Method and structure for dividing a substrate into individual devices

• US 7,951,688 B2
• Filed: 07/17/2008
• Issued: 05/31/2011
• Est. Priority Date: 10/01/2007
• Status: Active Grant

• Current Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Original Assignee: Fairchild Semiconductor Corporation (ON Semiconductor Corporation)
• Inventors: Reynolds, Matthew, Sim, Gordon, Li, Minhua, Kim, Suku, Murphy, James J., Yilmaz, Hamza, Wang, Qi
• Primary Examiner(s): MANDALA, MICHELLE
• Application Number:
  US12/174,863
• Publication Number:
  US 20090181520A1
• Time in Patent Office: 1,048 Days
• Field of Search: 438/110, 438/118, 438/458, 438/459, 438/462, 438/464, 257/E21.214, 257/E21.237, 257/E21.599
• US Class Current: 438/458
• CPC Class Codes: H01L 21/78 with subsequent division of the substrate into plural individual devices cutting to change the surface-physical characteristics or shape of semiconductor bodies H01L21/304
• CPC Class Codes: H01L 29/7813 with trench gate electrode, e.g. UMOS transistors trench gate electrodes per se H01L29/4236

Abstract

A method for obtaining individual dies from a semiconductor structure is disclosed. The semiconductor structure includes a device layer, and the device layer in turn includes active regions separated by predefined spacings. Thick metal is selectively formed on backside of the device layer such that thick metal is formed on backside of active regions but not on backside of the predefined spacings. The semiconductor structure is then cut along the predefined spacings to separate the active regions with thick metal on their backside into individual dies.

Claims

1. A method for obtaining individual dies from a semiconductor structure that includes a device layer, the device layer in turn including active regions separated by predefined spacings, the method comprising:

selectively forming a metal layer on backside of the device layer such that the metal layer is formed on backside of active regions but not on backside of the predefined spacings; and

cutting the semiconductor structure along the predefined spacings to separate the active regions with the metal layer on their backside into individual dies.

2. The method of claim 1 wherein cutting along the predefined spacings comprises using a die sawing process to cut through the predefined spacings where the metal layer is not formed.

3. The method of claim 2 wherein the predefined spacings comprise scribed line regions.

4. The method of claim 1 wherein the metal layer is formed using selective electroplating.

5. The method of claim 1 further comprising:

prior to forming the metal layer, forming a seed layer over and in contact with the backside of each active region, each seed layer being separated by an adjacent seed layer by a vertically extending structure, the vertically extending structure extending to a height above the seed layer; and

inducing a plating current through each seed layer to thereby induce formation of the metal layer from the corresponding seed layer.

6. The method of claim 5 wherein the seed layer includes a metal layer and a diffusion barrier layer.

7. The method of claim 5 wherein the vertically extending structure is formed using a backside alignment masking process which aligns the vertically extending structure with the scribe line regions.

8. The method of claim 1 wherein the device layer includes a FET structure, the FET structure including:

source regions in an upper portion of the device layer,

a topside metal layer contacting the source regions; and

a drain region extending into a lower portion of the device layer, wherein the metal layer is in direct contact with the drain region along the backside of the device layer, the metal layer being thicker than the topside metal layer.