Automatic semiconductor package inspection method

• US 5,115,475 A
• Filed: 06/04/1990
• Issued: 05/19/1992
• Est. Priority Date: 06/04/1990
• Status: Expired due to Term

• Current Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Lebeau, Christopher J.
• Primary Examiner(s): Boudreau, Leo H.
• Assistant Examiner(s): Johns, Andrew W.
• Application Number:
  US07/532,779
• Time in Patent Office: 715 Days
• Field of Search: 382/8, 382/54, 382/55, 358/106, 358/101, 356/237
• US Class Current: 382/146
• CPC Class Codes: G06T 2207/20036 Morphological image processing
• CPC Class Codes: G06T 2207/30148 Semiconductor; IC; Wafer
• CPC Class Codes: G06T 7/001 using an image reference approach
• CPC Class Codes: H01L 22/20 Sequence of activities consisting of a plurality of measurements, corrections, marking or sorting steps

Abstract

A visual lead-finger inspection method is provided comprising obtaining an image of a semiconductor package and enhancing an image of lead-fingers which are a part of the package. In a first embodiment the image enhancement comprises morphological opening, and in an alternate embodiment comprises direction edge enhancement. A logical AND operation is performed with the enhanced lead-finger image and a frame image which is placed through the lead-finger image, resulting in a data set of only a few hundred bytes which describes position, alignment and lead count of all of the lead-fingers on the package. The data set is compared to a stored data set to determine acceptability of the semiconductor package.

Claims

1. A method of automatically inspecting lead-fingers of a semiconductor package comprising:

providing a sample package;

obtaining an image of lead-fingers of the sample package;

positioning a window around the sample lead-finger image;

building a sample mask image from the sample lead-finger image;

logical ANDing the window with the sample mask image;

obtaining an image of lead-fingers under inspection;

mathematically enhancing the image under inspection;

dilating the enhanced image;

aligning the mask image to the dilated image; and

comparing the mask image to the dilated image to determine acceptability of the lead-fingers.

2. The method of claim 1 wherein the step of building a sample mask image further comprises morphologically opening the image of the lead-fingers.

3. The method of claim 1 wherein the step of building a sample mask image further comprises direction edge enhancement of the lead-finger image.

4. A method of automatically inspecting lead-fingers of a semiconductor leadframe comprising:

obtaining an image of the leadframe, including an image lead-fingers which are a part of the leadframe;

enhancing the image of the lead-fingers;

skeletonizing the enhanced lead-finger image placing a frame image through the enhanced lead-finger image;

performing a logical AND of the enhanced lead-finger image with the frame image to provide a set of data describing the lead-fingers; and

comparing the set of data to a predetermined standard to determine acceptability of the lead-fingers.

5. The method of claim 4 wherein the step of enhancing the image comprises morphological opening of the lead-finger image.

6. The method of claim 4 wherein the step of enhancing the image comprises direction edge enhancement of the lead-finger image.

7. The method of claim 4 wherein the predetermined standard comprises another data set generated from an image of a sample leadframe, wherein the other data set is generated by obtaining an image of the sample leadframe;

enhancing an image of sample lead-fingers which are a part of the sample leadframe image;

placing the frame image through the enhanced sample lead-frame image; and

performing a logical AND operation of the frame image with the enhanced sample lead-finger image.

8. The method of claim 7 further comprising the step of performing morphological dilation of the enhanced image of the sample lead-fingers before the step of performing the logical AND operation of the frame image with the enhanced sample leadfinger image.