|Publication number||US20050013106 A1|
|Application number||US 10/621,882|
|Publication date||Jan 20, 2005|
|Filing date||Jul 17, 2003|
|Priority date||Jul 17, 2003|
|Also published as||CN1823339A, CN1823341A, CN100589121C, EP1649413A1, US7307848, US20050014298, WO2005010812A1|
|Publication number||10621882, 621882, US 2005/0013106 A1, US 2005/013106 A1, US 20050013106 A1, US 20050013106A1, US 2005013106 A1, US 2005013106A1, US-A1-20050013106, US-A1-2005013106, US2005/0013106A1, US2005/013106A1, US20050013106 A1, US20050013106A1, US2005013106 A1, US2005013106A1|
|Original Assignee||Takiar Hem P.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (25), Referenced by (25), Classifications (30), Legal Events (1)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This Application is related to U.S. patent application Ser. No. ______, “Method For Efficiently Producing Removable Peripheral Cards,” filed Jun. 23, 2003, Hem P. Takiar, Atty. Docket SDK1P014/370, which is incorporated herein by reference in its entirety.
1. Field of the Invention
The present invention is directed to technology for peripheral cards.
2. Description of the Related Art
Memory cards are relatively small removable cards that provide data storage. In most cases, but not required in all cases, the memory card is integrated circuit based. These memory cards plug into or are received by ports or connectors on electronic devices, including computing devices, cameras, mobile telephones, PDAs and other devices. One example of a memory card uses non-volatile memory. Electrical Erasable Programmable Read Only Memory (EEPROM) and flash memory are among the most popular non-volatile semiconductor memories. Some examples of memory cards includes CompactFlash™, MMC™, Smart Media, Secure Digital™, and the Memory Stick.
A flash memory card is a memory card that has one or more arrays of flash memory cells. Some flash memory cards also include bit line decoders, word line decoders, a state machine, a controller and other circuitry. In many cases the controller will be implemented in a first semiconductor die, while the array of flash memory cells, bit line decoders, word line decoders, and state machine are implemented in a second semiconductor die. Over time, flash memory arrays have increased density by shrinking the size of an individual memory cell and by implementing greater numbers of memory cells in the array.
To maintain product reliability and customer satisfaction, manufacturers of memory cards will test the memory cards during the manufacturing process in order to determine if there are any manufacturing defects. In many cases, the user I/O pins on the memory card connect to the controller. However, a test performed during manufacturing typically seeks to directly access the memory array (bypassing the controller) in order to test each cell in the memory array. Additionally, more pins will allow for more efficient and complete testing of the relevant components of the memory card. Thus, many memory cards will include test pins, in addition to the user I/O pins. To protect the memory card from electrostatic discharge relative to the test pins and to protect the data on the card from being wrongfully accessed via the test pins, the test pins should not be exposed to the user of the memory card after the manufacturing process.
One example of a memory card is described in U.S. Pat. No. 6,410,355 (the '355 patent”), incorporated herein by reference in its entirety. In the '355 patent, a memory card using flash memory is manufactured with a set of test pins at one edge of the memory card. After the memory card is tested, the test pins are cut off of the memory card and the memory card is then packaged. While the device of the '355 patent has worked well, there is a need for an improvement. First, the test pins that are cut off use real estate on the circuit board. There is a trend to increase density on circuit boards; therefore, it would be advantageous to not use a portion of the circuit board for components that will not ship to customers. Second, if the memory card fails in the field, there are no test pins to test the device in order to determine why the memory card failed. Such tests following device failure allow a manufacturer of memory cards to improve device reliability and the manufacturing process.
Another example of a memory card using flash memory is the recently released Mini-SD Card. In one commercial version of the Mini-SD Card, the memory array is mounted on the top of the circuit board and the controller is mounted on the memory array. User I/O pins and test pins are formed on the bottom of the circuit board. After the memory card is tested, the circuit board (with the controller, memory array and other components) are enclosed by attaching a top lid to a bottom lid. Both the bottom lid and the top lid are made of a hard plastic, and are manufactured from a mold prior to enclosing the circuit board. After the top and bottom lids are made, the top lid is ultra- sonically welded to the bottom lid to enclose the circuit board (with the controller, memory array and other components). The bottom lid has an opening for the user I/O pins. The bottom lid does not have an opening for the test pins; therefore, the test pins are not exposed to users. There will be a small air gap between the bottom lid and the bottom of the circuit board While this design works well, the top and bottom lids are relatively expensive to manufacture. Additionally, the lids are relatively bulky which limits how small the memory cards can be manufactured. The trend in the industry to further decrease the size of memory cards.
Thus, there is a need to provide for test pins for a memory card without the limitations described above. Similar issues exist with other types of peripheral cards, such as peripheral cards that implement wireless communication devices, GPS devices, cellular devices, network interfaces, modems, disk storage systems, and other devices.
The present invention, roughly described, pertains to technology for a peripheral card with hidden test pins. One embodiment of the present invention includes a circuit board, circuit elements on said circuit board, a set of user terminals on the circuit board that are in communication with at least a subset of the circuit elements, a set of test terminals on said circuit board that are in communication with one or more of the circuit elements, an enclosure that covers a portion of the circuit board without covering the set of user terminals and the set of test terminals, and a conformal contact coating on a first surface of the circuit board covering the test terminals and preventing access to the test terminals.
One embodiment of manufacturing such a peripheral card includes adding circuit elements to a circuit board, where the circuit board (at some point in time) includes a set of test terminals. One or more of the circuit elements are tested using the test terminals. The test terminals are subsequently covered with a conformal contact coating in order to prevent access to the test terminals. In one implementation, the test terminals are covered with a conformal contact coating by applying a liquid directly to a first surface of the circuit board. In another implementation, the test terminals are covered with a conformal contact coating by applying a film directly to a first surface of said circuit board.
Some embodiments of the present invention will include manufacturing the peripheral cards a batch at a time, followed by singulation of the batch into individualized memory cards. The present invention allows for the covering of the test pins before or after singulation. For example, one implementation includes the steps of adding circuit elements to a plurality of circuit boards of a strip (each of the plurality of circuit boards includes a set of test terminals), separating the connected circuit boards, testing the circuit elements of the circuit boards using the test terminals, and applying a conformal contact coating on a first surface of each of the circuit boards. The conformal contact coating covers the test terminals and prevents access to the test terminals such that a particular circuit board has its test terminals covered after that particular circuit board has been tested.
The present invention can be applied to the manufacture of memory cards, including flash memory cards. The technology disclosed herein can also be applied to other peripheral cards. For example, the present invention can be used with removable peripheral cards that include wireless communication devices, GPS devices, cellular devices, network interfaces, modems, disk storage systems, and other devices. The present invention is not limited to any one type of peripheral card and is meant to be used with many different types of peripheral cards.
These and other objects and advantages of the present invention will appear more clearly from the following description in which the preferred embodiment of the invention has been set forth in conjunction with the drawings.
In one implementation, the memory card is 12 mm wide and 15 mm long. The angled portion is at a forty five degree angle. The thickness of the memory card is 0.9 mm at second portion 24, 1.0 mm at raised portion 18 and 0.8 mm at first portion 22. In another embodiment, the thickness of the memory card is 0.8 mm at second portion 24, 1.0 mm at raised portion 18 and 0.7 mm at first portion 22. In other embodiments, other dimensions can also be used.
In one embodiment, a label will be placed on the top surface. This label can be a sticker or can be ink which is pad printed.
Subsequent to encapsulation, a conformal contact coating 290 is applied to a portion of the bottom surface of circuit board 200 in order to cover test pins 232. The conformal contact coating does not cover user I/O pins 230.
In one embodiment, the application of the conformal contact coating includes applying a liquid directly to the bottom surface of the circuit board. The coating then dries to a solid. In another embodiment, the coating is applied as a film directly to the bottom surface of the circuit board. Examples of coatings include photoresist, solder mask, epoxy, thermoplastic, and polyimide. One specific example of a suitable coating is the PSR-400 Solder Mask from Taiyo America, Inc., www.taivo-america.com. Examples of a film include mylar with an adhesive or polyimide with an adhesive. An example of a suitable polyimide is Kapton, by DuPont. One example of how to apply a liquid coating is to use a screen printing process.
In one embodiment, a memory card is manufactured as a unitary structure. In that case, step 420 is skipped and the process of
In step 422, the memory cards are tested. In step 424, the test pins are covered, as described above, by applying the conformal contact coating to a portion of the bottom surface of the circuit board 200 (e.g. bottom portion 24 of
Step 422 includes testing the memory cards. During the manufacturing process, the manufacturer may perform a bum-in test of the memory card to verify that each of the memory cells in the memory array are functional. The manufacturer may then program the memory card to avoid bad memory cells. For example, the memory array may include a portion of memory that stores addresses for bad memory cells and pointers to replacement memory cells. In some embodiments, the other components of the memory card may also be tested. Note that
If the memory card fails after it is in use, then the failed memory card can be debugged by removing the conformal contact coating and using the test pins to test the memory card.
The description above specifically discusses memory cards. One set of embodiments of the present invention specifically pertain to flash memory cards, which include one or more memory arrays that utilize flash memory technology. The embodiments explained above pertaining to memory cards are for example purposes and are not mean to limit the invention. The technology disclosed herein can also be applied to other peripheral cards that connect to a computing device and are controlled or operated with the computing device. One example of a removable peripheral card is a PCMCIA card. Examples of applications, in addition to memory systems, that can be implemented on peripheral cards include wireless communication devices, GPS devices, cellular devices, network interfaces, modems, disk storage systems, etc. The present invention is not limited to any one type of peripheral card and is meant to be used with many different types of peripheral cards.
The foregoing detailed description of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. The described embodiments were chosen in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US5490891 *||Dec 1, 1994||Feb 13, 1996||Duel Systems||Method of manufacturing a memory card package|
|US5502289 *||Mar 13, 1995||Mar 26, 1996||National Semiconductor Corporation||Stacked multi-chip modules and method of manufacturing|
|US5608606 *||Jun 14, 1994||Mar 4, 1997||Apple Computer, Inc.||Computer plug-in module and interconnection system for wireless applications|
|US5663901 *||Sep 12, 1995||Sep 2, 1997||Sandisk Corporation||Computer memory cards using flash EEPROM integrated circuit chips and memory-controller systems|
|US5736727 *||Jan 6, 1995||Apr 7, 1998||Nakata; Eiichi||IC communication card|
|US5933328 *||Jul 28, 1998||Aug 3, 1999||Sandisk Corporation||Compact mechanism for removable insertion of multiple integrated circuit cards into portable and other electronic devices|
|US6040622 *||Jun 11, 1998||Mar 21, 2000||Sandisk Corporation||Semiconductor package using terminals formed on a conductive layer of a circuit board|
|US6085412 *||Jun 12, 1998||Jul 11, 2000||Kabushiki Kaisha Toshiba||Method for manufacturing card type memory device|
|US6109939 *||Jun 2, 1998||Aug 29, 2000||Sony Corporation||Memory card and receptacle for same|
|US6151248 *||Jun 30, 1999||Nov 21, 2000||Sandisk Corporation||Dual floating gate EEPROM cell array with steering gates shared by adjacent cells|
|US6266724 *||Feb 1, 1999||Jul 24, 2001||Sandisk Corporation||Removable mother/daughter peripheral card|
|US6279114 *||Nov 4, 1998||Aug 21, 2001||Sandisk Corporation||Voltage negotiation in a single host multiple cards system|
|US6323064 *||Jan 4, 2000||Nov 27, 2001||Samsung Electronics Co., Ltd||Method for fabricating a memory card|
|US6333517 *||Jan 11, 2000||Dec 25, 2001||Nec Corporation||Semiconductor integrated circuit device equipped with power make-up circuit used in burn-in test after packaging and method for testing the same|
|US6410355 *||Jan 19, 2000||Jun 25, 2002||Sandisk Corporation||Semiconductor package using terminals formed on a conductive layer of a circuit board|
|US6445060 *||Aug 22, 2000||Sep 3, 2002||Micron Technology, Inc.||Coated semiconductor die/leadframe assembly and method for coating the assembly|
|US6456528 *||Sep 17, 2001||Sep 24, 2002||Sandisk Corporation||Selective operation of a multi-state non-volatile memory system in a binary mode|
|US6462273 *||Mar 16, 2001||Oct 8, 2002||Micron Technology, Inc.||Semiconductor card and method of fabrication|
|US6537842 *||Aug 30, 2001||Mar 25, 2003||Micron Technology, Inc.||Methods for fabricating protective structures for bond wires|
|US6726508 *||Dec 20, 2002||Apr 27, 2004||Tyco Electronics Amp K.K.||Card connector|
|US6733954 *||Mar 26, 2003||May 11, 2004||Nissha Printing Co., Ltd.||Semiconductor module substrate sheet, semiconductor module substrate sheet fabricating method and semiconductor module|
|US6843421 *||Aug 13, 2001||Jan 18, 2005||Matrix Semiconductor, Inc.||Molded memory module and method of making the module absent a substrate support|
|US7065656 *||Jul 3, 2001||Jun 20, 2006||Hewlett-Packard Development Company, L.P.||Tamper-evident/tamper-resistant electronic components|
|US7094633 *||Jun 23, 2003||Aug 22, 2006||Sandisk Corporation||Method for efficiently producing removable peripheral cards|
|US20040089717 *||Nov 13, 2002||May 13, 2004||Sandisk Corporation||Universal non-volatile memory card used with various different standard cards containing a memory controller|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US7170754 *||May 6, 2004||Jan 30, 2007||Sychip Inc.||SDIO memory and interface card|
|US7709278||Feb 26, 2007||May 4, 2010||Sandisk Corporation||Method of making PCB circuit modification from multiple to individual chip enable signals|
|US7778057 *||Feb 26, 2007||Aug 17, 2010||Sandisk Corporation||PCB circuit modification from multiple to individual chip enable signals|
|US7864540||Oct 31, 2007||Jan 4, 2011||Sandisk Corporation||Peripheral card with sloped edges|
|US7872483||Sep 4, 2008||Jan 18, 2011||Samsung Electronics Co., Ltd.||Circuit board having bypass pad|
|US7916512||Oct 12, 2007||Mar 29, 2011||Samsung Electronics Co., Ltd.||Memory module having high data processing rate|
|US7928010||Oct 20, 2006||Apr 19, 2011||Sandisk Corporation||Method for producing portable memory devices|
|US8013332 *||Oct 20, 2006||Sep 6, 2011||Sandisk Technologies Inc.||Portable memory devices|
|US8174861||Feb 25, 2011||May 8, 2012||Samsung Electronics Co., Ltd.||Memory module having high data processing rate|
|US8203355||Jun 19, 2012||Samsung Electronics Co., Ltd.||Circuit board having bypass pad|
|US8248093||Aug 21, 2012||Samsung Electronics Co., Ltd.||Circuit board having bypass pad|
|US8354749||Aug 4, 2006||Jan 15, 2013||Sandisk Technologies Inc.||Method for efficiently producing removable peripheral cards|
|US8446750||Oct 8, 2012||May 21, 2013||Samsung Electronics Co., Ltd.||Memory module using optical signal|
|US8488332 *||Sep 25, 2009||Jul 16, 2013||Fujitsu Limited||Function expansion device, manufacturing method thereof and electronic apparatus system|
|US8625323||Apr 23, 2012||Jan 7, 2014||Samsung Electronics Co., Ltd.||Memory module having high data processing rate|
|US8817511||Aug 16, 2010||Aug 26, 2014||Sandisk Technologies Inc.||PCB circuit modification from multiple to individual chip enable signals|
|US8917107||Jul 31, 2012||Dec 23, 2014||Samsung Electronics Co., Ltd.||Circuit board having bypass pad|
|US8972658 *||Aug 14, 2009||Mar 3, 2015||Nintendo Co., Ltd.||Game console and memory card|
|US9069036||Dec 12, 2013||Jun 30, 2015||Samsung Electronics Co., Ltd.||Circuit board having bypass pad|
|US20050248926 *||May 6, 2004||Nov 10, 2005||Moses Asom||SDIO memory and interface card|
|US20060267165 *||Aug 4, 2006||Nov 30, 2006||Sandisk Corporation||Method for efficiently producing removable peripheral cards|
|US20090305792 *||Dec 10, 2009||Nintendo Co., Ltd.||Game console and memory card|
|US20100079969 *||Sep 25, 2009||Apr 1, 2010||Fujitsu Limited||Function expansion device, manufacturing method thereof and electronic apparatus system|
|US20110315987 *||Dec 29, 2011||Warren Middlekauff||Portable memory devices|
|WO2008051838A2 *||Oct 19, 2007||May 2, 2008||Sandisk Corp||Portable memory devices and method therefor|
|U.S. Classification||361/679.31, 29/832, 29/593, 29/860, 361/679.01, 29/854, 174/250, 174/260|
|International Classification||G06K19/077, H05K1/02, H05K3/28|
|Cooperative Classification||H01L2224/73265, H01L2224/32225, G06K19/07732, H01L2224/48227, H01L2224/48091, Y10T29/49169, Y10T29/49004, H05K1/0268, H05K3/284, G06K19/077, H01L2924/1815, Y10T29/49179, H01L2224/32145, Y10T29/4913, H01L2924/01004, H01L2924/19041|
|European Classification||G06K19/077E7, G06K19/077, H05K1/02D2|
|Jul 17, 2003||AS||Assignment|
Owner name: SANDISK CORPORATION, CALIFORNIA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:TAKIAR, HEM P.;REEL/FRAME:014306/0015
Effective date: 20030714