What is claimed is:
1. A semiconductor memory production system comprising:
a wafer manufacturing line for manufacturing a plurality of semiconductor memory chips on a wafer using a plurality of kinds of wafer manufacturing equipment,
a wafer tester for testing the electrical characteristics of said chips;
a replacement address decision device for determining replacement addresses in a redundant memory section installed in said semiconductor memory based on the test results of said wafer tester; and
an estimation section for estimating the cause of failures based on results of statistical processing of said replacement addresses,
wherein wafer manufacturing equipment causing failures is identified in said wafer manufacturing line and the cause of the failures is removed.
2. A semiconductor memory production system according to claim 1, wherein said estimation section is provided with a defect distribution analyzer for generating a replacement address distribution based on said replacement addresses, and
a process defect estimation device for estimating process defects by comparing said replacement address distribution with previously stored defect distribution patterns.
3. A semiconductor memory production system according to claim 1, wherein there is provided a defect distribution analyzer for generating a replacement number for specific replacement addresses in said wafer.
4. A semiconductor memory production system according to claim 1, wherein there is provided a defect distribution analyzer for generating a history of said replacement number.
5. A semiconductor memory production system, wherein semiconductor memories manufactured on wafers are tested, the test results are statistically processed to infer the cause of failures, and the cause of the failures is removed from said wafer manufacturing equipment,
wherein there is provided a semiconductor test section that tests said semiconductor memories and outputs a bitmap showing the fail or pass judgment result for the address of each memory cell in a semiconductor memory,
a replacement address decision section that extracts the bit address of a fail bit from said bitmap and, based on this bit address, determines a replacement word line andor bit line address to be replaced with a redundant word line andor redundant bit line in a redundant memory section installed in said semiconductor memory and
an estimation section for estimating process defects by statistical analysis based on the replacement number of the exchanged word lines orand bit lines for each semiconductor memory, which is obtained based on said replacement addresses.
6. A semiconductor memory production system according to claim 1, wherein said estimation section is provided with a fuse address setting section for generating fuse addresses showing sections disconnected by fuses that set the addresses of the redundant word lines andor redundant bit lines for said replacement addresses, and
an extraction section for extracting a replacement number of the word lines andor bit lines exchanged for each semiconductor memory from said fuse addresses, and the distribution condition of each semiconductor memory chip for each wafer.
7. A semiconductor memory production system according to claim 1, wherein said estimation portion is provided with a pattern formation section that indicates each semiconductor memory chip on said wafer with a color or gradation corresponding to said replacement number.
8. A semiconductor memory production system according to claim 1, wherein said estimation section compares said replacement number pattern with replacement number patterns stored in advance, which are generated for each process anomaly, and based on the result of this comparison estimates a particular process anomaly.
9. A semiconductor memory production method comprising:
a wafer processing step for forming a semiconductor memory on a wafer through a plurality of processes;
a wafer testing step for testing said wafer in the wafer state to select non5 defective products;
a bit map outputting step for outputting, as a result of said testing, the addresses of memory cells of each semiconductor memory and a bit map showing the pass and fail determination of the addresses;
a replacement address decision step that extracts the bit address of a fail bit from said bitmap and, based on this bit address, determines a replacement word line andor bit line address to be replaced with a redundant word line andor redundant bit line in a redundant memory section installed in said semiconductor memory; and
a process defect estimation step for estimating process defects by statistical analysis based on the replacement number of the replaced word lines orand bit lines for each semiconductor memory, obtained based on said replacement addresses, or by the statistical analysis of the distribution states of the semiconductor memory in each wafer.
10. A semiconductor memory production method according to claim 9, wherein said process defect estimation step is provided with a fuse address setting section for generating fuse addresses showing sections disconnected by fuses that set the addresses of the redundant word lines and redundant bit lines for said replacement addresses, and
an extraction step for extracting a replacement number of the word lines and bit lines exchanged for each semiconductor memory from said fuse address, and the distribution state of each semiconductor memory chip for each wafer.
11. A semiconductor memory production method according to claim 9, wherein said process defect estimation step is provided with a pattern formation portion that indicates each semiconductor memory chip on said wafer with a color or gradation corresponding to said replacement number.
12. A semiconductor memory production method according to claim 9, wherein said process defect estimation step compares said replacement number pattern with replacement number patterns stored in advance, which are generated for each process anomaly, and based on the result of this comparison estimates a particular process anomaly.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A lens driving apparatus for a disk player for driving a lens holder in focus and tracking directions, said apparatus comprising said lens holder including an objective lens, focus coils, and tracking coils fixed thereto which is supported by a plurality of cantilevered wire-form elastic members, wherein:
said wire-form elastic members include inner circumferential side wire-form elastic members and outer circumferential side wire-form elastic members which are disposed to be apart from each other in said tracking direction so as to interpose therebetween a point of application of a focus driving force generated from said focus coils; and
said inner circumferential side wire-form elastic members and said outer circumferential side wire-form elastic members have respectively different spring constants when deflected in said focus direction, and have respectively different distances to said point of application in said tracking direction.
2. The lens driving apparatus for a disk player according to claim 1, wherein said spring constant of said inner circumferential side wire-form elastic members is greater than said spring constant of said outer circumferential side wire-form elastic members, and said distance from said inner circumferential side wire-form elastic members to said point of application is smaller than said distance from said outer circumferential side wire-form elastic members to said point of application.
3. The lens driving apparatus for a disk player according to claim 1, wherein said spring constants of said inner circumferential side wire-form elastic members and said outer circumferential side wire-form elastic members, and said distances to said point of application have a relationship of FiTiFoTo, wherein: Fi is said spring constant of said inner circumferential side wire-form elastic members; Ti is said distance from said inner circumferential side wire-form elastic members to said point of application; Fo is said spring constant of said outer circumferential side wire-form elastic members; and To is said distance from said outer circumferential side wire-form elastic members to said point of application.
4. The lens driving apparatus for a disk player according to one of claims 1 to 3, wherein said inner circumferential side wire-form elastic members and said outer circumferential side wire-form elastic members are formed by plate springs having the same thickness in said focus direction, and a width of each of said inner circumferential side wire-form elastic members in said tracking direction is greater than a width of each of said outer circumferential side wire-form elastic members in said tracking direction.
5. A lens driving apparatus for a disk player for driving a lens holder in focus and tracking directions, said apparatus comprising said lens holder including an objective lens, focus coils, and tracking coils fixed thereto which is supported by a plurality of cantilevered wire-form elastic members, wherein:
said wire-form elastic members include upper side wire-form elastic members and lower side wire-form elastic members which are disposed to be apart from each other in said focus direction so as to interpose therebetween a point of application of a tracking driving force generated from said tracking coils; and
said upper side wire-form elastic members and said lower side wire-form elastic members have respectively different spring constants when deflected in said tracking direction, and have respectively different distances to said point of application in said focus direction.