Patent ID: 8038798

Claim:
A method of cleaning a substrate, said method including sequentially performing a liquid chemical process using a liquid chemical and a rinsing process using deionized water upon a substrate in a single processing bath, said method comprising the steps of: a) setting a first resistivity threshold value; b) setting a second resistivity threshold value which is larger than said first resistivity threshold value; c) performing a first liquid chemical process using a first liquid chemical in said processing bath, wherein the first liquid chemical is hydrofluoric acid; d) supplying deionized water into said processing bath to force the first liquid chemical out of said processing bath, thereby performing a first rinsing process using the deionized water; e) supplying a second liquid chemical which is different from said first liquid chemical into said processing bath to force the deionized water out of said processing bath, thereby performing a second liquid chemical process using the second liquid chemical, wherein the second liquid chemical is an SC-1 solution; and f) supplying additional deionized water into said processing bath to force the second liquid chemical out of said processing bath, thereby performing a second rinsing process using the additional deionized water, wherein said step d) includes checking a resistivity of a first processing liquid comprising said deionized water and said first liquid chemical stored in said processing bath after a predetermined time period has elapsed since the start of the first rinsing process for rinsing said first liquid chemical using said deionized water, and said first rinsing process is judged to be completed successfully, when the resistivity of said first processing liquid stored in said processing bath reaches said first resistivity threshold value, and in said step f), the resistivity of a second processing liquid comprising said additional deionized water and said second liquid chemical stored in said processing bath is checked after a given time period has elapsed since the start of the second rinsing process for rinsing said second liquid chemical using said additional deionized water, and said second rinsing process is judged to be completed successfully, when the resistivity of said second processing liquid stored in said processing bath reaches said second resistivity threshold value.