1、 JEDEC STANDARD DELPHI Compact Thermal Model Guideline JESD15-4 OCTOBER 2008 JEDEC SOLID STATE TECHNOLOGY ASSOCIATION NOTICE JEDEC standards and publications contain material that has been prepared, reviewed, and approved through the JEDEC Board of Directors level and subsequently reviewed and appro
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9、roduce a limited number of copies through entering into a license agreement. For information, contact: JEDEC Solid State Technology Association 3103 North 10th Street Suite 240 South Arlington, VA 22201-2107 or call (703) 907-7559 JEDEC Standard No. 15-4 -i- DELPHI COMPACT THERMAL MODEL GUIDELINE Co
10、ntents Page 1 Scope 1 2 Normative references 1 3 Definition of the DELPHI compact model 2 3.1 Overview 2 3.2 General criteria for compact models 3 3.3 The DELPHI methodology 3 3.4 The DELPHI compact model 3 4 Generating a DELPHI compact model 4 4.1 Summary of salient steps in the model generation pr
11、ocess 4 4.2 Validated detailed model 5 4.3 Defining the objective function 6 4.4 Defining training boundary condition set 7 4.5 Defining surface and internal nodes 8 4.6 Choice of optimization technique 10 4.7 Error estimate 11 5 Application considerations 11 5.1 Overview 11 5.2 Three-dimensional mo
12、deling and simulation tools 12 5.2.1. Overview 12 5.2.2. Conduction modelling tools 12 5.2.3. Computational Fluid Dynamics (CFD) tools 12 5.2.4. Representing a DELPHI compact model in 3D space 13 6 Distribution and Availability 15 7 Bibliography 15 Annex A - Table 1 - 38 boundary condition set 16 Fi
13、gures Figure 1 - Network compact model 4 Figure 2 - The DELPHI methodology 5 Figure 3 - The 38 boundary condition set 7 Figure 4 - Possible node topology for a PQFP package 8 Figure 5 - Partitioning the top surface of a QFP into two surface nodes 8 Figure 6 - Possible node partitioning of the top su
14、rface of a flip-chip BGA package 9 Figure 7 - Subdividing the leads node to handle asymmetric application environments 10 Figure 8 - Embedded DELPHI network 14 Figure 9 - Possible compact representation of a leaded package 14 JEDEC Standard No. 15-4 -ii- JEDEC Standard No. 15-4 Page 1 DELPHI COMPACT
15、 THERMAL MODEL GUIDELINE (From JEDEC Board Ballot JCB-08-26, formulated under the cognizance of the JC-15.1 Committee on Thermal Characterization.) 1 Scope This guideline specifies the definition and lists acceptable approaches for constructing a compact thermal model (CTM) based on the DELPHI metho
16、dology. The purpose of this document is twofold. First, it aims to provide clear guidance to those seeking to create DELPHI compact models of packages. Second, it aims to provide users with an understanding of the methodology by which they are created and validated, and the issues associated with th
17、eir use. The scope of this document is limited to single-die packages that can be effectively represented by a single junction temperature. The scope of the current document is also limited to steady state compact models. Dynamic compact models (which are necessary for simulating time-dependent beha
18、vior) are not covered. Boundary condition independence is a measure of the predictive capabilities of the model in application-specific environments. 2 Normative references The following normative documents contain provisions that, through reference in this text, constitute provisions of this standa
19、rd. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undate
20、d references, the latest edition of the normative document referred to applies. 1. JESD51, Methodology for the Thermal Measurement of Component Packages (Single Semiconductor Device), Dec. 1995. 2. JESD51-2, Integrated Circuits Thermal Test Method Environmental Conditions Natural Convection (Still A
21、ir), Dec. 1995. 3. JESD51-3, Low Effective Thermal Conductivity Test Board for Leaded Surface Mount Packages, Aug. 1996. 4. JESD51-5, Extension of Thermal Test Board Standards For Packages With Direct Thermal Attachment Mechanisms, Feb. 1996. 5. JESD51-6, Integrated Circuit Thermal Test Method Envir
22、onmental Conditions - Forced Convection (Moving Air), March 1999. 6. JESD51-7, High Effective Thermal Conductivity Test Board for Leaded Surface Mount Packages, Feb. 1999. 7. JESD51-8, Integrated Circuit Thermal Test Method Environmental Conditions Junction-to-Board, Oct. 1999. JEDEC Standard No. 15
23、-4 Page 2 2 Normative references (contd) 8. JESD51-9, Test Boards for Area Array Surface Mount Package Thermal Measurements, July 2000. 9. JESD51-10, Test Boards for Through-Hole Perimeter Leaded Package Thermal Measurements, July 2000. 10. JESD51-11, Test Boards for Through-Hole Area Array Leaded P
24、ackage Thermal Measurement, June 2001. 11. JESD15, Thermal Modeling Overview. 12. JESD15-1, Compact Thermal Modeling Overview. 13. JESD15-2, Terms and Definitions for Modeling Standards 1. 14. JESD15-3, Two-Resistor Compact Thermal Model Guideline. 3 Definition of the DELPHI compact model 3.1 Overvi
25、ew The DELPHI methodology was developed by the DELPHI Research Consortium, which completed a 3-year research project from 1993 to 1996. The project was partially funded by the European Community under ESPRIT III Contract # 9197. The results of the Consortiums investigation into compact package model
26、s is non-proprietary and in the public domain. The consortium proposed a methodology for the generation of compact models with a high degree of boundary condition independence. This methodology is documented in a comprehensive report published by the consortium as well as a number of technical journ
27、als and conference proceedings that are available in the literature (see Bibliography). The fundamental vision that underlies compact thermal models is the principle of division of responsibility. It is the responsibility of the CTM supplier to characterize the part, whereas the end-user must specif
28、y the environment that defines the application. Thus the CTM supplier then becomes responsible for supplying a properly characterized model of the component. The concept of “a properly characterized model” is tied to a metric of boundary condition independence (BCI). This metric is defined as the BC
29、I Index. A discussion of the BCI concept is available. An additional metric is also defined for the accuracy of a CTM over sub-ranges of boundary conditions relevant to specific application environments. This metric is known as the boundary condition subset (BCS) Index. 1)To be published. JEDEC Stan
30、dard No. 15-4 Page 3 3.2 General criteria for compact thermal models A compact thermal model should fulfill the following criteria. It should be of limited complexity. In todays technology, this equates to tens of nodes. It is conceivable that this number could increase over time with improvements i
31、n computer calculating power and the sophistication of CTM techniques. It should satisfy appropriate levels of boundary condition independence (BCI). BCI is a property of a CTM whereby it accurately calculates a chip temperature in a variety of application environments, which, in essence, impose dif
32、ferent boundary conditions on the component. It is a goal of the CTM standardization effort that CTMs should demonstrate a high level of BCI. It should be vendor and software neutral. A CTM generation technique should be adaptable to standard conduction codes for performing a package-level thermal a
33、nalysis. The CTM should be capable of insertion into standard numerical codes for system-level analysis. It should be fully documented and non-proprietary. 3.3 The DELPHI methodology The following are the key features of the DELPHI methodology. The compact model is generated from analysis, and not t
34、esting. Experiments are relevant for validation purposes only. The starting point for the process is the availability of an experimentally validated detailed thermal model (see 4.2). The analytical procedure used to derive the compact model involves a statistical process of optimization. The model d
35、oes not contain any artifacts from the environment. Error estimate is an intrinsic part of the model generation process. Like the other compact model approaches, the DELPHI approach masks data about the package that the CTM supplier may regard as proprietary. 3.4 The DELPHI compact model A DELPHI co
36、mpact model is a thermal resistance network. The DELPHI thermal resistance network is comprised of a limited number of nodes connected to each other by thermal resistor2)links (see Figure 1). In effect, the complex 3D heat flow within a real package is represented by a series of links. Network nodes
37、 are, by definition, each associated with a single temperature only. The nodes can be either surface or internal. Surface nodes are associated with a physical region of the package surface defining the area of the node. In such a case, the nodal temperature represents the average temperature of the
38、area allocated to the node in the actual package. Also, surface nodes must always have a direct one-to-one association with the corresponding physical areas on the actual package. Therefore, it is critical that they communicate with the environment in the same manner as the package. 2)The thermal re
39、sistors in a DELPHI model are mathematical constructs. They have the units of C/W, but the presence of a thermal resistance between any two surface nodes in the thermal network does not necessarily imply that this corresponds to the actual physical resistance between those two points in the package.
40、 JEDEC Standard No. 15-4 Page 4 3.4 The DELPHI compact model (contd) Internal nodes lie within the package body and may or may not correspond to a physical region within the package. The predicted node temperature has no physical meaning for those internal nodes that do not correspond to actual regi
41、ons within a package. Surface nodes communicate with internal nodes as well as the surrounding environment. Internal nodes do not communicate with the environment directly; however they may have a heat source associated with them. Figure 1 Network Compact Model 4 Generating a DELPHI compact model 4.
42、1 Summary of salient steps in the model generation process The various steps that comprise the DELPHI compact model generation methodology are outlined in more detail below, and in Figure 2. Step 1: Ensure that a validated detailed model is available. Step 2: Define the objective function that is to
43、 be minimized during the optimization. Step 3: Define training and test boundary conditions sets in terms of heat transfer coefficient values. Step 4: Define number and locations of surface and internal nodes. Step 5: Simulate detailed model under training and test boundary conditions to generate he
44、at flux and temperature data. Step 6: Choose appropriate statistical optimization technique. Step 7: Execute optimization using training boundary condition set. Step 8: Define error estimation method. Step 9: Generate error estimate (backfit) using test boundary condition set. Step 10: Make compact
45、model available for dissemination in neutral file format. Junction (heat source)Top Inner Top OuterBottom Inner Bottom OuterLeadsThermal Resistors JEDEC Standard No. 15-4 Page 5 4 Generating a DELPHI compact model (contd) Validated Detailed Model AvailableDefine Objective FunctionDefine Number and L
46、ocations ofSurface and Internal NodesDefine Training and Test Boundary Condition Sets. Run Detailed Modelfor these sets.Choose StatisticalOptimization TechniqueProvide Information on Model AvailabilityGenerate Compact Model inNeutral File FormatDefine Error Estimation MethodGenerate Error EstimateUs
47、ing Test B.C. SetExecute OptimizationUsing Training B.C. SetFigure 2 The DELPHI Methodology 4.2 Validated detailed model A detailed thermal model or detailed model of a package is a numerical model that attempts to reproduce the physical geometry and material properties of the package in as exact a
48、manner as necessary in order to predict temperatures and fluxes to a sufficient degree of accuracy at any point within the package. The methodology for the generation of a detailed model is outside the scope of this document. The generation of such models is partially dependent on the capabilities o
49、f the software environment available to the user and user preferences in modeling methodologies. The DELPHI methodology assumes that a validated detailed model of the package is available, and has been validated under well-defined or “hard” boundary conditions, or otherwise, in a manner acceptable to the CTM supplier. JEDEC Standard No. 15-4 Page 6 4.3 Defining the objective function The objective function in this methodology is defined as the discrepancy between the detailed model and prediction from the compact model summed over both the training bou
