Abstract A method of manufacturing rectifying device by cutting a lamination of semiconductor wafers each having a P-N junction formed therein along planes perpendicular to the plane of the wafer and subjecting the resultant divided series diode laminations to an etching treatment with a blend etching liquid composed of hydrogen fluoride, nitric acid and acetic acid. The etching liquid strongly acts upon the N-type region, while it weakly acts upon the P-type region, so that a configuration similar to that which would be obtained through a positive bevel treatment may be obtained. Thus, it is possible to obtain a high breakdown voltage rectifier which is hardly subject to destruction due to a transient reverse voltage.
A METHOD OF MANUFACTURING HIGH BREAKDOWN VOLTGE RECTIFIERS COMPRISING THE STEPS OF CUTTING A SILICON WAFER LAMINATION CONSISTING OF A PLURALITY OF SILICON WAFERS EACH HAVING A P-N JUNCTION FORMED THEREIN ALONG PLANES PERPENDICULAR TO THE PRINCIPAL SURFACE OF THE SILICON WAFERS INTO SLICES OF THE LAMINATED BLOCK, EACH OF SAID SLICES OF THE LAMINATED BLOCK CONSISTING OF A PLURALITY OF DIODES CONNECTED IN SERIES, AND SUBJECTING SAID SLICES OF THE LAMINATED BLOCK TO AN ETCHING TREATMENT WITH A BLEND ETCHING LIQUID COMPOSED OF HYDROFLUORIC ACID WITH A CONCENTRATION OF ABOUT 48 WEIGHT PERCENT, NITRIC ACID WITH A SPECIFIC GRAVITY OF 1.420 AND GLACIAL ACETIC ACID IN A VOLUME RATO OF 2:4:1, THEREBY RENDERING EACH OF SID PLURALITY OF DIODES INTO A BEVEL DIODE.
Claim 2
Independent Claim
124 words
A METHOD OF MANUFACTURING HIGH BREAKDOWN VOLTGE RECTIFIERS COMPRISING THE STEPS OF CUTTING A SILICON WAFER LAMINATION CONSISTING OF A PLURALITY OF SILICON WAFERS EACH HAVING A P-N JUNCTION FORMED THEREIN ALONG PLANES PERPENDICULAR TO THE PRINCIPAL SURFACE OF THE SILICON WAFERS INTO SLICES OF THE LAMINATED BLOCK, EACH OF SAID SLICES OF THE LAMINATED BLOCK CONSISTING OF A PLURALITY OF DIODES CONNECTED IN SERIES, AND SUBJECTING SAID SLICES OF THE LAMINATED BLOCK TO AN ETCHING TREATMENT WITH A BLEND ETCHING LIQUID COMPOSED OF HYDROFLUORIC ACID WITH A CONCENTRATION OF ABOUT 48 WEIGHT PERCENT, NITRIC ACID WITH A SPECIFIC GRAVITY OF 1.420 AND GLACIAL ACETIC ACID IN A VOLUME RATO OF 2:4:1, THEREBY RENDERING EACH OF SID PLURALITY OF DIODES INTO A BEVEL DIODE.
Claim 3
Dependent Claim
16 words
The method according to claim 1, wherein the etching time is within 80 to 120 seconds.