Method and system for tracking manufacturing data for integrated circuit parts

[0002] This invention relates to integrated circuits, and more particularly to a system and method for tracking integrated circuit parts through the manufacturing process.

[0003] In the manufacturing of integrated circuit parts (“IC parts”), a wafer consists of several hundred die. A set of wafers is grouped together and called “lots”. At each step of manufacturing, a lot is processed and the resulting data about the lot can be stored in a database. Ideally, lots proceed through the manufacturing process together so that the database of information can be useful in analyzing problems or defects in specific lots.

[0004] Unfortunately, in the real world, wafers can get separated from their lots and placed in new lots. During some steps, lots can be subdivided or combined into larger lots. Since lots do not remain static, it is a very tedious procedure to reconstruct all information gathered about a particular lot of wafers. In addition, with the movement of wafers among lots, the integrity of the lot data is jeopardized since the data for a lot may be inaccurate or incomplete.

[0005] Providing a method or system for tracking IC parts individually, regardless of their movement among various lots would produce a more accurate, detailed, and useful database.

[0006] Such a system would enable the entire manufacturing process to become much more productive with respect to the use of equipment and personnel by IC parts being allowed to flow through processes without trying to keep the original lots grouped in a meaningful order. Trying to keep lots grouped for the purpose of data analysis can waste much time. The lots go through different steps and get split up based on performance, causing the lots to continually decrease in size. Because it is a much more beneficial use of assets to work with large quantities of parts than many small groups, it is advantageous to move IC parts with no regard to their original lots. A system which would allow free movement of IC parts while retaining the ability for data analysis would make the manufacturing of IC parts more efficient.

[0007] The present invention solves the above-mentioned problems in the art and other problems which will be understood by those skilled in the art upon reading and understanding the present specification. The present invention provides an apparatus and method for tracking data for individual integrated circuits through the manufacturing process by programming an individual part identifier into a non-volatile portion of the integrated circuit and maintaining a database of all manufacturing step statistics for later review and analysis. Typical uses for this data is in the review of the process steps used in producing particular lots of wafers of memory chips and tracking failure rates according to lot and wafers numbers.

[0008] In the drawings, where like numerals refer to like components throughout the several views,

[0009] FIG. 1 is a block diagram of a computer system connected to a IC parts processor;

[0010] FIG. 2 is a block diagram of an IC part;

[0011] FIG. 3 is a flowchart of the method of the IC parts data summary;

[0012] FIG. 4 is a flowchart of an alternate method of gathering and tracking statistics for IC parts,; and

[0013] FIG. 5 is a flowchart of a method for gathering, tracking and using statistics for IC parts.

[0014] In the following Detailed Description, reference is made to the accompanying drawings which form a part hereof and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice and to use the invention, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the spirit and scope of the present invention. The following Detailed Description is, therefore, not to be taken in a limiting sense and the scope of the invention is defined by the appended claims. In the figures, elements having the same number perform essentially the same functions.

[0015] A computer system 100 as shown in FIG. 1 has a central processing unit (“CPU”) 105 and a memory 110. Computer system 100 is coupled to a integrated circuit parts processor 115 by data bus 120. Computer system 100 can be a Sun workstation, available from Sun Microsystems of Palo Alto, Calif., or another general purpose computer. Memory 110 can be RAM, a disk or floptical drive, or another form of primary or secondary computer storage. Data bus 120 can be a serial or parallel cable, any time of computer network, or other data transfer mode. IC parts processor 115 can be any fabrication, probe or test machine used in the manufacturing or testing of semiconductors.

[0016] FIG. 2 is an integrated circuit part 200. IC part 200 can be a memory device such as a DRAM. A plurality of IC parts 200 can be combined and used to form memory modules. Such a memory module can be a Dual In-Line Memory Module (“DIMM”), a Single In-Line Memory Module (“SIMM”), or a Multi-Chip Module (“MCM”), or other such uses. In the alternative, IC part 200 can be used in a computer system for SRAM caching, various types of FLASH memory, SSRAM, PROM, EEPROM, etc.

[0017] Whatever the type of IC part 200, it contains a memory array 205 as well as a plurality of nonvolatile memory elements 210. These nonvolatile memory elements 210 may be antifuses, laser fuses, electrical fuses, FLASH memory cells, FERAM memory cells, or any other type of nonvolatile memory cell. Such nonvolatile memory elements 210 are well known in the semiconductor processing industry.

[0018] The nonvolatile memory elements 210 of IC part 200 can be used to store data relating specifically to the individual IC part 200. For example, such use of the nonvolatile memory elements 210 is described in “A STRUCTURE AND A METHOD FOR STORING INFORMATION IN A SEMICONDUCTOR DEVICE,” by Zheng et al. U.S. patent application Ser. No. 08/664,109, now U.S. pat. No. 5,895,962, as well as “METHOD AND APPARATUS FOR STORAGE OF TEST RESULTS WITHIN AN INTEGRATED CIRCUIT,” by Debenham et al., U.S. patent application Ser. No. 08/591,238, now abandoned the details of which are incorporated by reference.

[0019] There are many uses for storing data relating to the individual IC part 200 in its nonvolatile memory elements 210. As is discussed by Debenham et al., after an IC part 200 is tested, one of the nonvolatile memory elements 210 can be used to indicate completion of the test. In this manner, the nonvolatile memory elements 210 can be read to verify that IC part 200 has indeed completed a previous test before proceeding to a subsequent test.

[0020] Instead of storing test results directly on IC part 200, the present invention uses the nonvolatile memory elements 210 to store a part identifier on each IC part 200. The part identifier is retrieved from IC part 200 during the various processing steps of fabricating, probing, and testing the IC part 200. Results from the processing steps can be stored in a computer database. By using a part identifier specific to individual IC parts, the present invention can reconstruct data summaries of like IC parts in any step that manufacturing that has access to these identifiers.

[0021] The flowchart of the method of the present invention is shown in FIG. 3. For illustrative purposes, FIG. 3 describes the invention as implemented on a IC parts tester, which corresponds to IC Parts Processor 115 shown in FIG. 1. The invention can also be implemented on any other IC parts processor used throughout the fabrication, probing, and testing steps.

[0022] In the method shown by the flowchart, a plurality of IC parts 200 are loaded on the tester at step 305 of FIG. 3. The tester reads the part identifiers at step 310 from each of the loaded IC parts 200. Testing proceeds at step 315 and data from the testing is collected and stored in a computer database in the memory 110 of computer system 100. If there are more IC parts 200 that need testing, then the procedure repeats at step 325. Again, this method of tracking data for individual IC parts 200, as shown in FIG. 3, can be implemented on all of the machines used throughout the manufacturing process.

[0023] Once a database is generated by the fabrication, testing, and probing of IC parts 200 by the various IC parts processors 115, computer system 100 can be used to analyze and report data specific to individual IC parts 200. The database stored in computer system 100 can be sorted to reconstruct data summaries of parts that all began manufacturing together, or that have other similar characteristics.

[0024] In another embodiment, the data may be fed to the computer processor 100 from parts processor 115 in real time, as shown in FIG. 4. The process shown in FIG. 4 is identical to the process shown in FIG. 3 except for the sending of data to the computer 100 at step 320 is performed for each IC processed.

[0025] Also shown in FIG. 4 are the steps for associating the data with the part identifiers. This association, performed by computer 100, may be used to gather and track statistics based on lot, wafer or individual parts. The statistics may show, by way of example and not by way of limitation, trends in failures of parts of a particular lot, types of failures in processing of wafers based on process variations, etc. Those skilled in the art will readily recognize that a wide variety of information may be tracked and associated with each integrated circuit or memory device without being limited to the size of the non-volatile memory on the individual circuits.

[0026] Although specific embodiments have been illustrated and described wherein, it will be appreciated by those of ordinary skill in the art that any arrangement which is calculated to achieve the same purpose may be substituted for the specific embodiments shown. This patent is intended to cover any adaptations or variations of the present invention. Therefore, it is manifestly intended that this invention be limited only by the claims and the equivalents thereof.