TWI894031B - Method for forming semiconductor device - Google Patents

Abstract

The present disclosure provides a method for forming a semiconductor device, which includes following steps. A semiconductor substrate is placed into a processing tank. A processing solution is injected into the processing tank to a first level height of the processing tank, such that the semiconductor substrate is immersed in the processing solution completely. The semiconductor substrate is subjected to an oxidation treatment in a manner of standing in the processing solution so as to form an oxide layer on the semiconductor substrate. During the oxidation treatment, the temperature of the processing solution is maintained at about 65°C to about 85°C, and the time for the oxidation treatment is from about 50 minutes to about 100 minutes.

Description

Method for forming semiconductor device

The present invention relates to a method for forming a semiconductor device, and more particularly to a process for repairing a semiconductor substrate during a semiconductor manufacturing process.

In the process of forming semiconductor devices, one or more semiconductor processes are typically used to form structures such as isolation structures used to define active areas, or structures such as through-substrate vias (TSVs) used for electrical connections, in a semiconductor substrate. However, these semiconductor processes typically involve etching the semiconductor substrate to form trenches for the isolation structures or through-hole holes for the TSVs. This can cause a certain degree of damage to the surface of the semiconductor substrate undergoing these processes. As the size of electronic devices continues to shrink and users' performance requirements for electronic devices continue to increase, processes for repairing this damage are becoming increasingly important.

The present invention provides a method for forming a semiconductor device. The method comprises performing an oxidation treatment on a semiconductor substrate by placing it in a treatment solution to form an oxide layer of a desired thickness on the damaged surface of the semiconductor substrate. In this way, damage to the semiconductor substrate caused by processes such as etching can be effectively repaired.

One embodiment of the present invention provides a method for forming a semiconductor device, comprising the following steps: placing a semiconductor substrate in a processing tank; injecting a processing liquid into the processing tank to a first level of the processing tank so that the semiconductor substrate is completely immersed in the processing liquid; and performing an oxidation treatment on the semiconductor substrate while stationary in the processing liquid to form an oxide layer on the semiconductor substrate, wherein during the oxidation treatment, the temperature of the processing liquid is maintained at approximately 65°C to approximately 85°C, and the oxidation treatment time is approximately 50 minutes to approximately 100 minutes.

In some embodiments, the oxidation process is included in a front-end-of-line (FEOL) process performed on a semiconductor substrate and/or in a back-end-of-line (BEOL) process performed on a semiconductor substrate.

In some embodiments, the front-end process includes forming trenches for a shallow trench isolation (STI) structure on the front side of a semiconductor substrate, and the oxidation treatment is performed after the trenches are formed to repair the surface of the semiconductor substrate having the trenches formed thereon.

In some embodiments, the back-end of the line (BOOL) process includes forming trenches for a deep trench isolation (DTI) structure on the back side of a semiconductor substrate. The oxidation treatment is performed after the trenches are formed to repair the surface of the semiconductor substrate having the trenches formed thereon.

In some embodiments, the treatment solution consists of water and hydrogen peroxide (H ₂ O ₂ ).

In some embodiments, the thickness of the oxide layer is greater than 8 Å.

In some embodiments, the process fluid is maintained at a temperature of about 65° C. to about 85° C. by passing through an ultrasonic oscillator at 50% to 100% of its maximum power, which is 1200 W to 2400 W.

In some embodiments, the process solution is maintained at a temperature of about 65° C. to about 85° C. by microwave or coil heating.

In some embodiments, when the processing liquid drops from a first level to a second level lower than the first level during the oxidation process, the method of forming a semiconductor device further includes injecting additional processing liquid into the processing tank to the first level of the processing tank.

In some embodiments, the process fluid is maintained at a temperature of about 65° C. to about 85° C. by additional injection of process fluid.

Based on the above, in the method for forming a semiconductor device, an oxidation treatment is performed by placing the semiconductor substrate in a treatment solution to form an oxide layer of a desired thickness on the damaged surface of the semiconductor substrate. In this way, damage to the semiconductor substrate caused by processes such as etching can be effectively repaired.

The present invention will be more fully described with reference to the drawings of the present embodiment. However, the present invention may be embodied in a variety of forms and should not be limited to the embodiments described herein. The thicknesses of layers and regions in the drawings are exaggerated for clarity. Identical or similar reference numbers denote identical or similar elements, and their individual descriptions will not be repeated in the following paragraphs.

It should be understood that when an element is referred to as being "on" or "connected to" another element, it can be directly on or connected to the other element, or intervening elements may be present. When an element is referred to as being "directly on" or "directly connected to" another element, there are no intervening elements. As used herein, "connected" can refer to physical and/or electrical connections, and "electrically connected" or "coupled" can mean the presence of other elements between two elements. As used herein, "electrically connected" can include physical connections (e.g., wired connections) and physical disconnections (e.g., wireless connections).

As used herein, "about," "approximately," or "substantially" includes the stated value and the average within an acceptable range of deviation from the specified value that can be determined by one of ordinary skill in the art, taking into account the measurement in question and the specific amount of error associated with the measurement (i.e., the limitations of the measurement system). For example, "about" can mean within one or more standard deviations of the stated value, or within ±30%, ±20%, ±10%, or ±5%. Furthermore, as used herein, "about," "approximately," or "substantially" can be used to select a more acceptable range of deviation or standard deviation depending on the optical property, etching property, or other property, and may not apply to all properties without using a single standard deviation.

The terms used herein are for describing exemplary embodiments only and are not intended to limit the present disclosure. In this context, unless otherwise indicated in the context, the singular includes the plural.

FIG1 is a flow chart of a method for forming a semiconductor device according to one embodiment of the present invention. FIG2A is a schematic cross-sectional view of a method for forming a semiconductor device according to one embodiment of the present invention. FIG2B is a schematic cross-sectional view of a method for forming a semiconductor device according to yet another embodiment of the present invention. FIG2C is a schematic cross-sectional view of a method for forming a semiconductor device according to yet another embodiment of the present invention. FIG2D is a schematic cross-sectional view of a method for forming a semiconductor device according to yet another embodiment of the present invention.

1 and any one of FIG. 2A to FIG. 2D , in this embodiment, a method for forming a semiconductor device may include the following steps.

First, the semiconductor substrate 100 is placed in the processing tank 10 (step S1).

The semiconductor substrate 100 may include a semiconductor substrate or a semiconductor-on-insulator (SOI) substrate. The semiconductor material in the semiconductor substrate or SOI substrate may include an elemental semiconductor, an alloy semiconductor, or a compound semiconductor. For example, an elemental semiconductor may include Si or Ge. An alloy semiconductor may include SiGe, SiGeC, or the like. A compound semiconductor may include SiC, a III-V semiconductor material, or a II-VI semiconductor material. The III-V semiconductor material may include GaN, GaP, GaAs, AlN, AlP, AlAs, InN, InP, InAs, GaNPs, GaNAs, GaPAs, AlNPs, AlNAs, AlPAs, InNPs, InNAs, InPAs, GaAlNPs, GaAlNAs, GaAlPAs, GaInNPs, GaInNAs, GaInPAs, InAlNPs, InAlNAs, or InAlPAs. Group II-VI semiconductor materials may include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnS e. CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe or HgZnSTe. The semiconductor material may be doped with a dopant of a first conductivity type or a dopant of a second conductivity type that is complementary to the first conductivity type. For example, the first conductivity type may be P-type and the second conductivity type may be N-type.

The processing tank 10 can be any processing tank suitable for placing the processing liquid 200. For example, the processing tank 10 can be made of a material that does not react with the processing liquid 200.

Next, a treatment liquid 200 is injected into the treatment tank 10 to a first level LV1, completely immersing the semiconductor substrate 100 in the treatment liquid 200 (step S2). In some embodiments, the treatment liquid 200 may _include an oxidizing agent and a solution. For example, if the semiconductor substrate 100 is a silicon substrate, the treatment liquid 200 may include water ( _H2O ) and hydrogen peroxide ( _H2O2 ), and the oxide layer subsequently formed in step S3 may be silicon oxide. In this embodiment, the treatment liquid 200 may be composed of water ( _H2O ) and _hydrogen peroxide ( _H2O2 ). The volume ratio of water to hydrogen peroxide in the treatment liquid 200 may be 1:15 or 1:100.

Then, the semiconductor substrate 100 is subjected to an oxidation treatment while stationary in the treatment solution 200 to form an oxide layer on the semiconductor substrate 100 (step S3). In this way, the surface of the semiconductor substrate 100 damaged by processes such as etching can be repaired by the oxide layer having a desired thickness formed thereon. In this embodiment, the thickness of the oxide layer is greater than 8 Å (e.g., 8.35 Å or 9.85 Å). In this embodiment, during the oxidation treatment, the temperature of the treatment solution 200 is maintained at approximately 65°C to approximately 85°C, and the oxidation treatment time is approximately 50 minutes to approximately 100 minutes. Since the semiconductor substrate 100 is oxidized in the treatment solution 200 in a static manner, the formed oxide layer can grow to the thickness required for the process (e.g., greater than 8 Å). This is different from the situation where the oxide layer formed in a circulating flow tank cannot reach the thickness required for the process (e.g., the thickness of the formed oxide layer is 5.98 Å, which is less than 8 Å) even at the same treatment temperature and treatment time.

The oxidation process may be included in the front-end-of-line (FEOL) process and/or the back-end-of-line (BEOL) process of the semiconductor substrate 100. Since the oxidation process is performed at a temperature of approximately 65°C to approximately 85°C, it is well suited for integration into the FEOL and/or BEOL processes without impacting the overall process thermal budget.

In some embodiments, the front-end process may include forming trenches for a shallow trench isolation (STI) structure on the front side of the semiconductor substrate 100. The oxidation treatment is performed after the trenches are formed to repair the surface of the semiconductor substrate 100 where the trenches are formed. For example, in the process of forming a complementary metal-oxide-semiconductor (CMOS), the front-end process includes forming an STI structure on the front side of a semiconductor substrate 100 to define an active region. The trenches used for the STI structure are formed by etching the semiconductor substrate 100. However, this process damages the surface of the semiconductor substrate 100. Therefore, before forming the oxide liner, the semiconductor substrate 100 can be subjected to an oxidation treatment by being statically placed in a treatment solution 200 to form an oxide layer on the semiconductor substrate 100 that can repair the damage.

In some embodiments, the back-end process may include forming trenches for a deep trench isolation (DTI) structure on the back side of the semiconductor substrate 100. The oxidation treatment is performed after the trenches are formed to repair the surface of the semiconductor substrate 100 where the trenches are formed. For example, in the process of forming a backside illumination (BSI) CMOS sensor, the back-end process includes forming a DTI structure on the back side of the semiconductor substrate 100 to define a pixel array. The trenches used for the DTI structure are formed by etching the semiconductor substrate 100. However, this process will cause damage to the surface of the semiconductor substrate 100. Therefore, before forming the high-k oxide layer, the semiconductor substrate 100 can be subjected to an oxidation treatment by being statically placed in a processing solution 200 to form an oxide layer on the semiconductor substrate 100 that can repair the damage.

In some embodiments, as shown in FIG2A , the processing liquid 200 may be maintained at a temperature of approximately 65° C. to approximately 85° C. by passing through an ultrasonic oscillator 20. In some embodiments, the power of the ultrasonic oscillator 20 may be 50% to 100% of the maximum power. In some embodiments, the maximum power may be 1200 W to 2400 W. In some embodiments, the processing liquid 200 may be maintained at a temperature above approximately 80° C. by passing through the ultrasonic oscillator 20.

In some embodiments, as shown in FIG2B or FIG2C , the temperature of the processing liquid 200 can be maintained at approximately 65°C to approximately 85°C by microwave or coil heating. For example, the temperature of the processing liquid 200 can be maintained at approximately 65°C to approximately 85°C by microwaves generated by a magnetron 22 (as shown in FIG2B ), or by a coil heater 24 (as shown in FIG2C ). In some embodiments, the temperature of the processing liquid 200 can be maintained at approximately 80°C or above by the magnetron 22 or coil heater 24. In some embodiments, the coil heater 24 can be immersed in the processing liquid 200 or can be located outside the processing tank 10, but the present invention is not limited thereto.

In some embodiments, as shown in FIG. 2B or 2D , when the processing liquid 200 drops from a first level LV1 to a second level LV2 lower than the first level LV1 during the oxidation treatment, the method for forming a semiconductor device may further include injecting additional processing liquid into the processing tank 10 to the first level LV1 of the processing tank 10. This can avoid the problem that the processing liquid 200 evaporates during the oxidation treatment (processing time is about 50 minutes to about 100 minutes) due to the high temperature used in the treatment (for example, 80° C. or higher), causing the liquid level to drop, thereby exposing the semiconductor substrate 100. In some embodiments, adding additional processing liquid at a desired temperature not only solves the problem of liquid level drop but also maintains the temperature of the processing liquid 200 at approximately 65°C to approximately 85°C, thereby eliminating the need for the aforementioned temperature maintenance equipment. In some embodiments, even if the liquid level does not drop, the temperature of the processing liquid 200 can be maintained at approximately 65°C to approximately 85°C by adding additional processing liquid at the desired temperature. Excess processing liquid 200 can overflow from the top of the processing tank 10 without disrupting the state in which the semiconductor substrate 100 is statically oxidized in the processing liquid 200.

In summary, in the method for forming a semiconductor device according to an embodiment of the present invention, an oxidation treatment is performed by placing a semiconductor substrate in a treatment solution to form an oxide layer of a desired thickness on the damaged surface of the semiconductor substrate. This effectively repairs damage to the semiconductor substrate caused by processes such as etching.

10: Processing tank 20: Ultrasonic oscillator 22: Magnetron 24: Coil heater 100: Semiconductor substrate 200: Processing liquid LV1: First level LV2: Second level S1, S2, S3: Steps

Figure 1 is a flow chart of a method for forming a semiconductor device according to one embodiment of the present invention. Figure 2A is a schematic cross-sectional view of a method for forming a semiconductor device according to one embodiment of the present invention. Figure 2B is a schematic cross-sectional view of a method for forming a semiconductor device according to yet another embodiment of the present invention. Figure 2C is a schematic cross-sectional view of a method for forming a semiconductor device according to yet another embodiment of the present invention. Figure 2D is a schematic cross-sectional view of a method for forming a semiconductor device according to yet another embodiment of the present invention.

S1, S2, S3: Steps

Claims (9)

A method for forming a semiconductor device includes: placing a semiconductor substrate in a processing tank; injecting a processing liquid into the processing tank to a first level of the processing tank so that the semiconductor substrate is completely immersed in the processing liquid; and performing an oxidation treatment on the semiconductor substrate while stationary in the processing liquid to form an oxide layer on the semiconductor substrate, wherein during the oxidation treatment, the temperature of the processing liquid is maintained at approximately 65° C. to approximately 85° C., and the oxidation treatment lasts for approximately 50 minutes to approximately 100 minutes, wherein the oxidation treatment is included in a front-end-of-line (FEOL) process and/or in a back-end-of-line (BEOL) process performed on the semiconductor substrate. A method as described in claim 1, wherein the front-end process includes forming a trench for a shallow trench isolation (STI) structure on the front side of the semiconductor substrate, and the oxidation treatment is performed after the trench is formed to repair the surface of the semiconductor substrate where the trench is formed. A method as described in claim 1, wherein the back-end process includes forming a trench for a deep trench isolation (DTI) structure on the back side of the semiconductor substrate, and the oxidation treatment is performed after the formation of the trench to repair the surface of the semiconductor substrate where the trench is formed. The method of claim 1, wherein the treatment solution consists of water and hydrogen peroxide (H ₂ O ₂ ). The method of claim 1, wherein the thickness of the oxide layer is greater than 8 Å. The method of claim 1, wherein the treatment liquid is passed through an ultrasonic oscillator to maintain the temperature at about 65°C to about 85°C, the power of the ultrasonic oscillator is 50% to 100% of the maximum power, and the maximum power is 1200 W to 2400 W. The method of claim 1 , wherein the treatment solution is maintained at a temperature of about 65° C. to about 85° C. by microwave or coil heating. A method as described in claim 1, wherein when the treatment liquid drops from the first level to a second level lower than the first level during the oxidation treatment, the method further includes injecting additional treatment liquid into the treatment tank to the first level of the treatment tank. The method of claim 8, wherein the treatment fluid is maintained at a temperature of about 65°C to about 85°C by additional injection of the treatment fluid.