阅读说明：本技术 用于短引线电源装置的冷却和压紧夹具 (Cooling and hold-down fixture for short lead power supply unit ) 是由 戴夫·科菲塔 凯·卢 亚伦·T·瑞多姆斯基 于 2018-09-28 设计创作，主要内容包括：一种夹具被配置为联接到印刷电路板,以冷却和压紧经受反复的电力和热循环的一个或多个电连接部。所述夹具的第一导电柱被配置用以压紧第一电源装置引线和所述印刷电路板的第一印刷电路板迹线之间的第一电连接部,并将热能从所述第一电源装置引线带走。所述第一导电柱从负载散布板延伸。所述负载散布板为将从其延伸的紧固件与所述第一导电柱电隔离的绝缘体。所述紧固件被配置用以与所述电路板配合以将所述夹具连接到所述电路板,使所述负载散布板压紧所述第一导电柱以压紧所述第一电连接部,并将所述夹具接地。(A clamp is configured to be coupled to a printed circuit board to cool and compress one or more electrical connections that are subject to repeated power and thermal cycles. The first conductive post of the clip is configured to compress a first electrical connection between a first power supply device lead and a first printed circuit board trace of the printed circuit board and carry thermal energy away from the first power supply device lead. The first conductive posts extend from the load spreader plate. The load spreader plate is an insulator that electrically isolates fasteners extending therefrom from the first conductive posts. The fastener is configured to mate with the circuit board to connect the clamp to the circuit board, cause the load spreader plate to compress the first conductive post to compress the first electrical connection, and ground the clamp.)

1. A clamp configured to be coupled to a printed circuit board to cool and compress one or more electrical connections subject to repeated power and thermal cycles, the clamp comprising:

a first conductive post configured to compress a first electrical connection between a first power device lead and a first printed circuit board trace of the printed circuit board and to carry thermal energy away from the first power device lead to cool the first power device lead;

a load spreader plate from which the first conductive posts extend; and

a fastener extending from the load spreader plate, the load spreader plate being an insulator that electrically isolates the fastener from the first conductive post, the fastener configured to: cooperating with the circuit board to connect the clip to the circuit board; and causing the load spreader plate to compress the first conductive post to compress the first electrical connection.

2. The clamp of claim 1, further comprising a second conductive post configured to compress a second electrical connection between a second power supply lead and a second printed circuit board trace of the printed circuit board and to carry thermal energy away from the second power supply lead to cool the second power supply lead;

wherein the load spreader plate electrically isolates the second conductive post from both the fastener and the first conductive post; and is

Wherein the fastener is configured to cause the load spreader plate to compress against the second conductive post to compress against the second electrical connection.

3. The clip of claim 2, wherein the first power supply means lead is a first drain lead from a first transistor of a transistor package;

wherein the second power supply means lead is a second drain lead from a second transistor of the transistor package.

4. The fixture of claim 3, wherein the first printed circuit board trace and the second printed circuit board trace energize an RF plasma output network.

5. The clip of claim 2, wherein the first and second conductive posts both comprise a metal.

6. The clamp of claim 5, wherein the metal comprises copper.

7. The clip of claim 2, further comprising a thermal energy dissipation surface on both the first and second conductive posts, the thermal energy dissipation surface configured to release thermal energy conducted from the first and second power supply device leads to the first and second conductive posts.

8. The clip of claim 7, wherein the thermal energy dissipating surface comprises a surface groove.

9. The clamp of claim 1, wherein the load spreader plate comprises fiberglass.

10. The clamp of claim 1, further comprising a compression washer between the head of the fastener and the load spreader plate.

11. The clamp of claim 1, wherein the fastener is a screw.

12. The clamp of claim 2, wherein at least one of the first and second electrical connections is a solder connection.

13. The clamp of claim 2, wherein at least one of the first electrical connection and the second electrical connection is a non-welded connection.

14. The clamp of claim 1, wherein the fastener is further configured to ground the clamp.

15. A clamp configured to be coupled to a printed circuit board to cool and compress one or more electrical connections subject to repeated power and thermal cycles, the clamp comprising:

a conductive post configured to compress an electrical connection between a drain lead of a transistor from a transistor package and a printed circuit board trace that supplies energy to an RF plasma output network, and configured to carry thermal energy away from the first drain lead to cool the first drain lead;

a load spreader plate from which the conductive posts extend; and

a fastener extending from the load spreader plate, the load spreader plate being an insulator that electrically isolates the fastener from the conductive post, the fastener configured to: cooperating with the circuit board to connect the clip to the circuit board; and causing the load spreading plate to press the conductive post to press the electrical connection portion.

16. The clip of claim 15, wherein the transistor package is a dual sub-type package configured in a push-pull configuration for broadband, low distortion operation.

17. The clip of claim 15, further comprising a recessed thermal energy dissipating surface on the conductive post.

18. The clamp of claim 15, wherein the fastener grounds the clamp.

19. A circuit board for an RF plasma generator that provides solid state power for a thin film processing device, the circuit board comprising:

a first transistor mounted to the circuit board with a holding member;

a first drain lead from the first transistor;

a first printed circuit board trace for supplying energy to an RF plasma output network, said first printed circuit board trace connected to said first drain lead to provide a first electrical connection therebetween;

a first conductive post compressing the first electrical connection between the first printed circuit board trace and the first drain lead and configured to carry thermal energy away from the first drain lead to cool the first drain lead;

a load spreader plate from which the first conductive posts extend; and

a fastener extending from the load spreader plate, the load spreader plate being an insulator that electrically isolates the fastener from the first conductive post, the fastener configured to: cooperating with the circuit board to connect the clip to the circuit board; and causing the load spreader plate to compress the first conductive post to compress the first electrical connection.

20. The circuit board of claim 19, further comprising:

a second transistor mounted to the circuit board, the first transistor and the second transistor being included in a transistor package;

a second drain lead from the second transistor;

a second printed circuit board trace for supplying energy to the RF plasma output network, the second printed circuit board trace connected to the second drain lead to provide a second electrical connection therebetween;

a second conductive post pressing against the second electrical connection between a second printed circuit board trace and a second drain lead and configured to carry thermal energy away from the first drain lead to cool the first drain lead;

wherein the load spreader plate electrically isolates the second conductive post from both the fastener and the first conductive post; and is

Wherein the fastener causes the load spreader plate to compress the second conductive posts to compress the second electrical connection.

Technical Field

The present disclosure relates to a cooling and compression clamp for electrical connections that are subject to repeated power and thermal cycles.

Background

This section provides background information related to the present disclosure that is not necessarily prior art.

Soldered electrical connections that undergo repeated thermal expansion and contraction during normal use may experience solder fatigue. Weld fatigue is a common challenge in Radio Frequency (RF) power conversion systems that experience thousands to millions of power cycles over their application life (e.g., RF plasma generators for semiconductor manufacturing). Key parameters that determine the ultimate life of the solder joint include temperature offset (Δ T) and mechanical strain due to the Coefficient of Thermal Expansion (CTE). Repeated power and/or thermal cycling may cause the weld to creep and possibly break, resulting in a high resistance connection and potential connection failure.

While such welded connections are currently suitable for their intended use, they remain to be improved. The present teachings include a cooling and compaction fixture for a short lead power device that advantageously reduces weld fatigue. As described in detail herein and as will be appreciated by those skilled in the art, the present teachings provide a number of additional advantages and unexpected results.

Disclosure of Invention

This section provides a general summary of the disclosure, and is not a complete disclosure of its full scope or all of its features.

The present teachings include a clamp configured to be coupled to a printed circuit board to cool and compress one or more electrical connections that are subject to repeated power and thermal cycles. The first conductive post of the clip is configured to compress a first electrical connection between a first power supply lead and a first printed circuit board trace of the printed circuit board and carry thermal energy away from the first power supply lead. The first conductive posts extend from the load spreader plate. The load spreader plate is an insulator that electrically isolates fasteners extending therefrom from the first conductive posts. The fastener is configured to mate with the circuit board to connect the clamp to the circuit board, cause the load spreader plate to compress the first conductive post to compress the first electrical connection, and ground the clamp.

The present teachings also include a clamp configured to couple to a printed circuit board to cool and compress one or more electrical connections subject to repeated power and thermal cycles. The clamp includes a conductive post configured to compress an electrical connection between a drain lead of a transistor from the transistor package and a printed circuit board trace that supplies energy to the RF plasma output network. The conductive post is also configured to carry thermal energy away from the first drain lead to cool the first drain lead. The conductive posts extend from the load spreader plate. A fastener extends from the load spreader plate, which is an insulator that electrically isolates the fastener from the conductive post. The fastener is configured to: cooperating with the circuit board to connect the clip to the circuit board; and causing the load spreading plate to press the conductive post to press the electrical connection portion.

The present teachings also include a circuit board for an RF plasma generator that provides a solid state power supply (solid state power) for the thin film processing apparatus. The circuit board includes a first transistor mounted to the circuit board with a holding member. A first drain lead extends from the first transistor. The first printed circuit board trace is used to supply power to the RF plasma output network. The first printed circuit board trace is connected to the first drain lead to provide a first electrical connection therebetween. A first conductive post compresses the first electrical connection between the first printed circuit board trace and the first drain lead and is configured to carry thermal energy away from the first drain lead to cool the first drain lead. The first conductive posts extend from the load spreader plate. A fastener extends from the load spreading plate. The load spreader plate is an insulator that electrically isolates the fastener from the first conductive post. The fastener is configured to: cooperating with the circuit board to connect the clip to the circuit board; and causing the load spreader plate to compress the first conductive post to compress the first electrical connection.

Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

Drawings

FIG. 1 illustrates a clamp coupled to a printed circuit board to cool and compress an electrical connection that is subject to repeated power and thermal cycles in accordance with the present teachings; and

FIG. 2 is an isolated perspective view of the clamp of FIG. 1;

corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

Detailed Description

Fig. 1 and 2 illustrate a cooling and compression clamp 10 according to the present teachings. The fixture 10 is configured to be coupled to a printed circuit board 110 to cool and compress one or more electrical connections that are subject to repeated power and thermal cycles. The clamp 10 includes a first post 12A. The first post 12A is made of any suitable conductive material, such as copper. In the illustrated example, the post 12A includes a leg 14A and a foot 16A, which is generally the base of the post 12A. The bottom surface 18A of the foot 16A contacts the electrical connection to compress the electrical connection and conduct thermal energy from the connection, as explained herein. To accommodate the electrical connections, the bottom surface 18A may define a recess 20A.

To facilitate the dissipation of thermal energy from the column 12A and ultimately from the electrical connection, the column 12A may include one or more thermal energy dissipation surfaces. The thermal energy dissipating surface may be located at any suitable location on the post 12A, such as along the leg 14A. The thermal energy dissipating surface may be any suitable surface feature to facilitate the release of heat conducted from the electrical connection to the post 12A. In the illustrated example, the thermal energy dissipating surface is in the form of a first groove 22A.

In the illustrated example, the clamp 10 includes a second post 12B in addition to the first post 12A. The second post 12B is the same as or similar to the first post 12A. Thus, the description of the first column 12A may also describe the second column 12B. Features of the second post 12B that are the same as or similar to features of the first post 12A are designated in the drawings with the same reference numerals but with the suffix "B" instead of "a".

Although the clip 10 is illustrated as including the first post 12A and the second post 12B, the clip 10 may be provided with only one post, or with more than two posts. For example, fig. 1 illustrates a transistor package 130 in the form of a dual sub-package (Gemini package) having two electrical connections associated therewith, as further explained herein. Thus, the exemplary fixture 10 in fig. 1 includes two posts 12A and 12B, one for each electrical connection to be compacted and cooled. The number of posts included in the fixture 10 will generally correspond to the number of electrical connections to be compacted and cooled.

The clamp 10 also includes a load spreader plate 30. The load spreader plate 30 is an insulator and may be made of any suitable insulating material, such as fiberglass. Both the first post 12A and the second post 12B extend from the plate 30. First and second columns 12A and 12B are connected to plate 30 in any suitable manner. For example, the clamp 10 may be preassembled as a separate unit with the first and second columns 12A and 12B attached to the load spreader plate 30 by way of pin staking. The plate 30 defines an aperture 32 that extends through the plate 30. The holes 32 are sized and shaped to receive any suitable fastener 40, the fastener 40 being configured to secure the clip 10 to the circuit board 110. In the illustrated example, the fastener 40 is a screw including a head portion 42 and a shaft portion 44, the shaft portion 44 extending from the head portion 42. Between the fastener 40 (and particularly its head 42) and the plate 30 is a compression member 50. Compression member 50 may be any suitable compression member, such as a washer or spring, that facilitates pressing plate 30 against posts 12A and 12B to press posts 12A and 12B against the electrical connection. If the first and second posts 12A, 12B and the fastener 40 have the same electrical potential, the plate 30 may alternatively be constructed of a conductive material.

At the end of the shaft portion 44 is a thread 46 that mates with an insertion hole of the circuit board 110 to secure the clip 10 to the circuit board 110. The shaft portion 44 is grounded to ground the jig 10. The plate 30 advantageously electrically isolates the fastener 40 from the first and second posts 12A, 12B. The board 30 also isolates RF and DC signals.

As shown in fig. 1, the fixture 10 is positioned such that the first post 12A is located on a first electrical connection formed between a first power device lead 112A and a first printed circuit board trace 114A (or suitable metal surface). The second post 12B is disposed on a second electrical connection between the second power device lead 112B and a second printed circuit board trace 114B (or suitable metal surface). The electrical connection between the first power device lead 112A and the first printed circuit board trace 114A, and the electrical connection between the second power device lead 112B and the second printed circuit board trace 114B, may be any suitable electrical connection, such as any suitable soldered or non-soldered electrical connection.

In the illustrated example, the first power device lead 112A is a first drain (or source) lead from the transistor package 130, in particular, a first drain (or source) lead from its first transistor 132A. The second power device lead 112B is a second drain (or source) lead from a second transistor 132B of the transistor package 130. A first input or gate lead 134A is connected to the first transistor 132A and a second input or gate lead 134B is connected to the second transistor 132B. The transistor package 130 further includes a lid 140 that covers the first transistor 132A and the second transistor 132B. The cover 140 is secured to the circuit board 110 in any suitable manner, such as with a first retaining member 142A and a second retaining member 142B. In the illustrated example, the first printed circuit board trace 114A and the second printed circuit board trace 114B supply power to a plasma chamber 210 for semiconductor manufacturing.

Transistor package 130 is illustrated as a dual sub-type package configured in a push-pull configuration for wideband, low distortion operation. However, any other suitable transistor package may be used. For example, a transistor package including only a single transistor may be used, or a plurality of transistors may be formed on a single chip. The transistor package 130, the first power supply device lead 112A, the second power supply device lead 112B, the first input lead 134A, and the second input lead 134B are included in the RF power supply 150. RF power source 150 may be any power source suitable for providing power to plasma chamber 210 to generate a waveform. The present teachings are applicable for use with any suitable RF plasma generator, such as any suitable VHF generator. The clamp 10 may also be compatible with MKS EDGE^TMThe platform generator is used together.

With the jig 10 arranged as shown in fig. 1, when the fastener 40 is screwed to the circuit board 110, the fastener 40 causes the board 30 to press the first and second posts 12A and 12B, which causes the first post 12A to press the first power supply device lead 112A and causes the second post 12B to press the second power supply device lead 112B. The compression provided by the clamp 10 on the electrical connection is substantially constant. This maintains the electrical connection between the first and second power supply leads 112A and 112B and the first and second printed circuit board traces 114A and 114B, respectively (or any other suitable metal surface), even during large temperature fluctuations at the electrical connection that may cause expansion and contraction of the connection. In addition, the fixture 10 advantageously carries thermal energy away from the first and second power supply device leads 112A, 112B by conduction through the first and second posts 12A, 12B, which reduces the temperature of the first and second power supply device leads 112A, 112B, thereby reducing the likelihood of weld fatigue and extending the life of each electrical connection. The posts 12A and 12B are made of a highly thermally conductive material such as copper, which is a very good material for transferring heat from the leads 112A and 112B to the posts 12A and 12B. The energy accumulated on the copper is then radiated to the surrounding air by means of convection and forced air cooling. The fixture 10 also advantageously minimizes parasitic capacitance from the first and second power supply device leads 112A, 112B to ground, which maintains good RF performance.

To improve heat transfer between the first power device lead 112A and the first post 12A, a thermal interface material 5OA may be disposed therebetween. Similarly, to improve heat transfer between the second power supply device lead 112B and the second column 12B, a thermal interface material 5OB may be disposed therebetween. Thermal interface materials 50A and 50B may be any suitable thermal interface material. For example, thermal interface materials 50A and 50B may each be a sheet (0.25-0.5mm thick) with adhesive on one side, cut to shape, and adhered to bottom surfaces 18A and 18B of posts 12A and 12B, respectively.

The clip 10 is useful in applications where the first and/or second power device leads 112A, 112B are very short (e.g., 3.0 millimeters), which would not use mechanical fasteners, such as screws, to secure the first and/or second power device leads 112A, 112B to their respective traces 114A, 114B. When the first and second power device leads 112A, 112B are very short, they will also be unable to form an omega (Ω) loop as known in the art within the leads 112A, 112B to accommodate expansion and contraction of the first and second power device leads 112A, 112B as their temperatures fluctuate.

The fixture 10 advantageously lowers the temperature of the first and second power device leads 112A and 112B to reduce temperature fluctuations thereof, and holds the fixture 10 against the leads 112A and 112B to reduce mechanical strain caused by repeated thermal expansion and contraction (coefficient of thermal expansion (CTE)). As a result, progressive failure of the weld connection is reduced as estimated by the following formula:

in this equation: f is an engineering coefficient, about 1.2 to 0.7 for fillet joints (filed SJs), and about 1.5 to 1.0 for non-fillet joints (SJs with out files); DNP is the distance from the neutral point/plane; Δ CTE — CTE mismatch; Δ T ═ cyclic temperature shift; h is the weld joint.