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Numéro de publicationUS3632462 A
Type de publicationOctroi
Date de publication4 janv. 1972
Date de dépôt7 févr. 1969
Date de priorité9 févr. 1968
Autre référence de publicationDE1905732A1
Numéro de publicationUS 3632462 A, US 3632462A, US-A-3632462, US3632462 A, US3632462A
InventeursColin Arthur Barrington
Cessionnaire d'origineLucas Industries Ltd
Exporter la citationBiBTeX, EndNote, RefMan
Liens externes: USPTO, Cession USPTO, Espacenet
Dicing of semiconductors
US 3632462 A
Résumé
In the manufacture of semiconductors by forming a large number of devices on one wafer, protecting the individual devices by wax masks and then subjecting the wafer to an etching acid to separate the devices, apparatus is used for separating the wafers comprising a tray on which the wafer is placed. Means is provided for circulating an etching acid in a path including the tray, and in this path there is means for controlling the temperature of the acid.
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Description  (Le texte OCR peut contenir des erreurs.)

United States Patent m1 3,632,462

[72] Inventor Colin Arthur Harrington [50] Field of Search 156/345, 17

Sutton Coldfield, England [21] Appl. No. 797,610 Relerences Cited [22] Filed Feb. 7, 1969 UNITED STATES PATENTS Patented Jan. 4, 1972 std Limited 3,095,463 6/ 1963 Chang et al [56/345 UX [73] Amgnee g es) Primary Examiner-Jacob H. Steinberg 32 Priority Feb. 9, 1968 5mm [3 3] Great Britain ABSTRACT: In the manufacture of semiconductors by forming a large number of devices on one wafer, protecting the in- [54] meme 0F SEMCONDUCTORS dividual devices by wax masks and then subjecting the wafe;

4 Claims 1 Dnwing a. to an etchrng acid to separate the devices, apparatus IS use for separating the wafers compnsmg a tray on which the wafer [52] US. Cl. 156/345, is placed, Means is provided for circulating an etching acid in 156/17 a path including the tray, and in this path there is means for [5] 1 Int. Cl. controlling the temperature of the acid HE T /4 PUMP EXCHANGE? rmmeum 41972 31632462 L? 15 i5? EXCHANGEE I/ H i 15 PUMP /7 {9 INVE TO? I xi" AWO ENEYS meme F SEMICONDUCTORS In the manufacture of semiconductors it is common to form a large number of devices on one wafer, then to protect the individual devices by wax masks and to subject the wafer to an etching acid to separate and dice the devices. This invention relates to apparatus for performing the etching operation.

Apparatus according to the invention comprises a tray on which the wafer is placed, means for circulating an etching acid in a path including said tray, and means in said path for controlling the temperature of the acid.

The usual arrangement is merely to pour acid into the tray without any circulation or temperature control. For this reason the life of a given batch of acid is limited, because if the acid temperature is too low the etching time is increased, but if the acid temperature becomes too high, the wax masks tend to become lifted from the wafer. Using the conventional technique, a typical arrangement using three liters of acid will etch 20 wafers. An arrangement in accordance with one example of the invention using 12 liters of acid which was circulated was found to etch successfully 160 wafers of the same size, an overall improvement of 100 percent.

An example of the invention is illustrated diagrammatically in the accompanying drawing.

Referring to the drawing, there is provided a tray 11 in which wafers to be etched are placed, the tray having an inlet for a suitable etching acid, and an outlet, so that acid flows through the tray continuously. A suitable acid is of known fon'n including nitric acid, hydrofluoric acid and acetic acid. From the outlet, acid flows to a reservoir 12, from which a pump 13 supplies the acid to a water-cooled heat exchanger 14, which in turn supplies the acid to the inlet of the tray. The outlet of the pump may be connected to the tray through some form of valve 15 to control the amount of acid supplied to the tray.

Between the outlet of the tray and the reservoir 12 is a temperature probe 16 for sensing the temperature of the acid leaving the tray, the probe being connected to a solenoid which operates a valve controlling the amount of water flowing to the heat exchanger. Water is circulated from a reservoir 17 to the heat exchanger 14 by a pump 18 at a rate determined by a valve 19 which in turn is controlled by a solenoid 21 connected to an controlled by the probe 16. The arrangement is such that the acid is kept at a constant temperature which is chosen to be sufficiently low to avoid removal of the wax masks on the wafer, but sufficiently high to ensure that etching takes place at an acceptable rate. A suitable temperature using a typical wax having a melting point of C. is in the range 10 to 14 C., preferably.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. ln an apparatus for performing a separation etching operation on a wax-masked semiconductor wafer, to dice said wafer comprising a tray on which the wafer is placed and means for circulating an etching acid in a path including said tray, the improvement comprising cooling means in said path for controlling the temperature of the acid.

2. Apparatus as claimed in claim 1 in which a pump supplies acid to the tray through a heat exchanger, the temperature of the etching acid being sensed by a temperature probe which controls the rate of supply of coolant to the heat exchanger.

3. Apparatus as claimed in claim 2 including a valve for controlling the rate of flow of the etching acid.

4. In a method of dicing semiconductors, said method comprising the steps of forming a number of devices on one wafer; applying wax masks to the individual devices to protect the individual devices; placing the devices on a tray and circulating etching acid therethrough; the improvement comprising cooling the circulating etching acid.

Citations de brevets
Brevet cité Date de dépôt Date de publication Déposant Titre
US3095463 *12 mars 195825 juin 1963Crucible Steel Co AmericaTemperature control apparatus
Référencé par
Brevet citant Date de dépôt Date de publication Déposant Titre
US3964957 *30 sept. 197422 juin 1976Monsanto CompanyApparatus for processing semiconductor wafers
US4142893 *14 sept. 19776 mars 1979Raytheon CompanySpray etch dicing method
US4633893 *24 juin 19856 janv. 1987Cfm Technologies Limited PartnershipApparatus for treating semiconductor wafers
US4738272 *24 juin 198519 avr. 1988Mcconnell Christopher FVessel and system for treating wafers with fluids
US4740249 *24 oct. 198626 avr. 1988Christopher F. McConnellMethod of treating wafers with fluid
US4778532 *13 août 198518 oct. 1988Cfm Technologies Limited PartnershipProcess and apparatus for treating wafers with process fluids
US4856544 *25 nov. 198715 août 1989Cfm Technologies, Inc.Vessel and system for treating wafers with fluids
US4911761 *20 avr. 198827 mars 1990Cfm Technologies Research AssociatesProcess and apparatus for drying surfaces
US4917123 *3 oct. 198817 avr. 1990Cfm Technologies Limited PartnershipApparatus for treating wafers with process fluids
US4984597 *3 nov. 198915 janv. 1991Cfm Technologies Research AssociatesApparatus for rinsing and drying surfaces
US5286657 *18 déc. 199115 févr. 1994Verteq, Inc.Single wafer megasonic semiconductor wafer processing system
US6143087 *19 févr. 19997 nov. 2000Cfmt, Inc.Methods for treating objects
US63288098 janv. 199911 déc. 2001Scp Global Technologies, Inc.Vapor drying system and method
US634810126 sept. 200019 févr. 2002Cfmt, Inc.Methods for treating objects
US751828816 août 200714 avr. 2009Akrion Technologies, Inc.System for megasonic processing of an article
US825750511 oct. 20114 sept. 2012Akrion Systems, LlcMethod for megasonic processing of an article
Classifications
Classification aux États-Unis438/465, 156/345.18
Classification internationaleG05D23/19, C23F1/08, H01L21/00
Classification coopérativeC23F1/08, G05D23/1919, H01L21/00
Classification européenneH01L21/00, G05D23/19E, C23F1/08