Apparatus and Method for Decapsulating Packaged Integrated Circuits

• US 20130157471A1
• Filed: 12/19/2011
• Published: 06/20/2013
• Est. Priority Date: 12/19/2011
• Status: Active Grant

• Current Assignee: RKD Engineering Corporation Incorporated (RKD Premium Products Incorporated)
• Original Assignee: RKD Engineering Corporation Incorporated (RKD Premium Products Incorporated)
• Inventors: Martin, Kirk Alan
• Granted Patent: US 9,059,184 B2
• Time in Patent Office: Days
• US Class Current: 438/745
• CPC Class Codes: H01L 21/32134 by liquid etching only
• CPC Class Codes: H01L 21/56 Encapsulations, e.g. encapsulation layers, coatings
• CPC Class Codes: H01L 21/67126 Apparatus for sealing, encapsulating, glassing, decapsulating or the like processes H01L23/02, H01L23/28
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A method and system for decapsulating a portion of an encapsulated integrated circuit delivers etchant mixture in variable but precise, high-velocity micro-metered pulses to a single outlet port of a pump from any one of or a combination of separate inlet ports connected to separate etchant source containers holding specific etchant solutions, controls temperature of the etchant mixture by passing the etchant mixture from the outlet port through a serpentine passage in a temperature-controlled metal block, and delivers the etchant mixture from the serpentine passage of the temperature-controlled block via a delivery conduit to an encapsulation surface of the encapsulated integrated circuit.

Claims

1. An acid-etchant decapsulating system for treating an encapsulated integrated circuit, comprising:

an etchant delivery assembly delivering etchant mixture via a delivery conduit to an encapsulation surface of the encapsulated integrated circuit;

a temperature-control system comprising a serpentine passage in a temperature-controlled metal block;

a pump enabled to provide precise, high-velocity micro-metered etchant mixture pulses to a single outlet port from any one of or a combination of separate inlet ports, further enabled to vary the volume and duration of etchant pulses;

two or more etchant source containers holding specific etchant solutions; and

a control station having an operator interface enabling an operator to control variable functions of the system;

wherein the pump is controlled to draw etchant from one or more of the etchant source containers through suitable supply conduits connected to the separate inlet ports, to provide the etchant mixture drawn from the source containers to the singe outlet port in the high-velocity micro-metered pulses, and through a suitable delivery conduit from the single outlet port to the serpentine passage in the temperature-controlled metal block, where the etchant, passing through the serpentine passage, assumes the controlled temperature of the metal block, then to the etchant delivery conduit in the etchant delivery assembly, and thence to the encapsulation surface of the encapsulated integrated circuit, where the etchant attacks the encapsulation material.

2. The decapsulating system of claim 1 wherein the temperature controlled metal block comprises both heating and cooling elements such that delivered etchant mixture may be delivered at a steady temperature above ambient temperature or at a steady temperature below ambient temperature.

3. The decapsulating system of claim 1 further comprising one or more spent-etchant passages proceeding from the encapsulation surface where the etchant mixture is delivered, the spent-etchant passages conducting etchant and products of etching away from the encapsulation surface.

4. The decapsulating system of claim 3 further comprising at least one waste etchant container to which the spent etchant passages deliver spent etchant through a heat exchanger enabled to return the spent etchant to ambient temperature.

5. The decapsulating system of claim 1 further comprising an etch plate having an etch head supporting the encapsulated integrated circuit in a manner to expose the encapsulation surface to the etchant delivered by the delivery conduit, a safety cover sealable to the etch plate forming an etchant chamber, and a vertically-translatable ram enabled when extended downward to hold the encapsulated integrated circuit to the etch head.

6. The decapsulating system of claim 5 wherein the etch head is an insert to the etch plate, such that different specific etch heads may be used to provide for exposure of different areas of encapsulation on different encapsulated integrated circuits.

7. The decapsulating system of claim 5 wherein the vertically-translatable ram is driven by gas pressure provided by electrically operated valves controlled from the control station.

8. The decapsulating system of claim 1 wherein the pump is a diaphragm pump driven by low-pressure gas from a reservoir and controlled from the control station.

9. The decapsulating system of claim 1 comprising a container of nitric acid and a container of sulphuric acid, the encapsulated integrated circuit has copper elements, and the ratio of acids and temperature is controlled to minimize damage to the copper elements of the integrated circuit.

10. A method for decapsulating a portion of an encapsulated integrated circuit, comprising the steps of:

(a) delivering etchant mixture in variable but precise, high-velocity micro-metered pulses to a single outlet port of a pump from any one of or a combination of separate inlet ports connected to separate etchant source containers holding specific etchant solutions;

(b) controlling temperature of the etchant mixture by passing the etchant mixture from the outlet port through a serpentine passage in a temperature-controlled metal block; and

(c) delivering etchant mixture from the serpentine passage of the temperature-controlled block via a delivery conduit to an encapsulation surface of the encapsulated integrated circuit.

11. The method of claim 10 wherein the temperature controlled metal block comprises both heating and cooling elements such that delivered etchant mixture may be delivered at a steady temperature above ambient temperature or at a steady temperature below ambient temperature.

12. The method of claim 10 further comprising a step for removing used etchant mixture via one or more spent-etchant passages proceeding from the encapsulation surface where the etchant mixture is delivered, the spent-etchant passages conducting etchant mixture and products of etching away from the encapsulation surface.

13. The method of claim 12 further comprising a step for delivering the spent etchant to at least one waste etchant container through a heat exchanger enabled to return the spent etchant to ambient temperature.

14. The method of claim 10 further comprising supporting the encapsulated integrated circuit on an etch head in an etch plate in a manner to expose the encapsulation surface to the etchant delivered by the delivery conduit, providing a safety cover sealable to the etch plate forming an etchant chamber, and holding the encapsulated integrated circuit to the etch head by a vertically-translatable ram.

15. The method of claim 14 comprising a step providing the etch head as an insert to the etch plate, such that different specific etch heads may be used to provide for exposure of different areas of encapsulation on different encapsulated integrated circuits.

16. The method of claim 14 providing for driving the vertically-translatable ram by gas pressure provided by electrically operated valves controlled from the control station.

17. The method of claim 10 wherein the pump is a diaphragm pump driven by low-pressure gas from a reservoir and controlled from the control station.

18. The method of claim 10 wherein the integrated circuit has copper elements, and comprising steps for using nitric acid and sulphuric acid in a ratio and at a temperature controlled to minimize damage to the copper elements of the integrated circuit.