BLENDED CONTACT FINGERS FOR PREVENTING CRACKS DURING THIN SUBSTRATE HANDLING
A contact for providing a connection to a substrate in a substrate plating system includes a body having an arcuate shape. The arcuate shape of the body is configured to conform to a shape of at least a portion of a substrate arranged on a lip seal and a cup of the substrate plating system. A plurality of first contact fingers extend a first distance from the body. A plurality of second contact fingers extend a second distance from the body. The first distance is greater than the second distance.
This application claims the benefit of U.S. Provisional Application No. 63/018,039, filed on Apr. 30, 2020. The entire disclosure of the application referenced above is incorporated herein by reference.
FIELDThe present disclosure relates to electroplating systems and more particularly to blended contact fingers for electroplating systems.
BACKGROUNDThe background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
In some applications, a substrate such as a semiconductor wafer is thinned using a grinding wheel to a desired thickness prior to downstream processing. The substrate may be too thin to sufficiently support the substrate during grinding, subsequent handling and/or downstream processing. In this situation, the substrate is bonded to a carrier substrate, which acts as a support structure, and later detached from the carrier substrate when processing is complete. Even with the additional support provided by the carrier substrate, the substrate is prone to cracking and chipping during downstream processing.
SUMMARYA contact for providing a connection to a substrate in a substrate plating system includes a body having an arcuate shape. The arcuate shape of the body is configured to conform to a shape of at least a portion of a substrate arranged on a lip seal and a cup of the substrate plating system. A plurality of first contact fingers extend a first distance from the body. A plurality of second contact fingers extend a second distance from the body. The first distance is greater than the second distance.
In other features, the plurality of first contact fingers are configured to contact a seed layer arranged above a substrate bonded to a carrier substrate during plating. The plurality of second contact fingers are configured to contact the carrier substrate at a location outward from a radially outer edge of the substrate during plating. Ones of the plurality of first contact fingers alternate with ones of the plurality of second contact fingers. P of the plurality of first contact fingers are arranged immediate adjacent to one another and Q of the plurality of second contact fingers are arranged immediately adjacent to one another. P and Q are integers greater than or equal to 1. P and Q are equal, greater than one and less than twenty. P is greater than Q. Q is greater than P.
In other features, a plurality of third contact fingers extend a third distance that is different than the first distance and the second distance. A plurality of “U”-shaped cutouts are located between the plurality of first contact fingers and the plurality of second contact fingers. The plurality of first contact fingers are connected together at radially outer ends thereof.
In other features, radially inner ends of at least one of the plurality of first contact fingers has a “V”-shaped profile. The first distance is in a range from 0.6 mm to 4.2 mm and the second distance is in a range from 0.2 mm to 1.0 mm. The first contact fingers have a thickness in a range from 0.001″ to 0.0045″ and the second contact fingers have a thickness in a range from 0.0035″ to 0.007″. The body of the contact is annular.
In other features, the contact includes N ones of the body, each of the N ones spans 360°/N, and the N ones are arranged in a contiguous manner around a periphery of the lip seal. A plating system includes the contact, a cup, and a lip seal arranged on the cup. The contact is arranged between the lip seal and the substrate during plating.
A contact configured to rest on a lip seal of a cup includes a first body having an arcuate shape and including a plurality of first contact fingers extending a first distance from the first body and a plurality of first spaces located between selected ones of the plurality of first contact fingers. A second body has an arcuate shape and includes a plurality of second contact fingers extending a second distance from the second body and a plurality of second spaces located between selected ones of the plurality of first contact fingers. The second distance is greater than the first distance. The first body and the second body are configured to overlap with the plurality of first contact fingers aligned with the plurality of second spaces and with the plurality of second contact fingers aligned with the plurality of first spaces.
In other features, the plurality of second contact fingers are configured to contact a seed layer of a substrate bonded to a carrier substrate. The plurality of first contact fingers are configured to contact the carrier substrate radially outwardly from the substrate. The plurality of first contact fingers are configured to contact a seed layer outwardly from a radially outer edge of the substrate.
A plating system includes the contact, a cup and a lip seal arranged on the cup.
A contact providing an electrical connection to a substrate in a substrate plating system comprises a first body and a second body. The first body has an arcuate shape and includes N first contact fingers extending a first distance from the first body, where N is an integer greater than 1. The second body has an arcuate shape and includes M second contact fingers extending a second distance from the second body, where M is an integer greater than 1, and a ratio of N:M is 1:P, where P is a positive integer. The second distance is greater than the first distance. The N first contact fingers and the M second contact fingers have the same width. The first body and the second body are configured to overlap, with the N first contact fingers aligned with and stacked on top of at least a plurality of the M second contact fingers.
In another feature, P=1, P=2, or P=3.
In another feature, the M second contact fingers are configured to contact a seed layer of a substrate bonded to a carrier substrate.
In another feature, the N first contact fingers are configured to contact the carrier substrate radially outwardly from the substrate.
In another feature, the N first contact fingers are configured to contact a seed layer outwardly from a radially outer edge of the substrate.
Further areas of applicability of the present disclosure will become apparent from the detailed description, the claims and the drawings. The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the disclosure.
The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:
In the drawings, reference numbers may be reused to identify similar and/or identical elements.
DETAILED DESCRIPTIONThe present disclosure relates to contacts used during substrate processing such as plating. The contacts according to the present disclosure include blended contact fingers. A first group of the blended contact fingers is designed to contact a radially outer edge of the substrate bonded to the carrier substrate. The first group of contact fingers provides electrical connections to a seed layer on the substrate during plating. A second group of the blended contact fingers is designed to contact the carrier substrate radially outside of the substrate. The second group of contact fingers help break a seal formed by a lip seal to the substrate.
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The contact fingers serve as an electrical connection from a power supply to the substrate. Some of the contact fingers need to make good electrical contact with the seed layer 214 on the substrate 210. Generally, longer, flatter contact fingers make better electrical contact. Contacts also serve a secondary purpose by providing lift on the substrate after plating to free the substrate from suction against the lip seal 414. Steep angle contacts with more spring force provide better lift, whereas flatter contacts are more prone to sticking to the lip seal 412. Contact fingers (particularly those that provide strong lift) are a key source of wafer cracking/chipping on thin substrates such as active Si wafers.
Systems and methods discussed herein to provide a contact design that makes good electrical contact with the seed layer on the substrate, provides strong lift to prevent wafer sticking to the lip seal after plating, and does not crack or chip the substrate. The present disclosure relates to contacts including blended contact fingers and/or other features addressing the foregoing problems. In some examples, the blended contact fingers include two or more types of contact fingers that are used to contact a single substrate.
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This blended contact finger arrangement has several advantages. The second contact fingers 550 make physical contact with the carrier substrate and typically not with the substrate, which minimizes risk of cracking/chipping. The second contact fingers 550 provide lift to prevent the substrate from sticking to the lip seal.
In some examples, the second contact fingers 550 have a length in a range from 0.2 mm to 1.0 mm (e.g. 0.4 mm). In some examples, the second contact fingers 550 have steeper angle than the first contact fingers 540. In some examples, the angle of a second bend of the second contact fingers 550 closest to the substrate is in a range from 45° to 135° (e.g. 105°).
In some examples, the second contact fingers 550 are stiffer than the first contact fingers 540. For example, the second contact fingers may use a material having a thickness in a range from 0.0035″ to 0.007″ (e.g. 0.004″). In some examples, the second contact fingers 550 can also make electrical contact with the seed layer if the seed layer extends beyond the substrate as shown in
The first contact fingers 540 make electrical contact with the substrate. Characteristics include longer length for good electrical contact. In some examples the length is in a range from 0.6 mm to 4.2 mm (e.g. 1.3 mm). In some examples, the second bends of the first contact fingers 540 have a shallower angle in a range from 45° to 135° (e.g. 115°). In some examples, the first contact fingers 540 are made of a thinner material than the second contact fingers 550. In some examples, the thickness of the first contact fingers 540 is in a range from 0.001″ to 0.0045″ (e.g. 0.002″) to reduce thin wafer cracking and chipping
In some examples, the first contact fingers 540 and the second contact fingers 550 are made of a conductive material. For example, the conductive material may include stainless steel (SS), platinum coated SS, Paliney® 7, beryllium copper, and/or other alloys or metals.
The blended contact fingers described herein enable shallower, gentler electrical contact (using longer length contact fingers) to minimize cracking risk, while reducing sticking risk (using shorter contact fingers) as shown in
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The foregoing description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon a study of the drawings, the specification, and the following claims. It should be understood that one or more steps within a method may be executed in different order (or concurrently) without altering the principles of the present disclosure. Further, although each of the embodiments is described above as having certain features, any one or more of those features described with respect to any embodiment of the disclosure can be implemented in and/or combined with features of any of the other embodiments, even if that combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and permutations of one or more embodiments with one another remain within the scope of this disclosure.
Spatial and functional relationships between elements (for example, between modules, circuit elements, semiconductor layers, etc.) are described using various terms, including “connected,” “engaged,” “coupled,” “adjacent,” “next to,” “on top of,” “above,” “below,” and “disposed.” Unless explicitly described as being “direct,” when a relationship between first and second elements is described in the above disclosure, that relationship can be a direct relationship where no other intervening elements are present between the first and second elements, but can also be an indirect relationship where one or more intervening elements are present (either spatially or functionally) between the first and second elements. As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.”
Claims
1. A contact providing an electrical connection to a substrate in a substrate plating system, comprising:
- a body having an arcuate shape,
- wherein the arcuate shape of the body is configured to conform to a shape of at least a portion of a substrate arranged on a lip seal and a cup of the substrate plating system;
- a plurality of first contact fingers extending a first distance from the body; and
- a plurality of second contact fingers extending a second distance from the body,
- wherein the first distance is greater than the second distance.
2. The contact of claim 1, wherein the plurality of first contact fingers are configured to contact a seed layer arranged above a substrate bonded to a carrier substrate during plating.
3. The contact of claim 2, wherein the plurality of second contact fingers are configured to contact the carrier substrate at a location outward from a radially outer edge of the substrate during plating.
4. The contact of claim 1, wherein ones of the plurality of first contact fingers alternate with ones of the plurality of second contact fingers.
5. The contact of claim 1, wherein P of the plurality of first contact fingers are arranged immediate adjacent to one another and Q of the plurality of second contact fingers are arranged immediately adjacent to one another, where P and Q are integers greater than or equal to 1.
6. The contact of claim 5, wherein P and Q are equal, greater than one and less than twenty.
7. The contact of claim 5, wherein P is greater than Q.
8. The contact of claim 5, wherein Q is greater than P.
9. The contact of claim 1, further comprising a plurality of third contact fingers extending a third distance that is different than the first distance and the second distance.
10. The contact of claim 1, further comprising a plurality of “U”-shaped cutouts located between the plurality of first contact fingers and the plurality of second contact fingers.
11. The contact of claim 10, wherein the plurality of first contact fingers are connected together at radially outer ends thereof.
12. The contact of claim 1, wherein radially inner ends of at least one of the plurality of first contact fingers has a “V”-shaped profile.
13. The contact of claim 1, wherein the first distance is in a range from 0.6 mm to 4.2 mm and the second distance is in a range from 0.2 mm to 1.0 mm.
14. The contact of claim 1, wherein the first contact fingers have a thickness in a range from 0.001″ to 0.0045″ and the second contact fingers have a thickness in a range from 0.0035″ to 0.007″.
15. The contact of claim 1, wherein the body of the contact is annular.
16. The contact of claim 1, wherein:
- the contact includes N ones of the body,
- each of the N ones spans 360°/N, and
- the N ones are arranged in a contiguous manner around a periphery of the lip seal.
17. A contact providing an electrical connection to a substrate in a substrate plating system, comprising:
- a first body having an arcuate shape and including: a plurality of first contact fingers extending a first distance from the first body; and a plurality of first spaces located between selected ones of the plurality of first contact fingers; and
- a second body having an arcuate shape and including: a plurality of second contact fingers extending a second distance from the second body; and a plurality of second spaces located between selected ones of the plurality of first contact fingers,
- wherein the second distance is greater than the first distance, and
- wherein the first body and the second body are configured to overlap with the plurality of first contact fingers aligned with the plurality of second spaces and with the plurality of second contact fingers aligned with the plurality of first spaces.
18. The contact of claim 17, wherein the plurality of second contact fingers are configured to contact a seed layer of a substrate bonded to a carrier substrate.
19. The contact of claim 18, wherein the plurality of first contact fingers are configured to contact the carrier substrate radially outwardly from the substrate.
20. The contact of claim 17, wherein the plurality of first contact fingers are configured to contact a seed layer outwardly from a radially outer edge of the substrate.
Type: Application
Filed: Apr 12, 2021
Publication Date: Jun 8, 2023
Inventors: Stephen J. BANIK (Philadelphia, PA), John Floyd OSTROWSKI (Lake Oswego, OR), Bryan BUCKALEW (Tualatin, OR), Robert RASH (West Linn, OR), Meng Wee Edwin GOH (Wilsonville, OR), Santosh KUMAR (Beaverton, OR), Frederick Dean WILMOT (Gladstone, OR)
Application Number: 17/921,930