CN110634730A - Method for reworking gate oxide interruption after groove Schottky polysilicon deposition - Google Patents

Abstract

A gate oxide interruption rework method after groove Schottky polysilicon deposition. Relates to the technical field of manufacturing of discrete devices in the semiconductor manufacturing technology, in particular to a gate oxide interruption reworking method after groove Schottky polycrystalline silicon is deposited. The gate oxide interruption reworking method after the groove Schottky polycrystalline silicon is deposited is provided, the influence on the gate oxide is small, and a good Poly reworking effect can be achieved. The invention measures the thickness T of the Poly layer of the product to be reworked in advance₁And the corresponding time t required for etching₁=T₁And/5000, effectively removing the Poly layer by using silicon etching solution (HNO 3+ HF + HAc + H2O) + nitric acid (HNO 3), and effectively removing the Poly by using mixed solution with a certain mass ratio, and simultaneously reducing the influence on the gate oxide layer, thereby achieving a good Poly reworking effect. The method has the characteristics of less influence on the gate oxide, good Poly reworking effect and the like.

Description

Method for reworking gate oxide interruption after groove Schottky polysilicon deposition

Technical Field

The invention relates to the technical field of discrete device manufacturing in the semiconductor manufacturing technology, in particular to a gate oxide interruption reworking method after groove Schottky polycrystalline silicon is deposited.

Background

In the manufacturing process of the trench schottky product, the gate oxide deposition and the Poly deposition are time-consuming and important processes, and when the process is interrupted due to other abnormal reasons in the manufacturing process, the gate oxide is seriously damaged when the common oxidant is used for removing the Poly, so the product can only be discarded and cannot be reworked.

Disclosure of Invention

Aiming at the problems, the invention provides a gate oxide interruption reworking method after groove Schottky polycrystalline silicon deposition, which has less influence on gate oxide and can achieve good Poly reworking effect.

The technical scheme of the invention is as follows: a gate oxide interruption rework method after groove Schottky polysilicon deposition comprises the following steps:

1) testing the thickness T1 of the polysilicon layer of the product to be reworked by using measuring equipment;

2) calculating the corresponding time T1= T1/5000 needing to be corroded according to the corrosion speed of the corrosion liquid;

3) putting the product to be reworked into an acid tank containing the mixed solution, taking out the product after t1 time of reaction, and cleaning the residual acid solution on the surface;

4) measuring the residual Poly thickness T2 on the surface of the product cleaned in the step 3);

5) adding rot according to the residual thickness T2, wherein the rot adding time is T2= T2/5000;

6) and 5) after the Poly layer is corroded, removing residual gate oxide according to the thickness measured by the gate oxide layer by using BOE corrosive liquid.

The mixed solution in the step 3) is a mixed solution of 68% HNO3, 49% HF, 98% HAc and H2O.

The volume ratio of 68 percent HNO3, 49 percent HF, 98 percent HAc and H2O is 8:1:2:1

The BOE corrosive liquid in the step 6) comprises 49% of HF aqueous solution and 40% of NH4F aqueous solution.

The volume ratio of the 49% HF aqueous solution to the 40% NH4F aqueous solution is 1: 20.

the invention measures the thickness T of the Poly layer of the product to be reworked in advance₁ And the corresponding time t required for etching₁=T₁And/5000, effectively removing the Poly layer by using silicon etching solution (HNO 3+ HF + HAc + H2O) + nitric acid (HNO 3), and effectively removing the Poly by using mixed solution with a certain mass ratio, and simultaneously reducing the influence on the gate oxide layer, thereby achieving a good Poly reworking effect. The method has the characteristics of less influence on the gate oxide, good Poly reworking effect and the like.

Drawings

Figure 1 is a schematic diagram of the structure of a completed gate oxide deposition product,

FIG. 2 is a schematic view of a completed Poly deposition layer,

in the figure, 1 is a gate oxide deposition layer, and 2 is a Poly layer.

Detailed Description

The invention is shown in fig. 1-2, the object of the invention: the method comprises the following steps of removing the Poly layer 2 by using silicon etching solution (HNO 3+ HF + HAc + H2O) + nitric acid (HNO 3), wherein the etching speed of the Poly layer is about 5000A/min, the etching speed of Oxide is about 100A/min, the mixed solution can effectively remove the Poly layer, the influence on the gate Oxide deposition layer 1 is small, and a good Poly rework effect can be achieved.

A gate oxide interruption rework method after groove Schottky polysilicon deposition comprises the following steps:

1) and testing the thickness T of the layer of the polysilicon (Poly in the case) of the product to be reworked by using the measuring equipment₁；

2) Calculating the corresponding time t required to be corroded according to the corrosion speed of the corrosion liquid₁=T₁/5000 (unit: min);

3) putting the product to be reworked into an acid tank containing the mixed solution, and reacting t₁After the time, taking out the product, and cleaning the residual acid liquor on the surface; washing with pure water to remove residual acid solution

4) Measuring the residual Poly thickness T2 on the surface of the product cleaned in the step 3);

5) adding rot according to the residual thickness T2, wherein the rot adding time is T2= T2/5000; the corrosion adding process is to put the cleaned product into the acid solution tank again for treatment;

6) and 5) after the Poly layer is corroded, removing residual gate oxide by using BOE corrosive liquid according to the thickness measured by the actual gate oxide layer. Chemical equation of reaction: SiO 2₂+6HF=H₂SiF₆+2H₂O

The mixed solution in the step 3) is a mixed solution of 68% HNO3, 49% HF, 98% HAc and H2O.

The volume ratio of 68 percent HNO3, 49 percent HF, 98 percent HAc and H2O is 8:1:2:1

The BOE corrosive liquid in the step 6) comprises 49% of HF aqueous solution and 40% of NH4F aqueous solution.

The BOE corrosive liquid is as follows: buffered oxide etch, semiconductor common chemistry, here 49% aqueous HF: 40% NH4F aqueous solution = 1: 20 (volume ratio);

the volume ratio of the 49% HF aqueous solution to the 40% NH4F aqueous solution is 1: 20.

the reaction equation is as follows: 1. 3Si +18HF +4HNO₃=3H₂SiF₆+4NO↑+8H₂O

2、SiO₂+6HF=H₂SiF₆+2H₂O

The disclosure of the present application also includes the following points:

(1) the drawings of the embodiments disclosed herein only relate to the structures related to the embodiments disclosed herein, and other structures can refer to general designs;

(2) in case of conflict, the embodiments and features of the embodiments disclosed in this application can be combined with each other to arrive at new embodiments;

the above embodiments are only embodiments disclosed in the present disclosure, but the scope of the disclosure is not limited thereto, and the scope of the disclosure should be determined by the scope of the claims.

Claims (5)

1. A gate oxide interruption rework method after groove Schottky polysilicon deposition is characterized by comprising the following steps:

1) testing the thickness T1 of the polysilicon layer of the product to be reworked by using measuring equipment;

2) calculating the corresponding time T1= T1/5000 needing to be corroded according to the corrosion speed of the corrosion liquid;

3) putting the product to be reworked into an acid tank containing the mixed solution, taking out the product after t1 time of reaction, and cleaning the residual acid solution on the surface;

4) measuring the residual Poly thickness T2 on the surface of the product cleaned in the step 3);

5) adding rot according to the residual thickness T2, wherein the rot adding time is T2= T2/5000;

6) and 5) after the Poly layer is corroded, removing residual gate oxide according to the thickness measured by the gate oxide layer by using BOE corrosive liquid.

2. The method of claim 1, wherein the mixed solution in step 3) is a mixed solution of 68% HNO3, 49% HF, 98% HAc and H2O.

3. The method of claim 2, wherein a volume ratio of 68% HNO3, 49% HF, 98% HAc, and H2O is 8:1:2: 1.

4. The method as claimed in claim 2, wherein said BOE etchant in step 6) comprises 49% HF solution and 40% NH4F solution.

5. The method of claim 4, wherein a volume ratio of the 49% HF aqueous solution to the 40% NH4F aqueous solution is 1: 20.

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