JP4910680B2 - Composition for cleaning semiconductor manufacturing apparatus and cleaning method using the same - Google Patents

Description

  The present invention relates to a composition for cleaning a semiconductor manufacturing apparatus and a cleaning method using the same, and in particular, cleaning of a shield in a CVD or sputtering apparatus to which metal titanium, titanium oxide, titanium nitride, metal copper, copper oxide, etc. are attached. The present invention relates to a composition for cleaning and a cleaning method using the same.

  In the manufacturing process of semiconductor devices, metals such as titanium and copper are formed on a wafer using a sputtering apparatus or the like. When these metals are formed on a wafer, not only on the wafer but also on the semiconductor. It also adheres to the device manufacturing device.

  Usually, a CVD or sputtering apparatus is provided with a shield (a deposition plate) made of aluminum or stainless steel, and a metal film formed on the wafer also adheres to this shield. In the process of processing many wafers, the thickness of the metal deposited on the shield increases, and may reach an unacceptable thickness for stable operation of the apparatus. Therefore, it is necessary to periodically remove the metal adhering to the shield.

  Incidentally, methods for removing metals such as titanium and copper are generally well known. Cleaning with hydrofluoric acid is known as a method for removing titanium oxide on a wafer in the process of manufacturing a semiconductor device (see, for example, Patent Document 1). Although this hydrofluoric acid exhibits excellent titanium dissolution and removal properties, it is very damaging to aluminum and stainless steel and cannot be used when the shield material is aluminum or stainless steel.

  Similarly, hydrofluoric acid and nitric acid-based etching solutions are well known for removing metallic titanium (see, for example, Patent Document 2). As a result, the metal titanium could not be removed with high selectivity.

  On the other hand, a patent for etching a group 3/5 group semiconductor material such as GaP, AlAs, and GaAs with an etching solution composed of fluorine ions, phosphoric acid and hydrogen peroxide in manufacturing a semiconductor device is also disclosed. (For example, refer to Patent Document 3). In addition, in a semiconductor device manufacturing process, a patent for deburring and etching with a similar composition liquid in a pretreatment for solder plating of a lead frame is also disclosed (for example, see Patent Document 4). This is characterized in that the surface treatment of the lead frame mainly composed of copper or iron on the semiconductor device is performed simultaneously with deburring. However, none of these patents are intended for etching semiconductor devices and are not used for cleaning an apparatus for manufacturing semiconductor devices. Further, these patents do not describe any effect of suppressing damage to specific metals such as aluminum and stainless steel.

  Furthermore, as a titanium etching method that simultaneously removes the surface scale and smoothes the surface of titanium metal, an etching solution comprising hydrogen peroxide, fluoride, phosphoric acid, and a fluorine-based surfactant is disclosed (for example, Patent Document 5). reference). However, when the weight ratio of hydrogen peroxide to fluoride fluorine is 3 or less, titanium has good solubility, but when aluminum or stainless steel is present, the damage to these is significant and the material of the shield Cannot be used when aluminum or stainless steel is used.

  Therefore, the conventionally known composition liquid used for semiconductor device etching selects titanium, copper, etc. attached to the shield without damaging the shield material such as aluminum or stainless steel when cleaning the semiconductor manufacturing equipment. It was difficult to remove and clean.

JP-A-2-44721 JP-A-7-118842 U.S. Pat. No. 4,353,779 JP 9-31669 A JP 2004-43850 A

  The object of the present invention is to selectively remove deposits such as metal titanium, titanium oxide, titanium nitride, metal copper, and copper oxide attached to the shield without damaging the shield materials such as aluminum, aluminum alloy, and stainless steel. An object of the present invention is to provide a cleaning composition and a cleaning method using the same.

  As a result of intensive studies on the cleaning of the shielding material to which titanium, copper or the like is attached, the present inventors have found that at least one fluorine compound selected from the group consisting of sodium fluoride, potassium fluoride, lithium fluoride and ammonium fluoride, A specific concentration composition comprising phosphoric acid and / or phosphate, hydrogen peroxide, and hydrofluoric acid selectively removes titanium, copper, etc. without damaging aluminum, aluminum alloys, stainless steel, etc. As a result, the present invention has been completed.

  The present invention is described in detail below.

  The cleaning composition in the present invention comprises a specific fluorine compound, phosphoric acid and / or phosphate, hydrogen peroxide, and hydrofluoric acid.

  In the cleaning composition of the present invention, the specific fluorine compound is at least one selected from the group consisting of sodium fluoride, potassium fluoride, lithium fluoride, and ammonium fluoride. Other fluorine compounds may be used, but they are not industrially advantageous because they have low solubility in water or are expensive. Among sodium fluoride, potassium fluoride, lithium fluoride, and ammonium fluoride, sodium fluoride is preferable because it is less damaging to aluminum and is inexpensive and easily available.

  The phosphoric acid in the cleaning composition of the present invention is at least one selected from the group consisting of orthophosphoric acid, metaphosphoric acid, polyphosphoric acid and salts thereof.

  As phosphoric acid used in the present invention, there are a third salt of a normal salt, a first salt of a dihydrogen salt, and a second salt of a monohydrogen salt, but any water-soluble salt can be used without any problem.

  The hydrogen peroxide in the cleaning composition of the present invention is not particularly limited, and those commercially available can be used.

  In the cleaning composition of the present invention, hydrofluoric acid can be further used. By adding hydrofluoric acid, the amount of fluorine compound such as sodium fluoride used can be reduced, and the reduction in removal rate can be suppressed. However, when hydrofluoric acid is not used in combination with a fluorine compound, damage to aluminum as a shield base material is increased. As the hydrofluoric acid, a high-purity one that is commercially available for electronic materials can be used.

  In the cleaning composition of the present invention, the weight ratio of hydrogen peroxide to the amount of fluorine in the fluorine component in the system (hydrogen peroxide / fluorine) must be 4 or more. When this ratio is less than 4, damage to aluminum increases.

  The concentration of the specific fluorine compound, phosphoric acid and / or phosphate, and hydrogen peroxide relative to the total amount of the cleaning composition is 0.1 to 10% by weight of the fluorine compound and 1 to 1 of phosphoric acid and / or phosphate. 50% by weight, preferably 0.1 to 5% by weight of a specific fluorine compound, and 20 to 40% by weight of phosphoric acid and / or phosphate. If the specific fluorine compound is less than 0.1% by weight, the removal rate of the deposit is so slow that it is not industrial, and if the specific fluorine compound exceeds 10% by weight, the damage to aluminum is increased, which is not preferable. Also, if the phosphoric acid and / or phosphate is less than 1% by weight, the removal rate of the deposits is so slow that it is not industrial, and if the phosphoric acid and / or phosphate exceeds 50% by weight, the damage to the aluminum is large. Therefore, it is not preferable. The amount of hydrogen peroxide is 0.5 to 35% by weight, preferably 2 to 20% by weight. If the amount is less than 0.5% by weight, the damage to the aluminum becomes large. If the amount exceeds 35% by weight, there is a risk of explosion, which is not preferable for industrial use. Hydrofluoric acid is not particularly limited because it depends on the concentration of the fluorine compound, but it is preferably 5% by weight or less depending on the amount of the fluorine compound used. Furthermore, 0.1 to 3 weight% is preferable.

  In the cleaning composition of the present invention, the remainder other than the specific fluorine compound, phosphoric acid and / or phosphate, hydrogen peroxide, and hydrofluoric acid is water.

  An anticorrosive agent for a substrate such as aluminum can also be added to the cleaning composition of the present invention.

  The cleaning composition of the present invention is preferably used at 0 to 100 ° C. If it is less than 0 ° C., the removal rate of the deposits is so slow that it is not practical, and if it exceeds 100 ° C., the concentration fluctuation of the cleaning composition is large and not industrial.

  Deposits that can be removed by the cleaning composition of the present invention are metal titanium, titanium oxide, titanium nitride, metal copper, copper oxide, etc., and any of these can be easily removed by the cleaning composition of the present invention. it can.

  The cleaning composition of the present invention can be used to remove titanium, copper, and the like attached to a shield based on aluminum, aluminum alloy, stainless steel, or the like.

  The composition for cleaning a semiconductor manufacturing apparatus of the present invention removes attached metal titanium, titanium oxide, titanium nitride, metal copper, copper oxide and the like without damaging a base material such as aluminum, aluminum alloy, and stainless steel. Can do.

Hereinafter, although the washing | cleaning method of this invention is demonstrated by an Example, this invention is not limited to these. In order to simplify the notation, the following abbreviations were used.
NaF: sodium fluoride HF: hydrofluoric acid PA: phosphoric acid SHP: sodium dihydrogen phosphate HPO: hydrogen peroxide Examples 1-4, Comparative Examples 1-6
Titanium or copper was sputtered to a thickness of 0.1 mm on aluminum and stainless steel (SUS316L), respectively. This was immersed in the cleaning composition described in Table 1, and the time for completely removing titanium or copper was measured. The results are shown in Table 1.

  In addition, the case where titanium or copper was completely removed within 6 hours was marked as ◯, and the case where it exceeded 6 hours was marked as x.

  Further, at that time, the case where the damage of aluminum or stainless steel was 0.01 mm or less was evaluated as ◯, and the case where the damage exceeded 0.01 mm was evaluated as ×.

Claims (4)

0.1 to 10% by weight of at least one fluorine compound selected from the group consisting of sodium fluoride, potassium fluoride and lithium fluoride, 1 to 50% by weight of phosphoric acid and / or phosphate, and hydrogen peroxide. 0.5 to 35% by weight and 5% by weight or less of hydrofluoric acid, the balance being water, and the weight ratio of hydrogen peroxide to the amount of fluorine in the fluorine component in the system (hydrogen peroxide / fluorine) A composition for cleaning a semiconductor manufacturing apparatus, wherein the composition is 4 or more. The composition for cleaning a semiconductor manufacturing apparatus according to claim 1, wherein the fluorine compound is sodium fluoride. Phosphoric acid, orthophosphoric acid, metaphosphoric acid, a semiconductor manufacturing apparatus cleaning composition according to claim 1 or 2, characterized in that at least one selected from the group consisting of polyphosphoric acid. The method for cleaning a semiconductor manufacturing apparatus according to any one of claims 1 to 3 , wherein at least one kind of deposits made of metal titanium, titanium oxide, titanium nitride, metal copper, and copper oxide is adhered. A cleaning method for a semiconductor manufacturing apparatus, wherein the cleaning is performed using a composition.