1、 JEDEC PUBLICATION Guideline for Internal Gas Analysis for Microelectronic Packages JEP144A (Revision of JEP144, July 2002) NOVEMBER 2011 JEDEC SOLID STATE TECHNOLOGY ASSOCIATION NOTICE JEDEC standards and publications contain material that has been prepared, reviewed, and approved through the JEDEC
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10、 Publication No. 144A -i- GUIDELINE FOR INTERNAL GAS ANALYSIS FOR MICROELECTRONIC PACKAGES CONTENTS Page Foreword ii 1 Scope 1 2 Need for Internal Gas Analysis 1 3 Selecting an Internal Gas Analysis analytical service lab 2 4 Process of conducting an Internal Gas Analysis 2 5 Interpreting the Intern
11、al Gas Analysis results 5 6 Process control 8 ANNEXES A Common failure mechanisms 9 B Laboratory selection checklist 11 C Alternatives to Internal Gas Analysis 13 D Compendium of references to Internal Gas Analysis 19 E Differences between JEP144A and JEP144 27 JEDEC Publication No. 144A -ii- Forewo
12、rd The measurement of the moisture levels and other gases in hermetically sealed microcircuit packages is one of the key steps in demonstrating the robustness of the manufacturers materials and sealing processes and the reliability of products. The manufacturer must be in control of all of parts, pr
13、ocesses, materials, and process byproducts that can affect the internal package atmosphere to be confident that the products are in compliance with the relevant requirements. The manufacturer needs to understand the effects that moisture and other gases can have on the reliability of the product. Mo
14、isture is a primary importance to the reliability and but so are other gases. Control of hermetic environments in microelectronic devices is very useful for process control monitoring and long term reliability of the product. In addition, knowledge about the presence of other gases can provide clues
15、 to help process engineers improve and control their processes. Other gases may indicate, for example, that the internal materials may not be stable for long term use and that the internal atmosphere may be changing over time and temperature, often creating additional moisture in the device atmosphe
16、re thru chemical reaction or outgassing, Other gases may also provide evidence that the devices may not actually be hermetic. This is an excellent tool to validate the effectiveness of leak test procedures and package survival to mechanical and thermal stress. Users should keep in mind that the test
17、 results for Internal Gas Analysis reflect the gas in the internal atmosphere of the device at the time of test. Devices (particularly those containing organic materials or those with measurable leak rates) do not necessarily have a fixed (or correct) result. Test results can be a function of the hi
18、storical environmental exposure of the device. Internal Gas Analysis technology is used by many disciplines. It is best known for its use as a Military Standards Qualification test in accordance with MIL-STD-883, Method 1018, for moisture content. It is also useful as a process control tool, a proce
19、ss validation tool, materials outgassing studies, and as a failure analysis tool. Numerous analytical methods can be employed to measure the composition of gasses contained in a semiconductor package. GC-Mass Spectrometry, Mass Spectrometry, and various single purpose sensors and techniques to measu
20、re moisture are available. In order to make effective use of these methods, the precision, accuracy, and sensitivity of each measurement system must be validated. The ability to measure the gasses contained in a hermetic package from 0.0002 cc to packages over 200 cc (no upper limit on size) is avai
21、lable at test laboratories approved by Defense Logistics Agency (DLA) Land and Maritime, Columbus, Ohio in accordance with MIL-STD-883, Method 1018, for product compliant to military specifications. JEDEC Publication No. 144A Page 1 GUIDELINE FOR INTERNAL GAS ANALYSIS FOR MICROELECTRONIC PACKAGES (F
22、rom JEDEC Board Ballot JCB-11-54 and JCB-11-68, formulated under the cognizance of the JC-13 Committee on Government Liaison.) 1 Scope This guideline is applicable to hermetically sealed microelectronic components (including discrete semiconductors, monolithic and hybrid microcircuits). Specific cas
23、es with unique packaging, materials, or environmental constraints may not find all of the following information and procedures applicable. A compendium of references to reports, papers, and texts, relating to internal gas analysis, volatile gasses, and sealed packages is included in Annex D. This gu
24、ideline describes how to select a lab, the internal gas analysis testing process, and the interpretation of the test results. Lists of common failure mechanisms can be found in Annex A. A brief discussion of process characterization and process control is included. Annex C contains supplemental meth
25、ods for measuring moisture content along with their advantages and disadvantages. 2 Need for Internal Gas Analysis The presence of moisture and other gases in hermetically sealed microcircuit packages continues to be a concern for electronic component manufacturers and their customers. Reports indic
26、ate that moisture can lead to internal corrosion of component metallization and electrical connections; moisture induced metal migration can lead to shorts; and high current leakage can be caused by moisture on internal electronic surfaces, such as substrates. The causes of moisture in a hermetic pa
27、ckage can be traced to the package seal, internal construction materials, the processes used to manufacture the device and stresses incurred during subsequent screening tests, such as burn-ins or thermal cycling. Consequently, it is important for the manufacturer to understand to what degree each of
28、 the potential contributors of moisture may impact their product. Internal gas analysis is a means by which the manufacturer can obtain information about the packages, materials, processes, and screening used with the products to ultimately gain better control over the final results. Users should re
29、member that a failure due to moisture usually occur in low temperature, unlike most other failure mechanisms that are results of high temperature processes. Production lots where most or all of the devices have high moisture have the potential to create numerous device failures. Moisture related fai
30、lures are not usually found at initial operational testing. Failures tend to occur later in time, often several years later when the systems are in the field. NOTE Not all semiconductor devices have failure modes which are related to “high” moisture concentrations. Devices should be characterized th
31、rough accelerated life testing in humid environments to assess the potential for moisture related failure mechanisms. Other gasses such as Hydrogen or Oxygen can be detrimental to the performance and/or reliability of a device. Characterizing a devices failure modes relative to gas mixtures is an im
32、portant step in the interpretation of Internal Gas Analysis data. JEDEC Publication No. 144A Page 2 3 Selecting an Internal Gas Analysis analytical service lab Laboratory selection is one of the most important decisions to be made in the internal gas analysis process. The manufacturer must have conf
33、idence in the laboratorys ability to perform the required procedures accurately and repeatedly. When a good working relationship is established with a laboratory, the manufacturer can build a database of internal gas analysis results that can be used as a metric for the stability of the processes. M
34、any of the users requirements can be met by selecting a lab that has received certification for performing internal gas analysis from the by DLA Land and Maritime. This is frequently a contractual requirement. A checklist for lab selection can be found in Annex B. The facility and the way that it is
35、 operated must match the needs of the user of its services. The way that the lab operates, i.e., business/technical aspects of the lab should be compatible with the users needs and expectations. The lab should be able to explain its methodology for performing the tests and interpret the test results
36、 to the users satisfaction. The user needs to ensure that the products submitted for internal gas analysis will be properly handled and not mistreated in a way that could compromise the results of the analysis. This is particularly true of packages with thick walls or lids that must be “thinned” in
37、order to open them in the analytical apparatus. The lab should have experience performing the internal gas analysis on packages of the same size and type as the prospective users. When parts are being tested to demonstrate conformance to a specification, the test report should clearly indicate which
38、 measured gasses are being evaluated for purposes of specification conformance. The applicable specification/document number, and the allowable limit, as required, for each gas in that specification should be listed in the report. If the specification is provided by the user, a laboratory analysis s
39、ubmission form should clearly identify the requirements of the specific test. 4 Process of conducting an internal gas analysis Prior to submitting the devices to internal gas analysis, it is recommended that the user submit the samples to fine and gross leak testing in accordance with MIL-STD-883, M
40、ethod 1014, to verify the integrity of the hermetic package. Note: Air equivalent leak rates of less than 3E-10atm-cc/sec are needed to prevent moisture ingress or to prevent significant gas exchanges from taking place. Internal gas analysis testing requires a number of pieces of equipment. These in
41、clude a mass spectrometer, moisture dew point analyzer, package opening system, mercurial barometer, pressure gauges, pre-bake oven, small grinding tool, and calibration gasses, including nitrogen gas, room air, and certified mixes typical of the manufacturing processes used for the devices to be te
42、sted. Gasses typically found in an internal gas analysis include water vapor, oxygen, nitrogen, carbon dioxide, argon, helium, hydrogen, perfluorocarbons, methane, pump oil, and other organic compounds. Some procedures require confirmation of the hermeticity of the package prior to starting the test
43、. It is recommended that any hermeticity measurements be made after any mechanical alterations to the test package. JEDEC Publication No. 144A Page 3 4 Process of conducting an internal gas analysis (contd) A mass spectrometer for internal gas analysis should be capable of detecting the gasses of in
44、terest, and as a minimum, should include the gasses specified in Mil-Std 883, Method 1018. The package opening system has a piercing device that operates from inside an opening chamber or transfer passage. The piercing device must be able to pierce a sample package without otherwise damaging the pac
45、kage seal or breaking the mass spectrometer chamber vacuum. Due to the piercing of the package, this is a destructive test. This system must be able to handle a variety of package sizes and shapes, and should be able to hold the devices in place to allow for proper transfer of the gasses to the mass
46、 spectrometer. The opening chamber and transfer passage must be capable of maintaining a vacuum and a constant temperature. Calibration is necessary for all of the equipment used in the internal gas analysis testing procedure. The National Institute of Standards and Technology (NIST) has specific pr
47、ocedures for calibration of the gas analyzer. MIL-STD-883, Method 1018 (latest revision) for internal water-vapor content testing, for example, requires that the moisture dew point analyzer be calibrated at least once per year. Also mentioned in Method 1018 is the calibration of the mass spectromete
48、r, which is performed using a package simulator capable of providing three known volumes of gas to use as calibration points. Periodic calibrations are needed for equipment used to measure hermeticity, pressure, and temperature Calibrated thermocouples should be used when checking the oven temperatu
49、re and transfer passage temperature. The pre-bake oven stability should be checked to ensure that the temperature over a 24-hour period is held at 100 C, +/-5 C. Often a multi-point profile of 5 or 9 points is used, depending on how many shelves of an oven are used. A number of daily calibration records also need to be maintained. These include the calibration coefficients and factors for gasses including moisture and other independent variables, such as, sample gas volume, and calibrated moisture level. Ceramic packages may need to have the lid thinned, by grinding for example, t
