Classifications

• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W72/00—Interconnections or connectors in packages
  • H10W72/071—Connecting or disconnecting
  • H10W72/075—Connecting or disconnecting of bond wires
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W72/00—Interconnections or connectors in packages
  • H10W72/071—Connecting or disconnecting
  • H10W72/075—Connecting or disconnecting of bond wires
  • H10W72/07531—Techniques

Definitions

• the invention relates to wire bonding operations, and in particular, to techniques for improving wire bonding operations, for example, in terms of time efficiency.
• wire bonding continues to be the primary method of providing electrical interconnection between two locations within a package (e.g., between a die pad of a semiconductor die and a lead of a leadframe). More specifically, using a wire bonder (also known as a wire bonding machine), wire loops are formed between respective locations to be electrically interconnected.
• the primary methods of forming wire loops are ball bonding and wedge bonding.
• bonding energy may be used, including, for example, ultrasonic energy, thermosonic energy, thermocompressive energy, amongst others.
• Wire bonding machines e.g., stud bumping machines are also used to form conductive bumps from portions of wire.
• the process of forming a wire loop includes positioning a wire bonding tool at a height above a workpiece, and then moving the wire bonding tool to contact the workpiece in connection with a wire bonding operation.
• the time that elapses between (i) the height above the workpiece, and (ii) the contact with the workpiece, is critical to the efficiency of the wire bonding operation.
• a method of determining a new search height for a wire bonding process includes: (a) providing a search height; (b) performing a plurality of wire bonding operations using the search height; (c) monitoring wire bonding evaluation criteria during each of the plurality of wire bonding operations of step (b); and (d) determining a new search height using the wire bonding evaluation criteria monitored during step (c).
• a method of determining a new blockout time for a wire bonding process includes: (a) providing a blockout time, the blockout time being a time after a wire bonding tool is at a search height in a wire bonding operation but before the wire bonding tool enters a seek mode; (b) performing a plurality of wire bonding operations using the blockout time; (c) monitoring wire bonding evaluation criteria during each of the plurality of wire bonding operations during step (b); and (d) determining a new blockout time using the wire bonding evaluation criteria monitored during step (c).
• the methods of the present invention may also be embodied as an apparatus (e.g., as part of the intelligence of a wire bonding machine), or as computer program instructions on a computer readable carrier (e.g., a computer readable carrier including a wire bonding program used in connection with a wire bonding machine).
• a computer readable carrier e.g., a computer readable carrier including a wire bonding program used in connection with a wire bonding machine.
• FIG. 1 is a timing diagram illustrating points of interest for performing methods in accordance with various exemplary embodiments of the invention
• FIGS. 2-4 are flow diagrams for performing various methods of determining a new search height for a wire bonding process in accordance with various exemplary embodiments of the invention.
• FIGS. 5-7 are flow diagrams for performing various methods of determining a new blockout time for a wire bonding process in accordance with various exemplary embodiments of the invention.
• Exemplary aspects of the invention relate to monitoring signals on a wire bonding system (e.g., a seek time signal, a seek distance signal, an impact force signal, an impact squash signal, etc.) as feedback to automatically adjust (and to improve, and to potentially optimize) a wire bonding tool height.
• a wire bonding tool height e.g., the search height
• performance and efficiency e.g., UPH, units per hour
• a communication e.g., a warning message
• the wire bonding tool height e.g., the search height
• the monitored seek time (or seek distance) and/or impact force (or impact squash) may be used in connection with a closed loop adjustment of the wire bonding tool height (e.g., the search height).
• a closed loop adjustment may be an automated process (e.g., performed using software on a wire bonding system, without operator intervention).
• a desirable (and perhaps optimal) search height may be achieved when the minimum seek time (or seek distance) meets a threshold. If the seek time (or seek distance) is too long, the UPH of the wire bonding system is negatively impacted. If the seek time (or seek distance) is too short, bonding quality on the wire bonding system may suffer.
• a desirable (and perhaps optimal) impact force may be achieved. If the impact force (or impact squash) is too high, it generally means the search height is too low, potentially resulting in reduced bonding quality.
• the variation of seek time (or seek distance) and impact force (or impact squash) may also be analyzed for wire bonding tool height optimization, to monitor the health of a wire bonding system.
• search height refers to a height of a wire bonding tool above a bonding location at a transition from a high speed to a lower speed.
• An example of search height is a transition point between (i) a high speed descent and (ii) entry into a lower constant velocty (i.e., CV) mode.
• the term “seek time” refers to a time period between (i) an initiation of seeking contact between the wire bonding tool and a bonding location and (ii) a contact being declared between the wire bonding tool and the bonding location.
• the term “seek distance” refers to a distance between (i) an initiation of seeking contact between the wire bonding tool and a bonding location and (ii) a contact being declared between the wire bonding tool and the bonding location.
• seek mode refers to initiation of seeking contact between the wire bonding tool and a bonding location.
• blockout time refers to a time after a wire bonding tool is at a search height in a wire bonding operation but before the wire bonding tool enters a seek mode. In certain applications, the blockout time may be referred to as a "seek delay”.
• FIG. 1 is a timing diagram illustrating points of interest for performing various methods in accordance with the invention (including the embodiments shown in FIGS. 2-7).
• the vertical axis illustrates the z- axis position of a wire bonding tool 100.
• the horizontal axis illustrates time as wire bonding tool 100 descends in connection with a wire bonding operation.
• FIG. 1 illustrates wire bonding tool 100 at an initial position above a workpiece (the workpiece is not illustrated). This initial position refers to some position during a rapid descent of wire bonding tool 100.
• wire bonding tool 100 reaches a search height.
• Wire bonding tool 100 continues to descend between time Tl and time T2.
• the time period between time Tl and time T2 may be referred to as a "blockout time”. This is the time after reaching the search height but before entering a seek mode.
• the seek mode refers to an operational mode during which the system is monitoring for contact between wire bonding tool 100 and a bonding location. Contact between wire bonding tool 100 and the bonding location is declared at time T3. Thus, the time between time T2 (when the seek mode begins) and time T3 (where contact is declared) is referred to as the "seek time” (or if distance is monitored, the "seek distance”).
• FIGS. 2-4 are flow diagrams illustrating exemplary methods of determining a new search height for a wire bonding process in accordance with the invention.
• FIGS. 5-7 are flow diagrams illustrating exemplary methods of determining a new blockout time for a wire bonding process in accordance with the invention. As is understood by those skilled in the art, certain steps included in the flow diagrams may be omitted; certain additional steps may be added; and the order of the steps may be altered from the order illustrated - all within the scope of the invention.
• a method of determining a new search height for a wire bonding process is illustrated.
• a search height is provided (e.g., the search height in FIG. 1).
• a plurality of wire bonding operations are performed using the search height provided from Step 200.
• wire bonding evaluation criteria are monitored during each of the plurality of wire bonding operations of Step 202.
• such wire bonding evaluation criteria may include signals monitored during Step 204 and related to at least one of (i) a seek time of a wire bonding tool, (ii) a seek distance of the wire bonding tool, (iii) an impact force of the wire bonding tool, (iv) an impact squash of the wire bonding tool, (v) a z-axis deformation profile, (vi) a bond force oscillation profile, (vii) an ultrasonic impedance characteristic, and (viii) a servo performance of an xyz motion system of a wire bonding machine.
• a new search height is determined using the wire bonding evaluation criteria monitored during Step 204.
• the criteria monitored during Step 204 may indicate that the seek time (or seek distance) is too long - in which case the new search height may be lower.
• the criteria monitored during Step 204 may indicate that the seek time (or seek distance) is too short - in which case the new search height may be higher.
• different criteria e.g., impact force, impact squash, etc.
• monitored in Step 204 may be used to adjust the search height in Step 206.
• the new search height determined in Step 206 may be the same as the prior search height (e.g., the search height provided at Step 200), or it may be a different search height. According to certain exemplary embodiments of the invention, the new search height may be determined to be low enough to provide a time-efficient wire bonding process while providing an acceptable level of the wire bonding evaluation criteria monitored in Step 204. At optional Step 208, a blockout time is determined for subsequent wire bonding operations using the new search height determined in Step 206. [0027] Referring now to FIG. 3, a method of determining a new search height for a wire bonding process is illustrated. At Step 300, a search height (or a new search height of Step 306) is provided (e.g., the search height in FIG.
• Step 302 a plurality of wire bonding operations are performed using the search height from Step 300 (or a new search height of Step 306).
• Step 304 wire bonding evaluation criteria (see exemplary criteria described above in connection with Step 204) are monitored during each of the plurality of wire bonding operations of Step 302.
• Step 306 a new search height is determined using the wire bonding evaluation criteria monitored during Step 304 (see description above in connection with Step 206).
• Step 308 it is determined if some predetermined criteria is met.
• This predetermined criteria may be any criteria as desired in the specific application.
• the predetermined criteria may be related to criteria monitored in Step 304 (e.g., seek time, seek distance, impact force, impact squash, etc.).
• the predetermined criteria from Step 308 may be different criteria such as a minimum or maximum number of iterations (or a maximum timeout) having been completed. If the answer to the decision block of Step 308 is "no,” Steps 300-306 are repeated with a new search height. If the answer to the decision block of Step 308 is "yes,” at Step 310, a new search height determination is complete.
• a blockout time is determined for subsequent wire bonding operations using the new search height determined in Step 306.
• a method of determining a new search height for a wire bonding process is illustrated.
• a plurality of search heights are to be checked in order to determine a desirable (and perhaps best) search height.
• a plurality of search heights may be known before proceeding with the method, and each of the known plurality of search heights are checked.
• a search height (or another search height of Step 408) is provided (e.g., the search height in FIG. 1).
• a plurality of wire bonding operations are performed using the search height from Step 400 (or another search height of Step 408).
• wire bonding evaluation criteria are monitored during each of the plurality of wire bonding operations of Step 402 (see exemplary criteria described above in connection with Step 204).
• Step 406 a determination is made if another search height is to be checked (i.e., have all of a known plurality of search heights been checked). If the answer to the decision block of Step 406 is "yes," another search height is provided at Step 408 and Steps 400-404 are repeated.
• Step 410 a new search height determination is completed (see description above in connection with Step 206, but also in Step 410 the new search height may be determined using the evaluation criteria monitored for each of the plurality of search heights).
• Step 412 a blockout time for subsequent wire bonding operations is determined using the new search height determined in Step 410.
• a method of determining a new blockout time for a wire bonding process is illustrated.
• a blockout time is provided (e.g., the blockout time in FIG. 1).
• a plurality of wire bonding operations are performed using the blockout time provided from Step 500.
• wire bonding evaluation criteria are monitored during each of the plurality of wire bonding operations of Step 502 (see exemplary criteria described above in connection with Step 204).
• a new blockout time is determined using the wire bonding evaluation criteria monitored during Step 504.
• the new blockout time determined in Step 506 may be the same as the prior blockout time (e.g., the blockout time provided at Step 500), or it may be a different blockout time. According to certain exemplary embodiments of the invention, the new blockout time may be determined to be short enough to provide a time efficient wire bonding process while providing an acceptable level of the wire bonding evaluation criteria monitored in Step 504.
• the search height used for subsequent wire bonding operations is varied based on the new blockout time determined in Step 506. For example, the search height may be increased if the new blockout time is longer (e.g., than a prior blockout time), and decreased if the new blockout time is shorter (e.g., than a prior blockout time).
• Step 600 a blockout time (or a new blockout time of Step 606) is provided (e.g., the blockout time in FIG. 1).
• Step 602 a plurality of wire bonding operations are performed using the blockout time from Step 600 (or a new blockout time of Step 606).
• Step 604 wire bonding evaluation criteria are monitored during each of the plurality of wire bonding operations of Step 602 (see exemplary criteria described above in connection with Step 204).
• Step 606 a new blockout time is determined using the wire bonding evaluation criteria monitored during Step 604. [0035]
• Step 608 it is determined if some predetermined criteria is met.
• This predetermined criteria may be any criteria as desired in the specific application.
• the predetermined criteria may be related to criteria monitored in Step 604 (e.g., seek time, seek distance, impact force, impact squash, etc.).
• the predetermined criteria from Step 608 may be different criteria such as a minimum or maximum number of iterations (or a maximum timeout) having been completed. If the answer to the decision block of Step 608 is "no,” Steps 600-606 are repeated with a new blockout time. If the answer to the decision block of Step 608 is "yes,” at Step 610, a new blockout time determination is complete.
• the search height used for subsequent wire bonding operations is varied based on the new blockout time determined in Step 606 (see description of Step 508 above).
• a method of determining a new blockout time for a wire bonding process is illustrated.
• a plurality of blockout times are to be checked in order to determine a desirable (and perhaps best) blockout time.
• a plurality of blockout times may be known before proceeding with the method, and each of the known plurality of blockout times are checked.
• a blockout time (or another blockout time of Step 708) is provided (e.g., the blockout time in FIG. 1).
• a plurality of wire bonding operations are performed using the blockout time from Step 700 (or another blockout time of Step 708).
• wire bonding evaluation criteria are monitored during each of the plurality of wire bonding operations of Step 702 (see exemplary criteria described above in connection with Step 204).
• Step 706 a determination is made if another blockout time is to be checked (i.e., have all of a known plurality of blockout times been checked). If the answer to the decision block of Step 706 is "yes," another blockout time is provided at Step 708 and Steps 700-704 are repeated.
• Step 710 a new blockout time determination is completed (see description above in connection with Step 506, but also in Step 710 the new blockout time may be determined using the evaluation criteria monitored for each of the plurality of blockout times).
• the search height used for subsequent wire bonding operations is varied based on the new blockout time determined in Step 710 (see description of Step 508 above).

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• 2023
  • 2023-04-25 WO PCT/US2023/019849 patent/WO2023211970A1/en not_active Ceased
  • 2023-04-25 CN CN202380024036.0A patent/CN118872044A/zh active Pending
  • 2023-04-25 JP JP2024551895A patent/JP2025513998A/ja active Pending
  • 2023-04-25 US US18/139,209 patent/US20230352443A1/en active Pending
  • 2023-04-25 KR KR1020247028918A patent/KR20250003487A/ko active Pending
  • 2023-04-26 TW TW112115625A patent/TW202410312A/zh unknown

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