Method of fabricating an array of semiconductor devices

• US 4,040,169 A
• Filed: 12/29/1975
• Issued: 08/09/1977
• Est. Priority Date: 03/04/1974
• Status: Expired due to Term

• Current Assignee: Stellex Microwave Systems, Inc. (Johnson Controls International plc)
• Original Assignee: Watkins Johnson Co. (Qorvo, Inc.), Signetics Corporation
• Inventors: Rose, Ralph E.
• Primary Examiner(s): Tupman, W.
• Application Number:
  US05/644,515
• Time in Patent Office: 589 Days
• Field of Search: 29/577, 29/576 S, 29/589, 29/203 P, 29/203 J, 29/203 V, 228/180 A, 228/6
• US Class Current: 438/67
• CPC Class Codes: H05K 13/046 Surface mounting surface mounted components H05K3/341
• CPC Class Codes: Y10T 29/49133 with component orienting
• CPC Class Codes: Y10T 29/53191 Means to apply vacuum directly to position or hold work part
• CPC Class Codes: Y10T 29/53261 Means to align and advance work part

Abstract

A method for fabricating a semiconductor diode array, utilizing an alignment tool to precisely position a plurality of diodes so that they can be bonded into a precision array. The alignment tool and a method for fabricating the tool are also disclosed.

Claims

1. In a method of fabricating an array of semiconductor devices on a substrate utilizing an alignment tool having a body with a plurality of spaced apart recesses with outwardly diverging side walls extending to one surface thereof, the steps of:

forming a plurality of individual semiconductor devices having bonding pads on one side thereof and inclined side walls diverging toward the bonding pads, placing the individual semiconductor devices in the recesses in the alignment tool with the inclined walls of the semiconductor devices engaging the outwardly diverging walls of the recesses and the bonding pads protruding beyond the surface of the tool, forming a metallized layer on one surface of the substrate, positioning the surfaces of the alignment tool and the substrate in confronting relationship with the bonding pads aligned with predetermined portions of the metallized layer, heating the metallized layer to a predetermined temperature, and pressing the alignment tool and substrate together to bring the bonding pads into contact with the metallized layer and thereby effect bonding of the semiconductor devices to the substrate.

2. The method of claim 1 wherein the semiconductor devices are held in the tool by applying a vacuum to the recesses.

3. The method of claim 1 wherein the alignment tool is removed when the substrate has cooled to a predetermined temperature.

4. In a method for fabricating a diode array on a substrate using an alignment tool of the type having spaced recesses formed in a body adapted to receive discrete diodes of the type having diode bonding pads with the diode bond pads protruding above the surface of the body, the steps of:

forming a metal layer containing gold on the surface of the substrate patterned to correspond with the diode bond pads of the spaced diodes, heating the substrate to a temperature on the order of 450°

C., aligning the diode bond pads to confront the corresponding substrate pattern, bringing the confronting bond pads and the substrate pattern into contact, pressing the pads and pattern together with a pressure on the order of 5 pounds or less for a period on the order of 5 to 10 seconds, allowing said substrate to cool to a temperature on the order of 250°

C., and removing said tool from the diode array at said temperature.

5. A method as in claim 4 wherein the metal layer comprises a gold and silicon eutectic and the diode bond pads are formed by forming a 100 to 300 Angstrom nickel layer on an exposed silicon surface of each diode, and forming a gold layer having a thickness on the order of 1,000 Angstroms on the nickel layer.

6. A method as in claim 4, wherein the metal layer comprises a gold and tin eutectic and the diode bond pads are formed by forming a titanium layer on the order of 100 to 300 Angstroms in thickness on an exposed silicon surface of each diode, forming a second layer having a thickness on the order of 1,000 to 1,500 Angstroms from a metal selected from the group consisting of platinum or molybdenum on the titanium layer, and forming a gold layer on the order of 1,000 Angstroms in thickness on the second layer.