is arranged at the bottom of the reaction chamber; A second multi-way valve, the waste liquid collection port is connected to the inlet of the second multi-way valve through a recovery pipeline; A discharge pipeline, the outlet of the second multi-way valve is respectively connected with the first deionized water tank, the second deionized water tank and the discharge pipeline.