JP2007266467A - Device and method for manufacturing semiconductor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor manufacturing method and a semiconductor manufacturing device for restraining the occurrence of defects on a wafer, and improving the yield of a semiconductor device in SFM treatment. <P>SOLUTION: The semiconductor manufacturing method includes: a process for selectively removing an object to be removed in the wafer by a mixed liquid 1 of sulfuric acid, HF, and H<SB>2</SB>O; a process for substituting the mixed liquid 1 remaining in the wafer by a diluted HF solution 2 or a high-concentration H<SB>2</SB>SO<SB>4</SB>liquid; and a process for removing the diluted HF solution 2 or the high-concentration H<SB>2</SB>SO<SB>4</SB>liquid remaining on the wafer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a semiconductor manufacturing method and a semiconductor manufacturing apparatus that perform chemical processing such as cleaning processing of a semiconductor wafer.

2. Description of the Related Art In recent years, sulfuric acid / HF mixed solution wet processing (hereinafter referred to as SFM processing) has been used for peeling of BSG (Boron doped Silicate Glass) used as a hard mask, for example, in semiconductor manufacturing processes. This SFM process can stably realize a high selection ratio with a thermal oxide film even in a large-diameter wafer by controlling the dissociation of HF in dilute sulfuric acid (H ₂ SO ₄ ) of H ₂ O. Process (see, for example, Patent Document 1).

  Like this SFM treatment, in the chemical treatment with sulfuric acid solution, the sulfuric acid solution remains on the wafer due to the high viscosity of sulfuric acid, so after the chemical treatment, the sulfuric acid solution is removed by the overflow process by pure water rinse treatment. is doing.

However, there is a problem that a defect due to a residue occurs on the wafer after the SFM process and the yield of the semiconductor device is lowered.
JP 2002-246378 A ([Claim 1], [0109], etc.)

  An object of the present invention is to provide a semiconductor manufacturing method and a semiconductor manufacturing apparatus capable of suppressing the occurrence of defects on a wafer and improving the yield of a semiconductor device in SFM processing.

According to one embodiment of the present invention, a step of selectively removing an object to be removed generated on a wafer using a mixed solution of sulfuric acid, HF, and H ₂ O and a residue on the wafer using a diluted HF solution There is provided a semiconductor manufacturing method comprising a step of replacing a mixed solution to be removed and a step of removing a diluted HF solution remaining on a wafer.

In addition, according to one embodiment of the present invention, a step of selectively removing an object to be removed generated on a wafer using a mixed solution of sulfuric acid, HF, and H ₂ O, and a concentration of H ₂ O from the mixed solution There is provided a semiconductor manufacturing method comprising a step of replacing a mixed solution remaining on a wafer with a low sulfuric acid solution and a step of removing the sulfuric acid solution remaining on the wafer.

In addition, according to one embodiment of the present invention, a mixed liquid of sulfuric acid, HF, and H ₂ O is introduced, and a wafer is put into the mixed liquid to selectively remove an object to be removed generated on the wafer. A first treatment tank, a second treatment tank for introducing a dilute HF solution, introducing a wafer into the dilute HF solution, and replacing the liquid mixture remaining on the wafer, and a rinse liquid are introduced. There is provided a semiconductor manufacturing apparatus comprising a third processing tank for putting a wafer into a rinsing liquid and removing a diluted HF solution remaining on the wafer.

In addition, according to one embodiment of the present invention, a mixed liquid of sulfuric acid, HF, and H ₂ O is introduced, and a wafer is put into the mixed liquid to selectively remove an object to be removed generated on the wafer. A first treatment tank, and a _second treatment tank for introducing a sulfuric acid solution having a H ₂ O concentration lower than that of the mixed solution into the wafer and replacing the mixed solution remaining on the wafer There is provided a semiconductor manufacturing apparatus comprising a third processing tank for introducing a rinsing liquid and putting a wafer into the rinsing liquid to remove a sulfuric acid liquid remaining on the wafer.

  According to one embodiment of the present invention, it is possible to suppress the occurrence of defects on the wafer and improve the yield of the semiconductor device in the SFM process.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 shows the configuration of the semiconductor manufacturing apparatus of this embodiment. As shown in the figure, a first treatment tank 11 into which a mixed liquid of sulfuric acid, HF, and H ₂ O (hereinafter referred to as SFM mixed liquid) 1 is introduced, and a second treatment tank into which a diluted HF solution 2 is introduced. 12 and three wet processing tanks of a third processing tank 13 into which the post-treatment chemical solution 3 is introduced.

A series of wet processing is performed as follows using a semiconductor manufacturing apparatus having such a processing tank. First, an SFM mixed solution 1 composed of, for example, sulfuric acid: 96 wt%, HF: 1 wt%, and H ₂ O: 3 wt% is prepared in advance and supplied to the first treatment tank 11. Then, for example, one lot of wafers W on which a BSG hard mask is formed are carried in the holder H into the first processing tank 11 to which the mixed liquid 1 is supplied, and immersed in the mixed liquid 1 to perform SFM processing. I do.

This SFM process is a circulation process, and the SFM mixture 1 is circulated and supplied through a filter (not shown). Meanwhile, since the HF / H ₂ O concentration required for etching is stably controlled, a considerable number of treatments are possible until the SiO ₂ concentration caused by the removed BSG reaches the saturation concentration. It is repeatedly used until a certain liquid exchange state is reached. Therefore, an oxide film residue such as BSG is accumulated in the SFM liquid mixture 1.

  By selectively removing the BSG hard mask generated on the wafer W by such SFM processing, the wafer W is unloaded from the first processing tank 11. At the time of unloading, the wafer W is pulled up from the SFM liquid mixture 1, but at this time, the SFM liquid mixture runs out and remains on the wafer W. Note that the amount of residual liquid that has permeated inside varies depending on the uneven shape (such as the aspect ratio) on the wafer W.

At this time, the remaining SFM mixed solution contains a large amount of oxide film residue as described above, and if this is treated with pure water rinsing as in the prior art, it is exposed to a washing environment in which a large amount of H ₂ O exists. As a result, the inventors have made it clear that a sudden phase change occurs and the crystallization (precipitation) of the residue proceeds rapidly. Defects caused by deposition are affected by the degree of adsorption on the wafer, but it is difficult to remove them completely by contacted physical cleaning such as MHz (ultrasonic wave) processing, which reduces the yield of semiconductor devices. End up.

  Therefore, in order to suppress the precipitation reaction, a substitution process using a diluted HF solution (hereinafter referred to as HF rinsing process) is performed. The HF solution 2 having a concentration of 0.1 wt% is prepared in advance and supplied to the second treatment tank 12. Then, one lot of wafers subjected to SFM processing is carried into the second processing tank 12 to which the HF solution 2 is supplied, and is immersed in the diluted HF solution 2 to perform HF rinsing processing.

  As shown in FIG. 2, the HF rinsing process replaces the SFM mixed solution 1 ′ remaining on the wafer W with the HF solution, but the SFM mixed solution that has penetrated to the inside of the concavo-convex shape having a high aspect ratio It is necessary to replace with a sufficiently dilute HF solution. FIG. 3 shows the relationship between the HF rinse treatment time and the number of deposition defects. As shown in the figure, as the processing time increases, the substitution proceeds, so the number of precipitation defects decreases and becomes zero in 180 seconds. On the other hand, if the length is too long, the thermal oxide film is etched by HF and recedes, so that the receding amount of the thermal oxide film needs to be controlled to 5 A or less. Accordingly, the processing time is preferably 60 to 600 seconds. More preferably, it is 180 to 570 seconds. After the SFM mixed solution 1 ′ remaining on the wafer W is sufficiently replaced with the HF solution by such HF rinsing processing, rinsing processing with pure water is performed, and the wafer W is unloaded from the second processing bath 12.

After HF rinsing, a post-treatment such as an alkaline overwater treatment is performed to remove defects. A pretreatment chemical solution 3 such as SC1 (ammonia hydrogen peroxide) prepared in advance is supplied to the third treatment tank. Then, one lot of wafers W subjected to the HF rinsing process are carried into the third processing tank 13 to which the post-processing chemical solution 3 is supplied, and post-processing is performed by being immersed in the post-processing chemical solution 3 and overflowing. Since the SFM mixed solution has been sufficiently replaced by the previous HF rinsing process and the residue concentration on the wafer has been reduced, a large amount of H at the time of pure water rinsing after HF rinsing and pure water rinsing after alkaline overwater. _Even when exposed to a water-washing environment in which ₂ O is present, no precipitation reaction occurs and the occurrence of precipitation defects can be suppressed. Accordingly, it is possible to improve the yield of the semiconductor device formed through the element formation step and the separation step.

  In this embodiment, the dilute HF solution has a concentration of 0.1 wt%, but it is preferably 0.1 wt% or less in order to suppress etching of the thermal oxide film. On the other hand, if the concentration is too low, the equilibrium shifts to the precipitation reaction side, so 0.01 wt% or more is preferable.

(Embodiment 2)
FIG. 4 shows the configuration of the semiconductor manufacturing apparatus of this embodiment. As shown in the figure, a first treatment tank 21 into which the SFM mixed liquid 1 is introduced, a second treatment tank 22 into which a high concentration H ₂ SO ₄ liquid 4 having a higher sulfuric acid concentration than the SFM mixed liquid is introduced, It comprises four wet processing tanks, a third processing tank 23 into which pure water 5 is introduced and a fourth processing tank 24 into which post-treatment chemical solution 3 is introduced.

A series of wet processing is performed as follows using a semiconductor manufacturing apparatus having such a processing tank. First, as in the first embodiment, an SFM mixed solution 1 composed of sulfuric acid: 96 wt%, HF: 1 wt%, and H ₂ O: 3 wt% is prepared and subjected to SFM treatment. Then, in order to suppress the precipitation reaction due to the remaining SFM mixed solution, a substitution treatment (hereinafter referred to as a high concentration H ₂ SO ₄ treatment) with 98 wt% or more of the high concentration H ₂ SO ₄ solution 4 is performed. The high-concentration H ₂ SO ₄ liquid 4 is adjusted in advance and supplied to the second treatment tank 22. Then, the second processing tank 22 to the high-concentration _H 2 SO ₄ solution 4 is supplied, the wafer W of one lot that is SFM processing carried and held in the holder H, the high-concentration _H 2 SO ₄ solution 4 It is immersed in high concentration H ₂ SO ₄ treatment.

As shown in FIG. 5, the high concentration H ₂ SO ₄ treatment replaces the SFM mixed liquid 1 ′ remaining on the wafer W with the high concentration H ₂ SO ₄ liquid 4, and has an uneven shape with a high aspect ratio. It is necessary to replace the SFM mixed solution that has penetrated to the inside with a sufficiently high concentration H ₂ SO ₄ solution. After the high-concentration H ₂ SO ₄ treatment replaces the SFM mixed solution 1 ′ remaining on the wafer W with the high-concentration H ₂ SO ₄ solution 4, the wafer W is unloaded from the second treatment tank 22.

Next, pure water rinse treatment is performed to remove the high concentration H ₂ SO ₄ liquid 4. Pure water is supplied to the third processing tank, and one lot of wafers W that have been subjected to high-concentration H ₂ SO ₄ is carried into the third processing tank 23 to which pure water has been supplied, and immersed in the pure water 5. The pure water rinse process is performed by overflowing. Since the SFM mixed solution has been sufficiently replaced by the previous high concentration H ₂ SO ₄ treatment and the residue concentration on the wafer has been reduced, precipitation occurs even when exposed to a water washing environment where a large amount of H ₂ O exists. Reaction does not occur, and the occurrence of precipitation defects can be suppressed.

Further, post-treatment such as alkaline overwater treatment for defect removal is performed. Similarly to the first embodiment, a post-treatment chemical solution 3 such as SC1 (ammonia hydrogen peroxide) prepared in advance is supplied to the fourth treatment tank. Then, a lot of wafers W that have been treated with high-concentration H ₂ SO ₄ are carried into the fourth treatment tank 24 to which the post-treatment chemical solution 3 has been supplied, and are immersed in the post-treatment chemical solution 3 to overflow. Process. The SFM mixed solution is sufficiently replaced by the previous high concentration H ₂ SO ₄ rinsing treatment, and the residue concentration on the wafer is reduced. Therefore, even when exposed to a water washing environment where a large amount of H ₂ O exists, The precipitation reaction does not occur, and the occurrence of precipitation defects can be suppressed. Accordingly, it is possible to improve the yield of the semiconductor device formed through the element formation step and the separation step.

In this embodiment, a high-concentration H ₂ SO ₄ liquid having a concentration of 98 wt% or more is used, but it is sufficient that the concentration is higher than the sulfuric acid concentration (96 wt% in the present embodiment) of the SFM mixed solution.

In these embodiments, the SFM mixed solution, sulfuric _{acid: 96wt%, HF: 1wt%} , H 2 O: was prepared as a 3 wt%, it is not particularly defined, _{H 2} O is less 5 wt% and It suffices if it is prepared as follows.

  In addition, this invention is not limited to embodiment mentioned above. Various other modifications can be made without departing from the scope of the invention.

FIG. 6 illustrates a structure of a semiconductor manufacturing apparatus of one embodiment of the present invention. The figure which shows the concept of the HF rinse process in 1 aspect of this invention. The figure which shows the relationship between the HF rinse process time in 1 aspect of this invention, and the number of precipitation defects. FIG. 6 illustrates a structure of a semiconductor manufacturing apparatus of one embodiment of the present invention. Diagram showing the concept of a high-concentration H ₂ SO ₄ treatment in one aspect of the present invention.

Explanation of symbols

1 ... SFM mixed solution, 2 ... dilute HF solution, 3 ... post-treatment agent, 4 ... high concentration _H 2 _SO 4, 11,12,13,21,22,23,24 ... processing tank

Claims (5)

A step of selectively removing an object to be removed generated on a wafer using a mixed solution of sulfuric acid, HF, and H ₂ O;
Substituting the mixed liquid remaining on the wafer with a diluted HF solution;
A method of manufacturing a semiconductor, comprising a step of removing the diluted HF solution remaining on the wafer.   The semiconductor manufacturing method according to claim 1, wherein the concentration of the diluted HF solution is 0.01 to 0.1 wt%. A step of selectively removing an object to be removed generated on a wafer using a mixed solution of sulfuric acid, HF, and H ₂ O;
Using a sulfuric acid solution having a lower H ₂ O concentration than the mixed solution to replace the mixed solution remaining on the wafer;
A method of manufacturing a semiconductor, comprising a step of removing the sulfuric acid solution remaining on the wafer. A first treatment tank for introducing a mixed solution of sulfuric acid, HF, and H ₂ O, for introducing a wafer into the mixed solution, and selectively removing an object to be removed generated on the wafer;
A second treatment tank for introducing a dilute HF solution, and for introducing the wafer into the dilute HF solution to replace the mixed solution remaining on the wafer;
A semiconductor manufacturing apparatus comprising: a third processing tank for introducing a rinsing liquid into the rinsing liquid and removing the diluted HF solution remaining on the wafer. A first treatment tank for introducing a mixed solution of sulfuric acid, HF, and H ₂ O, for introducing a wafer into the mixed solution, and selectively removing an object to be removed generated on the wafer;
A second treatment tank for introducing a sulfuric acid solution having a H ₂ O concentration lower than that of the mixed solution, and for replacing the mixed solution remaining in the wafer by introducing the wafer into the sulfuric acid solution;
A semiconductor manufacturing apparatus comprising a third processing tank for introducing a rinsing liquid, putting a wafer into the rinsing liquid, and removing the sulfuric acid solution remaining on the wafer.

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