JPH03131026A - Cleaning device - Google Patents

Abstract

PURPOSE:To suppress abrasion of a grinding wheel and to prevent wafer from being charged with static electricity without appreciably lowering the resistivity of pure water by cleaning the wafer after cutting with water under high pressure in the ambient atmosphere of ions in the production process for dicing semiconductors formed on the wafer into unit chips and then drying the wafer. CONSTITUTION:Plus electric changes are stored on the surface of a wafer 4 since it is contacted with a jet 6 of pure water under high pressure containing high resistivity CO2. Ions 3 comprising plus and minus ions flow toward the surface of the wafer 4 through a nozzle 2 for blowing the ions from an external ion generator 1. Due to the ions 3, the plus ions stored on the surface of the wafer 4 are neutralized by the minus ions included in the ions 3. Further, the balance of the ions in an ambient atmosphere can be kept by making the generating quantity of the ions 3 greater than the quantity of the charge stored on the surface of the wafer 4. The nozzle 2 for blowing the ions is formed in a ring-like shape within a cover 11 and is provided with a large number of bores on its circumference. A nozzle 8 for jetting N2 is the one by which N2 is blown on the surface of the wafer 4 when drying it, after cleaning by the jet 6 of pure water containing CO2.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a cleaning device using high-pressure water, and can be applied to a cleaning device after cutting a wafer into individual chips. [Prior Art] Conventional cleaning equipment sprays high-pressure water onto the wafer surface through a jet nozzle to clean it, and then sprays nitrogen onto the wafer surface to dry it. [Problems to be Solved by the Invention] Conventional cleaning devices have had the following problems. An oxide film is formed on the wafer surface to protect the devices, making it electrically nonconductive. Furthermore, since pure water is used as the cleaning water, this pure water also has a specific resistance of 15 MΩ·Cm or more. This pure water weighs 50 kg/cm
When pure water is sprayed onto the wafer surface through a jet nozzle at a pressure of "100 kg/cm", static electricity of several kilovolts or more is charged on the wafer surface due to contact between the wafer surface and pure water. This static electricity changes the characteristics of the device, destroys the device due to discharge, and makes the semiconductor defective. Conventionally, as a countermeasure against this problem, carbon dioxide (hereinafter referred to as CO) is bubbled into pure water to make the water weakly acidic with a specific resistance of IMΩ·cm or less. However, this measure cannot completely prevent semiconductor defects because the wafer surface is charged with static electricity of less than lkv, and if the resistivity of pure water is further reduced, cutting using a grindstone to separate the wafer into individual pieces may be necessary. In the process (hereinafter referred to as dicing), the bonding material of the grinding wheel decomposes, causing an adverse effect of increasing the wear of the grinding wheel.The present invention prevents electrostatic charging while lowering the resistivity of pure water too much. To provide a device that does not increase the wear of the [Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention, in the process of separating semiconductors formed on a wafer into individual chips, performs high-pressure water washing and drying in an ion atmosphere to clean the wafer after cutting. This is a cleaning device characterized by:

【Example】

An embodiment of the present invention will be described below with reference to FIG. The wafer 4 after dicing is vacuum suctioned onto a wafer chuck table 9. This wafer chuck table 9 is rotated by a wafer chuck table rotation motor IO. To clean the wafer 4, high-pressure water 7 is introduced from the outside, passes through a jet nozzle 5, becomes a jet stream 6, and hits the surface of the wafer 4, thereby removing foreign substances such as silicon from the surface of the wafer. At this time, the surface of the wafer 4 comes into contact with the jet 6 of COa-containing pure water having high pressure and high specific resistance, so that positive charges are accumulated on the surface. Positive ions and negative ions flow toward the surface of the wafer 4 from an external ion generator 1 through an ion blowing nozzle 2. The positive ions accumulated on the surface of the wafer 4 are neutralized by the negative ions of the ions 3. Note that the ion balance in the atmosphere can be maintained by making the amount of Zeo 230 generated greater than the accumulated charge on the surface of the wafer 4. The ion blowing nozzle 2 is formed in a ring shape within the cover 11, and has numerous holes arranged around its circumference. The N2 injection nozzle 8 is used to spray N2 onto the surface of the wafer 4 when drying the surface of the wafer 4 after cleaning with the CO2-containing pure water jet 6. Ion 3 is CO
□This occurs in all conditions from cleaning by the pure water jet 6 to drying the surface of the wafer 4 by the N2 nozzle 8. The exhaust duct 12 is filled with mist and N during cleaning by the jet stream 6.
This was provided for the purpose of exhausting air in step 2. ion hose 1
3 is a connecting pipe from the ion generator 1 to the ion blowing nozzle 2. The pure water connection pipe 14 is a pipe that guides external high pressure water 7 to the jet nozzle 5. N and 15 are supplied from outside. The N2 connecting pipe 16 is a pipe that leads N215 to the N2 injection nozzle 8. [Effects of the Invention] According to the present invention, static electricity accumulated on the wafer surface in the cleaning process after the guising process can be reduced, and semiconductors no longer become defective due to static electricity. In addition, the specific resistance of pure water can be controlled to about IMΩ·cm, and blade wear can be improved by 20% compared to 0.5 MΩ·cm, and the amount of blade consumption can be reduced.

[Brief explanation of the drawing]

FIG. 1 shows a sectional view of the cleaning device of the present invention.・Ion generator・Ion blast nozzle 3・4・5・6・7・8・9・10・1l・l2・l3・l4・l5・l6・・Ion wafer jet nozzle・Jet flow, high pressure water, N2 injection nozzle, wafer chuck table, wafer chuck table rotation motor, cover, exhaust duct, ion hose, pure water connection pipe, N2, N, connection pipe or higher

Claims (1)

[Claims] A cleaning apparatus characterized in that in a step of separating semiconductors formed on a wafer into individual chips, the wafer is cleaned after cutting by high-pressure water cleaning and drying in an ion atmosphere.