Migrating 4 Kb/16 Kb/64 Kb F-RAM™ from DMOS5 to DMOS6 wafer parts - KBA218544

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    Question:

    What is DMOS5 to DMOS6 conversion of 4 Kb/16 Kb/64 Kb F-RAM™ parts? Why do ESD values differ in the datasheets for new DMOS6 parts from the datasheets for the DMOS5 wafer parts? Does this ESD value difference impact my current applications?

     

    Answer:

     

    DMOS5 to DMOS6 conversion of 4 Kb/16 Kb/64 Kb F-RAM parts

     

    The 4 Kb/16 Kb/64 Kb serial (SPI and I2C) F-RAMs are a two-die solution:

     

    • F-RAM core-die, which includes the F-RAM array and sense amplifier circuits
    • Logic-die, which includes the serial interface logic, I/O controls, I/O pads, and regulator circuits

     

    The migration from DMOS5 to DMOS6 is for the F-RAM core-die, while the logic-die remains identical to previous generation (DMOS5) parts. This migration is primarily to achieve the manufacturing of 4 Kb/16 Kb/64 Kb serial F-RAMs on an advanced 12-inch wafer facility without changing or optimizing any logic design or circuits. Therefore, the new DMOS6-based 4 Kb/16 Kb/64 Kb serial F-RAMs are form-factor and function-compatible to the existing DMOS5 parts.

     

    4 Kb/16 Kb/64 Kb F-RAM parts:

     

    I2C: FM24C04B, FM24CL04B, FM24C16B, FM24CL16B, FM24C64B, FM24CL64B

     

    SPI: FM25040B, FM25L04B, FM25L16B, FM25C160B, FM25640B, FM25CL64B

     

    ESD values in the new DMOS6 parts are different from previous generation DMOS5 wafer parts

     

    Even though DMOS6 wafer devices are identical to DMOS5 wafer devices in all aspects, you may notice differences in their ESD values for Human Body Model (HBM), Charged Device Model (CDM), and removed Machine Model (MM) specifications.

     

    The original 4 Kb/16 Kb/64 Kb serial F-RAMs on DMOS5 were built and qualified by Ramtron and integrated with Cypress after Ramtron’s acquisition in 2012. Migration from DMOS5 to DMOS6 is a fab transfer process by Cypress; therefore, all functionalities, parameters, and reliability specifications are requalified and revalidated to guarantee the DMOS6 part datasheet specifications. Cypress has performed component-level ESD tests on DMOS6 devices according to the JEDEC standard as follows:

     

    • HBM (JEDEC JESD22-A114-B) – Classification level 2: 2000V to < 4000 V; Cypress datasheet guarantees minimum 2 kV.
    • CDM (JEDEC JESD22-C101-A) – Classification level C2a (or 2a): 500 V to < 750 V; Cypress datasheet guarantees minimum 500 V.

     

    The JEDEC standard for the component-level ESD classification for HBM and CDM are shown in Table 1 and Table 2 respectively. Cypress does not test MM because JEDEC has discontinued the MM ESD test. DMOS 6 devices are tested for much higher limits for both HBM and CDM than shown in the respective part datasheets. The actual tested ESD voltage limits are available in the Qualification Test Plan (QTP) document attached to the product pages on www.cypress.com.

     

    Table 1. HBM ESD Component Classification Levels

                                                                                                                                      

    ClassificationVoltage Range (V)
    0A< 125
    0B125 to < 250
    1A250 to < 500
    1B500 to < 1000
    1C1000 to < 2000
    22000 to < 4000
    3A4000 to < 8000
    3B≥ 8000

     

    Reference: JEDEC/ESDA HBM (JESD22-A114F) 

     

    Table 2. CDM ESD Component Classification Levels

                                                                                                          

    ClassificationVoltage Range (V)
    C0a< 125
    C0b125 to < 250
    C1250 to < 500
    C2a500 to < 750
    C2b750 to < 1000
    C3≥ 1000

     

    Reference: JEDEC/ESDA CDM (JEDEC JESD22-C101F)

     

    Impact of ESD value difference on current applications

     

    DMOS5 to DMOS6 conversion is limited to the F-RAM core-die, which interfaces to the logic-die internally. None of its pads are bonded on any package pin in any form. All device pins in 4 Kb/16 Kb/64 Kb serial F-RAMs are bonded to the logic-die pads, which are unchanged in DMOS5 to DMOS6 conversion parts. Hence, the ESD protection circuits and their tolerance levels are identical between DMOS5 and DMOS6.

     

    As Table 1 shows, ESD HBM classification 2 defines the voltage tolerance limit > 2000 V up to 4000 V (4000 V excluded). Therefore, all components qualified within this voltage range are ESD HBM Class 2 qualified.

     

    Similarly, in Table 2, ESD CDM classification C2a (or 2a) defines the voltage tolerance limit of > 500 V up to 750 V (750 V excluded). Therefore, all components qualified for any value within this voltage range are ESD CDM Class 2a qualified.

     

    Figure 1. CDM Qualification Roadmap

     

    KBA218544 .png

    JEDEC provides a CDM qualification roadmap for various technology nodes, as shown in Figure 1. Because 4 Kb/16 Kb/64 Kb serial F-RAM devices are built on 130-nm technology node, a > 500 V CDM qualification falls within the JEDEC recommended limit for 130- nm technology.

     

    To conclude, ESD (HBM and CDM) datasheet parameters for products built in DMOS6 provide identical ESD performance and meet the JEDEC standard. To learn more about the ESD test results, refer to the Qualification Test Plan (QTP) document attached to the product pages on www.cypress.com.

     

    Reference: Industry Council - CDM Roadmap