Siloxide Etchant is the preferred etchant for deposited SiO2 films in semiconductor microelectronics. The etchant is formulated as a buffered system containing bifluoride ion. HF activity is regulated by the equilibrium reaction between fluoride, bifluoride and HF buffer compounds. Impurity levels are rigidly controlled to less than 1 ppm concentration of heavy metals to insure quality. There is excellent functional compatibility with both negative and positive photoresists.
PROPERTIES :
| SILOXIDE ETCH
| |
Appearance | Clear liquid |
Specific Gravity | 1.1 |
pH | 5.0 |
Buffer Etch Capacity | 20 mg. SiO2/ml |
Operating Temperature | 25 ¡É |
Storage | Room Temperature |
Compatibel Photoresist | Nega & Posi |
Heavy Metals | < 1 ppm |
Etch Rate @ 25¡É | 40 ¡Ê/second |
APPLICATION :
Siloxide Etchant is used in the photolithographic process for the manufacture of semiconductor devices and integrated circuits. Deposited SiO2 functions in these applications as a passivating dielectric or as an etch mask in conjunction with silicon nitride passivation. Typical SiO2 deposits are on the order of 2000 Å thick.
Conventional buffered HF solutions used to etch thermally grown SiO2 should not be used for deposited SiO2 films. Deposited SiO2 films are produced from the oxidation of silane or by the pyrolytic hydrolysis of ethyl orthosilicate. These deposited silica films etch much faster as compared to thermally grown SiO2. Siloxide Etchant gives the necessary etch control for these deposited SiO2 films.
ETCH CONTROL OF DEPOSITED SiO2 FILM WITH SILOXIDE ETCHANT
ETCH TIME | DEPOSITED SiO2 THICKNESS | REFLECTED COLOR |
Seconds | ¡Ê | --- |
0 | 2150 | YELLOW-ORANGE |
3 | 2100 | YELLOW |
6 | 1900 | GREEN |
9 | 1700 | GREEN-BLUE |
12 | 1500 | BLUE |
15 | 1250 | BLUE-VIOLET |
20 | 1000 | VIOLET |
25 | 900 | VIOLET-BLUE |
30 | 800 | BROWN |
35 | 500 | TAN |
40 | 300 | GRAY |
45 | 100 | GRAY-CLEAR |
50 | 0 | CLEAR |