TWI840129B - Preparation device and method for metal ion detection sample on wafer surface - Google Patents

Abstract

The present invention discloses a preparation device and method for metal ion detection samples on wafer surfaces; the preparation device comprises: a transparent sealed box; a plurality of liquid containing units arranged in the sealed box, including a liquid tank to be tested and a constant volume liquid tank; a support table arranged in the sealed box, the support table being used to support the container; a quantitative solution extraction unit arranged in the sealed box, the quantitative solution extraction unit being used to extract a set volume of liquid from the plurality of liquid containing units into the container respectively; a heating unit arranged in the sealed box and located below the support table, the heating unit being used to heat the container containing the liquid to be tested to evaporate and remove the liquid in the container.

Description

Preparation device and method for metal ion detection sample on wafer surface

The present invention belongs to the field of wafer detection technology, and in particular to a preparation device and method for metal ion detection samples on wafer surfaces.

Since the birth of solid-state electronic components, the importance of wafer substrate surface cleaning has been recognized in the process of semiconductor microelectronic component manufacturing. The performance, stability and circuit yield of silicon components are greatly affected by metal impurity contamination on the wafer surface. Currently, due to the extreme sensitivity of semiconductor surfaces and the submicron size characteristics of components, the requirements for effective cleaning of raw wafers are getting higher and higher. For the current wafer requirements, the total metal contamination should be less than 10 ¹⁰ / ^cm2 , and the number of particles larger than 0.1μm should be less than 0.1 per square centimeter, that is, on an 8-inch wafer, the number of particles is required to be less than 30.

At present, the detection process of metal impurities on the wafer surface includes: using SC-1 cleaning solution and SC-2 cleaning solution to clean the wafer surface so that the metal impurities on the wafer surface are deposited in the cleaning solution, and then evaporating the cleaning solution containing metal impurities to dryness, and after constant volume, using an inductively coupled plasma mass spectrometer to measure the metal impurity content therein. However, the traditional SC-1 cleaning solution and SC-2 cleaning solution are mainly composed of ammonia water and hydrogen peroxide. Therefore, in the process of evaporating the cleaning solution containing metal impurities to dryness, ammonia will volatilize, and the volatilized ammonia will cause serious damage to the health of technicians.

In view of this, the present invention hopes to provide a device and method for preparing samples for metal ion detection on the surface of a wafer; the cleaning solution containing metal impurities can be automatically or semi-automatically fixed to obtain a sample for detecting the metal ion content on the surface of the wafer, thereby reducing manual participation and avoiding the occurrence of safety issues for technical personnel.

The technical solution of the present invention is implemented as follows: In the first aspect, the present invention provides a sample preparation device for metal ion detection on a wafer surface, the preparation device comprising: a transparent sealed box; a plurality of liquid storage units arranged in the sealed box, including a liquid tank to be tested and a constant-volume liquid tank; a supporting platform arranged in the sealed box, the supporting platform being used to support the container; a quantitative solution extraction unit arranged in the sealed box, the quantitative solution extraction unit being used to extract a set volume of liquid from the plurality of liquid storage units into the container respectively; a heating unit arranged in the sealed box and located below the supporting platform, the heating unit being used to heat the container containing the liquid to be tested to evaporate and remove the liquid in the container.

In a second aspect, the present invention provides a method for preparing a sample for detecting metal ions on a wafer surface. The method can be applied to the preparation device of the first aspect, and the method comprises: sucking a set volume of cleaning liquid containing metal impurities from a test liquid tank into a container by a quantitative solution extraction unit; heating the liquid in the container until it is evaporated and removed by a heating unit; and sucking a set amount of a fixed volume of liquid from a fixed volume liquid tank into a container by a quantitative solution extraction unit for constant volume to obtain a sample for detecting the metal ion content on a wafer surface.

The present invention provides a preparation device and method for a sample for metal ion detection on a wafer surface. In order to obtain the metal ion content on the wafer surface, in the present invention, a cleaning liquid containing metal impurities after the wafer is cleaned is loaded into a liquid tank to be tested, and a sealed box is sealed in time. Then, a set volume of the liquid to be tested in the liquid tank to be tested is absorbed into a container by a quantitative solution extraction unit, and the cleaning liquid in the container is heated by a heating unit until it is evaporated and removed. A quantitative fixed volume liquid is added to the residue after evaporation and removal to fix the volume to obtain a sample that can be used for metal ion content detection on the wafer surface.

The technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiment of the present invention.

Refer to Figure 1, which shows the composition of a preparation device 1 for wafer surface metal ion detection samples provided by an embodiment of the present invention, wherein the preparation device 1 includes: a transparent sealed box 10; a plurality of liquid containing units 20 disposed in the sealed box 10, including a test liquid tank 201 and a constant volume liquid tank 202; a support table 30 disposed in the sealed box 10, the support table 30 is used to support a container 40; a quantitative solution extraction unit 50 disposed in the sealed box 10, the quantitative solution extraction unit 50 is used to extract a set volume of liquid from the plurality of liquid containing units 20 into the container 40 respectively; a heating unit 60 disposed in the sealed box 10 and located below the support table 30, the heating unit 60 is used to heat the container 40 containing the test liquid to evaporate and remove the liquid in the container 40.

It can be understood that in order to obtain the metal ion content on the wafer surface, in the embodiment of the present invention, the cleaning liquid containing metal impurities after the wafer is cleaned is loaded into the test liquid tank 201, and the sealed box 10 is sealed in time, and then the set volume of the test liquid in the test liquid tank 201 is absorbed into the container 40 by the quantitative solution extraction unit 50, and the cleaning liquid in the container 40 is heated by the heating unit 60 until it is evaporated and removed, and a certain amount of fixed volume liquid is added to the residue after evaporation to fix the volume to obtain a sample that can be used for detecting the metal ion content on the wafer surface.

It can be understood that, in the specific implementation process, before the SC-1 cleaning solution and the SC-2 cleaning solution used to clean the metal impurities on the wafer surface are used to clean the wafer surface, if there are metal impurities in the SC-1 cleaning solution and the SC-2 cleaning solution, the preparation device 1 shown in FIG. 1 can also be used to obtain a sample for detecting the metal ion content in the SC-1 cleaning solution and the SC-2 cleaning solution, thereby obtaining the metal impurity content in the SC-1 cleaning solution and the SC-2 cleaning solution. Therefore, the accurate content of metal ions on the wafer surface can be obtained as the metal ion content obtained from the sample for detecting the metal ion content on the wafer surface minus the metal impurity content in the SC-1 cleaning solution and the SC-2 cleaning solution.

In addition, it can be understood that in the embodiment of the present invention, the sealing box 10 is provided to prevent human body damage caused by the volatility of ammonia when evaporating and removing the liquid in the container 40, and the transparent sealing box 10 can facilitate technical personnel to observe the ongoing technical operations.

For the preparation device 1 shown in FIG. 1 , in some possible implementations, the constant volume liquid stored in the constant volume liquid tank 202 is a nitric acid solution with a mass concentration of 1% to 10%; optionally, the constant volume liquid is a nitric acid solution with a mass concentration of 5%.

It should be noted that the set volume of the fixed volume liquid extracted by the quantitative solution extraction unit 50 each time is 5ml~20ml.

For the preparation device 1 shown in Figure 1, in some possible implementations, as shown in Figure 1, the multiple liquid containing units 20 also include a washing liquid tank, and the washing liquid tank includes a first washing liquid tank 203A and a second washing liquid tank 203B; wherein the first washing liquid tank 203A is used to contain hydrofluoric acid (HF) solution, and the second washing liquid tank 203B is used to contain ultrapure water. It can be understood that after the sample obtained by constant volume for detecting the metal ion content on the wafer surface is detected and removed, the container 40, such as a beaker, needs to be cleaned to facilitate the next preparation work. In the embodiment of the present invention, the HF solution in the first washing liquid tank 203A can be used to pickle the residual metal impurities in the container 40, and then the ultrapure water in the second washing liquid tank 203B can be used to clean the container 40 to obtain a clean container 40, which will not affect the measurement of the metal impurity content in the liquid to be tested next time.

For the preparation device 1 shown in Figure 1, in some possible implementations, as shown in Figure 1, the quantitative solution extraction unit 50 includes: a robot arm 501 with three degrees of freedom; a suction nozzle 502 arranged at the front end of the robot arm 501, and the suction nozzle 502 is used to suck a set volume of liquid from a plurality of liquid containing units 20 into a container 40 respectively.

It can be understood that in the specific implementation process, first, a set volume of cleaning liquid containing metal impurities is sucked from the test liquid tank 201 into the container 40 by the quantitative solution extraction unit 50. After the liquid in the container 40 is evaporated and removed by the heating unit 60, a certain amount of fixed volume liquid is sucked from the fixed volume liquid tank 202 into the container 40 for fixed volume. It should be noted that in order to ensure the accuracy of the fixed volume, the quantitative solution extraction unit 50 can be set to suck a small amount of fixed volume liquid from the fixed volume liquid tank 202 more than once; when a sample that can be used for the detection of the metal ion content on the wafer surface is obtained, after the detection is completed and the sample is removed, the quantitative solution extraction unit 50 is used to suck HF solution and ultrapure water from the first washing liquid tank 203A and the second washing liquid tank 203B respectively to clean the container 40.

It should be noted that, in the specific implementation process, the robot arm 501 and the suction nozzle 502 are arranged inside the sealed box 10. In order to control the movement of the robot arm 501, the control unit 503 connected thereto is arranged outside the sealed box 10.

For the above-mentioned implementation, in some examples, as shown in FIG. 2 , a plurality of supporting tables 30 may be provided in the preparation device 1 to support a plurality of containers 40 ; wherein a heating unit 60 is provided under each supporting table 30 .

It can be understood that multiple carriers 30 are provided to hold multiple containers 40. In a specific implementation process, multiple groups of samples for detecting the metal ion content on the wafer surface can be obtained simultaneously to obtain the accurate content of the metal ions on the wafer surface.

For the preparation device shown in Figure 1, in some possible implementations, as shown in Figure 3, the quantitative solution extraction unit 50 includes: a plurality of liquid pipelines 31 connected to each liquid storage unit 20, the plurality of liquid pipelines 31 are used to respectively draw a set volume of liquid from the plurality of liquid storage units 20 into the container 40; a switch unit 32 arranged on each liquid pipeline 31, the switch unit 32 is used to control the connection or closing of the corresponding liquid pipeline 31.

It can be understood that in the specific implementation process, as shown in Figure 3, the liquid pipeline 31 connected to the test liquid tank 201 is first opened to allow a set volume of cleaning liquid containing metal impurities to flow into the container 40. After the liquid in the container 40 is evaporated and removed by the heating unit 60, the liquid pipeline 31 connected to the constant volume liquid tank 202 is opened to allow a certain amount of constant volume liquid to flow into the container 40 for constant volume; when a sample that can be used for wafer surface metal ion content detection is obtained, after the detection is completed and the sample is removed, the liquid pipelines 31 connected to the first washing liquid tank 203A and the second washing liquid tank 203B are opened in turn to allow HF solution and ultrapure water to clean the container 40 in turn.

It should be noted that, in the specific implementation process, each switch unit 32 is connected to a switch control unit (not shown in the figure) to facilitate timely connection or closing of the liquid pipeline 31.

For the preparation device 1 shown in FIG. 2 , in some possible implementations, the heating unit 60 is connected to a power controller 70 , and the power controller 70 is used to control the heating unit 60 to heat the liquid in the container 40 at a set power.

It should be noted that, regarding the setting of the power controller 70, in the specific implementation process, as shown in Figure 2 or Figure 3, only one power controller 70 can be set in the preparation device 1. Regardless of whether one heating unit 60 or multiple heating units 60 are set in the preparation device 1, heating control is performed through one power controller 70.

Of course, in the specific implementation process, when the preparation device 1 includes multiple heating units 60, each heating unit 60 can also be connected to a power controller 70, so that when the container 40 placed in front contains cleaning liquid, the heating and evaporation removal operation can be performed first, and the subsequent containers 40 can be heated and evaporated in turn, thereby saving time and improving detection efficiency.

For the preparation device 1 shown in FIG. 1 , in some possible implementations, as shown in FIG. 1 , the preparation device 1 further includes a ventilation duct 80 disposed at the top of the sealed box 10. It can be understood that the cleaning solution used to clean the metal ions on the surface of the wafer contains ammonia water, which will cause damage to the technicians after evaporating into ammonia gas. Therefore, in the embodiment of the present invention, the ventilation duct 80 is used to discharge the volatile ammonia gas to avoid causing damage to the technicians when the technicians remove the obtained samples that can be used for detecting the metal ion content on the wafer surface.

Referring to FIG. 4 , it shows a method for preparing a sample for metal ion detection on a wafer surface provided by an embodiment of the present invention. The method can be applied to the preparation device 1 of the aforementioned technical solution. The method specifically includes:

S401, a set volume of cleaning liquid containing metal impurities is drawn from the test liquid tank 201 into the container 40 through the quantitative solution extraction unit 50;

S402, using the heating unit 60 to heat the liquid in the container 40 until it evaporates and is removed;

S403, using the quantitative solution extraction unit 50 to draw a set amount of the constant volume liquid from the constant volume liquid tank 202 into the container 40 for constant volume to obtain a sample for detecting the metal ion content on the wafer surface.

For the technical solution shown in FIG. 4 , in some examples, the preparation method further includes: after obtaining a sample for detecting the metal ion content on the wafer surface, using a quantitative solution extraction unit 50 to sequentially draw HF solution and ultrapure water from the first washing liquid tank 203A and the second washing liquid tank 203B to clean the container 40.

It should be noted that the technical solutions described in the embodiments of the present invention can be combined arbitrarily without conflict.

The above is only a specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person familiar with the technical field and with ordinary knowledge within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the patent application.

1: Preparation device 10: Sealed box 20: Liquid storage unit 201: Test liquid tank 202: Constant volume liquid tank 203A: First washing liquid tank 203B: Second washing liquid tank 30: Carrier 31: Liquid pipeline 32: Switch unit 40: Container 50: Quantitative solution extraction unit 501: Robotic arm 502: Suction nozzle 503: Control unit 60: Heating unit 70: Power controller 80: Ventilation pipeline S401~S403: Step flow

FIG1 is a schematic diagram of the composition of a preparation device for metal ion detection samples on wafer surfaces provided in one embodiment of the present invention; FIG2 is a schematic diagram of the composition of a preparation device for metal ion detection samples on wafer surfaces provided in another embodiment of the present invention; FIG3 is a schematic diagram of the composition of a preparation device for metal ion detection samples on wafer surfaces provided in another embodiment of the present invention; FIG4 is a schematic diagram of the process of a preparation method for metal ion detection samples on wafer surfaces provided in an embodiment of the present invention.

1: Preparation equipment

10: Sealed box

20: Liquid storage unit

201: Liquid tank to be tested

202: Constant volume liquid tank

203A: First washing liquid tank

203B: Second washing liquid tank

30: Carrier platform

40:Container

50: Quantitative solution extraction unit

501:Robotic Arm

502: Nozzle

503: Control unit

60: Heating unit

80: Ventilation duct

Claims (9)

A preparation device for metal ion detection samples on wafer surfaces, comprising: a transparent sealed box; a plurality of liquid containing units arranged in the sealed box, including a liquid tank to be tested and a constant volume liquid tank; a support table arranged in the sealed box, the support table is used to support a container; a quantitative solution extraction unit arranged in the sealed box, the quantitative solution extraction unit is used to extract a set volume of liquid from the plurality of liquid containing units respectively. to the container; a heating unit is arranged in the sealed box and below the carrier, the heating unit is used to heat the container containing the liquid to be tested to evaporate and remove the liquid in the container; the plurality of liquid storage units also include a washing liquid tank, the washing liquid tank includes a first washing liquid tank and a second washing liquid tank; wherein the first washing liquid tank is used to contain HF solution, and the second washing liquid tank is used to contain ultrapure water. The preparation device for metal ion detection samples on the wafer surface as described in claim 1, wherein the constant volume liquid stored in the constant volume liquid tank is a nitric acid solution with a mass concentration of 1% to 10%. The preparation device for wafer surface metal ion detection samples as described in claim 1, wherein the quantitative solution extraction unit includes: a robot arm with three degrees of freedom; a suction nozzle disposed at the front end of the robot arm, the suction nozzle is used to suck a set volume of liquid from a plurality of the liquid containing units into the container. As described in claim 3, a preparation device for wafer surface metal ion detection samples, wherein the preparation device can be provided with multiple carriers to carry multiple containers; wherein the heating unit is provided under each carrier. The preparation device for wafer surface metal ion detection sample as described in claim 1, wherein the quantitative solution extraction unit includes: a plurality of liquid pipelines connected to each of the liquid storage units, the liquid pipelines are used to draw a set volume of liquid from the plurality of liquid storage units into the container; a switch unit arranged on each of the liquid pipelines, the switch unit is used to control the connection or closing of the corresponding liquid pipelines. A preparation device for wafer surface metal ion detection samples as described in any one of claims 1 to 5, wherein the heating unit is connected to a power controller, and the power controller is used to control the heating unit to heat the liquid in the container at a set power. A preparation device for wafer surface metal ion detection samples as described in claim 6, wherein the preparation device also includes a ventilation duct arranged at the top of the sealed box. A method for preparing a sample for metal ion detection on a wafer surface is mainly used in a preparation device for metal ion detection on a wafer surface as described in any one of claims 1 to 7, and the steps include: sucking a set volume of cleaning liquid containing metal impurities from the liquid tank to be tested into the container by the quantitative solution extraction unit; heating the liquid in the container until it evaporates and is removed by the heating unit; sucking a set amount of fixed volume liquid from the fixed volume liquid tank into the container by the quantitative solution extraction unit to fix the volume to obtain a sample for detecting the metal ion content on the wafer surface. The method for preparing a sample for detecting metal ions on the surface of a wafer as described in claim 8 further includes: after obtaining the sample for detecting the metal ion content on the surface of the wafer, using the quantitative solution extraction unit to sequentially draw hydrofluoric acid (HF) solution and ultrapure water from the first washing liquid tank and the second washing liquid tank to clean the container.