Abstract:
The present invention relates to a printed circuit board assembly (10), said printed circuit board assembly comprising: a substrate (100); two or more electronic components which are categorized, wherein each component is secured to the substrate by securing means having a different predetermined thermal-release temperature, depending on which category said component belongs to. The invention furthermore relates to a method of assembling the printed circuit board assembly and a method of disassembling the printed circuit board assembly according to the invention.
Abstract:
A system includes a first module (116) to store times and temperatures for phases in a profile to rework a populated printed circuit board (PCB) (154) for a first integrated circuit (IC) on the PCB and a second module (118) to store suggestions (760) for modifying one or more of the times and the temperatures in the profile to generate a revised profile, the suggestions being associated with pass/fail indications (510) determined from actual temperature (506) information for the profile.
Abstract:
A system includes a first module to store times and temperatures for phases in a profile to rework a populated printed circuit board (PCB) for a first integrated circuit (IC) on the PCB and a second module to store suggestions for modifying one or more of the times and the temperatures in the profile to generate a revised profile, the suggestions being associated with pass/fail indications determined from actual temperature information for the profile.
Abstract:
The invention relates to the device for overvoltage protection containing between the pair of connection points L/N and N/L being connected at least one varistor (V1), which is through the thermal activation disconnectable from the protected electrical circuit, while between the pair of connection points L/N, N/L and the connection point PE of grounding there is connected the aerial discharge (2), and the device further incorporates a basic board (4) created as a printed circuit and containing electrically conductive layer forming at least a part of conductive connections between individual elements of the device. The varistor (V1) is with its one contact (K1) attached to the electric conductive layer of the basic board (4), and in the place of connection of outlet (K1) of varistor (V1) to electric conductive layer of the basic board (4) to the electric conductive layer of the basic board (4) by means of low-fusing joint (5) is attached the electric conductive breaking-off body (6), which is by means of electric conductive heat resistant link (8) connected to one outlet of the aerial discharge (2) and is coupled with the put off means (9).
Abstract:
This invention relates to thermosetting resin compositions useful for mounting onto a circuit board semiconductor devices, such as chip size or chip scale packages ("CSPs"), ball grid arrays ("BGAs"), land grid arrays ("LGAs") and the like, each of which having a semiconductor chip, such as large scale integration ("LSI"), on a carrier substrate. Similarly, the compositions are useful for mouting onto circuit board semiconductor chips themselves. Reaction products of the compositions of this invention are controllably reworkable when subjected to appropriate conditions. And significantly, unlike many commercial rapid curing underfill sealants ("snap cure underfills"), the inventive compositions possess an exotherm under 300 J/g or demonstrate package stability at 55°C for 7 days, and therefore do not require special packaging to be transported by air courier, or special approval from international transportion authorities, such as the U.S. Department of Transportation, to permit such air transport. The inventive compositions possess an exotherm under 300 J/g and/or demonstrate package stability at 55°C for 7 days and therefore do not require special packaging to be transported by air courier, or special approval from intenational transportation authorities, such as the U.S. Department of Transportation, to permit such air transport.
Abstract:
A low heat resistant surface mounting component bonded to a circuit board is removed therefrom without affecting the performance of the circuit board and that the low heat resistant surface mounting component. Solder bumps (3) located on the surface of a low heat resistant surface mounting component (1) in the vicinity (2) of the outer circumference thereof are formed of a low melting point solder as compared with bumps (3) located in the vicinity of the central part. When the low heat resistant surface mounting component (1) on the circuit board is heated locally and removed by fusing the solder bumps, heating temperature in the vicinity of the outer circumference is low as compared with that in the vicinity of the central part. Solder bumps of low melting point solder are thereby employed in the vicinity of the outer circumference so that the solder bumps fuse even at such a low heating temperature. Consequently, the solder bumps on the entire surface of the low heat resistant surface mounting component (1) fuse.
Abstract:
A mounting adapter (50) for a ball grid array package is mounted on a printed board (21), and a ball grid array package (10) on a ball grid array package mounting surface (54) of the adapter (50), this adapter (50) having an aluminum core plate (51), a ball grid array package mounting surface (54) on which a plurality of footprint electrodes (58) are provided, a printed board mounting surface (55) on which a plurality of solder bumps (60) are provided, and stays (51a, 51b) formed of projecting portions of the core plate (51) to which repairing heat is supplied, the solder bumps (60) being formed of high-temperature solder, the repairing heat spreads in the core plate (51), so that the solder bumps of the ball grid array package (10) are heated and melted, whereby the ball grid array package (10) is removed.
Abstract:
The present invention provides a mounting structure for semiconductor devices which enables a semiconductor device (4), such as CSP/BGA, to be securely fixed to a circuit board (5) by short-time heat curing (10), which exhibits good productivity, and excellent heat shock properties (or thermal cycle properties), and which permits the semiconductor device to be easily removed from the circuit board in the event of failure. This invention also provides a mounting process for semiconductor devices.