Apparatus and method for mounting or wiring semiconductor chips

• US 7,193,727 B2
• Filed: 09/10/2004
• Issued: 03/20/2007
• Est. Priority Date: 09/12/2003
• Status: Expired due to Fees

• Current Assignee: Unaxis International Trading Ltd.
• Original Assignee: Unaxis International Trading Ltd.
• Inventors: Blessing, Patrick
• Primary Examiner(s): Pham; Hoa Q.
• Application Number:
  US10/938,430
• Publication Number:
  US 20050056947A1
• Time in Patent Office: 921 Days
• Field of Search: 3562371-2375, 356601-623, 356630-632, 156/358, 156/352, 156/378
• US Class Current: 356/604
• CPC Class Codes: H01L 2224/32145 the bodies being stacked
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/83121 Active alignment, i.e. by apparatus steering, e.g. optical alignment using marks or sensors
• CPC Class Codes: H01L 2224/83192 wherein the layer connectors are disposed only on another item or body to be connected to the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/8385 using a polymer adhesive, e.g. an adhesive based on silicone, epoxy, polyimide, polyester
• CPC Class Codes: H01L 24/29 of an individual layer connector
• CPC Class Codes: H01L 24/32 of an individual layer connector
• CPC Class Codes: H01L 24/75 Apparatus for connecting with bump connectors or layer connectors
• CPC Class Codes: H01L 24/83 using a layer connector
• 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 2924/01005 Boron [B]
• CPC Class Codes: H01L 2924/01006 Carbon [C]
• CPC Class Codes: H01L 2924/01015 Phosphorus [P]
• CPC Class Codes: H01L 2924/01027 Cobalt [Co]
• CPC Class Codes: H01L 2924/01033 Arsenic [As]
• CPC Class Codes: H01L 2924/01066 Dysprosium [Dy]
• CPC Class Codes: H01L 2924/01082 Lead [Pb]
• CPC Class Codes: H01L 2924/04953 TaN
• CPC Class Codes: H01L 2924/07802 not being an ohmic electrical conductor
• CPC Class Codes: H01L 2924/12042 LASER

Abstract

An apparatus for mounting semiconductor chips onto a substrate contains a measuring station for the contactless measurement of the height of the surface of the mounted semiconductor chip facing away from the substrate at a minimum of three locations. From this, at least one parameter is calculated that characterises the adhesive layer formed between the semiconductor chip and the substrate. A difference of the measured value to a set value is used to adjust the mounting process. An apparatus for wiring semiconductor chips also contains such a measuring station in order to determine the individual height of each connection point on the semiconductor chip. This information is used in order to lower the capillary to the respective connection point on the semiconductor chip in the shortest possible time.

Claims

1. An apparatus for mounting semiconductor chips onto a substrate, whereby an adhesive layer is formed between the substrate and the semiconductor chip, comprising

a camera, in an image of which the semiconductor chip and parts of the substrate surrounding the semiconductor chip are visible,

a light source for producing and projecting a light grid consisting of at least two lines onto the substrate, whereby the lines of the light grid impinge obliquely on the substrate at a predetermined projection angle so that each of the lines of the light grid impinging on the semiconductor chip is offset on at least two edges of the semiconductor chip, and

an image processing unit for calculating at least one parameter characterising the adhesive layer from the image delivered by the camera based on at least three offsets.

2. The apparatus according to claim 1, wherein the at least one parameter characterising the adhesive layer is an average thickness of the adhesive layer.

3. A method for mounting semiconductor chips onto a substrate, the method comprising the steps:

lowering a bondhead carrying a semiconductor chip to a height H above a substrate for mounting the semiconductor chip onto the substrate,

determining at least one parameter characterizing an adhesive layer that is formed between the substrate and the semiconductor chip,

from a possible deviation of the at least one parameter from a set value calculating a correction value Δ

H, and

lowering the bondhead to a height H+Δ

H for mounting a subsequent semiconductor chip, wherein the determination of the at least one parameter comprises the following steps;

projecting a light grid comprising at least two lines onto the substrate with the semiconductor chip, whereby the lines of the light grid impinge obliquely on the substrate so that each of the lines of the light grid impinging on the semiconductor chip is offset on at least two edges of the semiconductor chip,

recording an image of the semiconductor chip and parts of the substrate surrounding the semiconductor chip, and

calculating the at least one parameter based on at least three offsets of the lines of the light grid on the at least two edges of the semiconductor chip.

4. The apparatus according to claim 3, wherein the at least one parameter characterising the adhesive layer is an average thickness of the adhesive layer.

5. A method for mounting semiconductor chips onto a substrate, the method comprising the following steps:

placing a semiconductor chip on a substrate and pressing the semiconductor chip against the substrate for a time τ and

with a force F,

determining at least one parameter characterizing an adhesive layer that is formed between the substrate and the semiconductor chip,

from a possible deviation of the at least one parameter from a set value calculating a correction value Δ

τ and

/or a correction value Δ

F,

and placing a subsequent semiconductor chip on the substrate and pressing the subsequent semiconductor chip against the substrate for a modified time τ

+Δ

τ and

/or with a modified force F+Δ

F,

wherein the determination of the at least one parameter comprises the following steps;

projecting a light grid comprising at least two lines onto the substrate with the semiconductor chip, whereby the lines of the light grid impinge obliquely on the substrate so that each of the lines of the light grid impinging on the semiconductor chip is offset on at least two edges of the semiconductor chip,

recording an image of the semiconductor chip and parts of the substrate surrounding the semiconductor chip, and

calculating the at least one parameter based on at least three offsets of the lines of the light grid on the at least two edges of the semiconductor chip.

6. The method according to claim 5, wherein the at least one parameter characterising the adhesive layer is an average thickness of the adhesive layer.