This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2005-133631, filed Apr. 28, 2005, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a processing device on which processing elements having the same function are embedded in one chip.
2. Description of the Related Art
In a processing device such as a microprocessor, the attention has been drawn to a new technology for enhancing the processing capability by disposing plural processing elements having the same function in one chip, and operating these plural processing elements in parallel. According to this technology, an appropriate processing device can be provided in a short period depending on the type of the system by determining the number of processing elements at the time of designing.
In such a processing device, even if there is one defective processing element which does not operate normally in a chip, use of the defective block is prohibited, and only normally operating processing elements are functioned and the chip is approved as a conforming product, for the purpose of enhancing the yield of conforming products. This is known as logic redundancy technology.
In the logic redundancy technology, however, leak current of a defective block is a bottleneck for reduction of power consumption. That is, since supply voltage is applied to a defective block which is not practically used, the electric power consumed in the processing device is enormous if power short defect is occurring in the defective block.
In the field of semiconductor memory, on the other hand, a fuse element is connected between a power line and a memory block, and if the memory block is defective, the fuse element is cut off, so that supply voltage is not applied to the memory block, which is known as power isolation technology.
However, the power isolation technology is a technology effective in a circuit of small current consumption such as a semiconductor memory, and cannot be applied to a circuit of larger current consumption as compared with a semiconductor memory, such as a logic circuit including a processing device. This is because, when a fuse element is connected between a power line and a processing element, operation of the processing element is disturbed due to voltage drop of the fuse element (resistive element).
A processing device according to a first aspect of the invention comprises first and second processing elements having the same function, first and second power lines which are disconnected each other and which are provided on the first and second processing elements respectively, and a power source terminal which is provided on the first processing element and which is connected to the first processing element and the first power line, wherein a power source terminal is not provided on the second processing element.
A processing device according to a second aspect of the invention comprises first and second processing elements having the same function, first and second power lines which are disconnected each other and which are provided on the first and second processing elements respectively, and a package having a power source terminal, wherein the power source terminal is provided on the first processing element and which is connected to the first processing element and the first power line, wherein a power source terminal of the package is not provided on the second processing element.
A processing device according to a third aspect of the invention comprises first and second processing elements having the same function, first and second power lines which are disconnected each other and which are provided on the first and second processing elements respectively, and a package having a power source terminal and a power source plate commonly used among the first and second processing elements, wherein the power source terminal is provided on the first processing element and which is connected to the first processing element and the first power line, wherein a power source terminal of the package is not provided on the second processing element.
An aspect of the present invention will be described below in detail with reference to the accompanying drawing.
1.
A chip 10 houses a controller, and plural processing elements (processing elements) PE0, PE1, PE2, PE3 having the same function. The controller functions, for example, as a central processing unit (CPU), and the plural processing elements PE0, PE1, PE2, PE3 function, for example, as signal processors.
Herein, if at least one of the plural processing elements PE0, PE1, PE2, PE3 fails to operate normally, three measures are considered, that is, A. the chip 10 is rejected, B. saved by logic redundancy technology, and C. modified as a conforming product of different specification.
The logic redundancy technology of B is a technology of, in the case where specification is set to a processing device having three processing elements, disposing three processing elements and one or more redundancy block (processing element) in the chip 10, thereby saving the chip 10 as a conforming product even if a defective block NG occurs.
To modify as a conforming product in C is a technology of saving the chip 10 as a conforming product by changing the specification of the chip 10 depending on the number of normally operating processing elements even if a defective block NG occurs, unless all the processing elements are defective, and applying to an application suited to the specification.
An aspect of the present invention proposes a technology for completely preventing leak current in a defective block NG in a processing device saved by such logic redundancy technology or modification.
In the aspect of the present invention, accordingly, a new configuration is employed, in which part or all of routes for feeding supply voltage to plural processing elements are provided independently in each block, and the feeding route of supply voltage is cut off with respect to a defective block NG without adding a new element such as a fuse element. In this case, supply voltage is fed to normal processing elements, and supply voltage is not fed to defective blocks NG, so that leak current in the defective blocks NG can be prevented completely.
The position for cutting off the feeding route of supply voltage is any one of (1) a chip terminal (bump), (2) a chip side terminal (pad) of a package 11, and (3) a printed circuit board (PCB) side terminal (bump) of the package 11, as shown in
2. Some of the best modes of carrying out the invention will be described below.
A first embodiment of the invention relates to a processing device in which presence or absence of cutting of a feeding route of supply voltage is set in each processing element in chip terminals (bumps).
A. Configuration
A chip 10 houses a controller, and plural processing elements PE0, PE1, PE2, PE3 having the same function. As a result of an operation test, suppose the processing element PE0 is determined to be defective block NG out of the plural processing elements PE0, PE1, PE2, PE3.
Chip terminals (bumps) 12 are disposed on the chip 10. The chip terminals 12 disposed on the processing elements PE0, PE1, PE2, PE3 are power source terminals for feeding supply voltage (VDD or VSS), and are provided independently for each of the processing elements PE0, PE1, PE2, PE3.
However, as for the processing element PE0 determined to be a defective block NG, the chip terminal 12 is not disposed on the processing element PE0 in order to cut off feed of supply voltage to the processing element PE0.
The chip terminals 12 on the controller are power source terminals for feeding supply voltage to the controller 12, and chip terminals 12 provided on the edge of the chip 10 are input/output (I/O) terminals for use in input and output of data.
Even in the case where the chip terminal 12 is not disposed on the processing element PE0 which is a defective block NG, supply voltage is fed into the defective block NG if the power line is shared among circuit blocks including the controller and processing elements PE0, PE1, PE2, PE3 formed in the chip 10.
Accordingly, as shown in
That is, the power line is closed within one circuit block, for example, within the processing element PE0. Therefore, supply voltage fed to one circuit block will never flow into other circuit blocks.
On one side of the package 11, PCB side terminals (bumps) 13 are disposed in an array. On the other side of the package 11, a recess for mounting the chip 10 is provided, and chip side terminals (pads) 14 are disposed in an array in the recess corresponding to the chip terminals 12.
In the package 11, the chip side terminals 14 are disposed also in the positions corresponding to the processing element PE0. That is, as for the package 11, for example, a universal package can be used so that a power source plate is commonly used among all the processing elements PE0, PE1, PE2, PE3, and therefore, the manufacturing cost of the product can be lowered.
However, as shown in
The package explained herein is merely an example, and the example of the invention is not limited to the type of the package, but can be applied in various forms of package.
According to this configuration, supply voltage to a defective block can be cut off only by independent connection of the power line and modification of layout of the chip terminals, so that leak current in a defective block can be prevented completely. Besides, since a fuse element is not used in cutting of supply voltage, there is no problem of malfunction of the circuit blocks due to voltage drop.
B. Modified Examples
FIGS. 7 to 9 show modified examples of the chip of the first embodiment.
Similarly, as shown in
Even if two or more of the processing elements PE0, PE1, PE2, PE3 are defective blocks NG, the same effects as in the first embodiment are obtained unless the chip terminal 12 is disposed on these defective blocks NG.
C. Manufacturing Method
First, after forming circuit blocks such as a controller and processing elements on the chip, the operation of these circuit blocks is tested. This operation test is intended to check the functions of the circuit blocks by bringing a tester probe into contact with the pads on the chip (step ST1).
Depending on results of the operation test, layout of chip terminals (bumps) is selected. For example, when the processing element PE0 is determined to be defective, a layout in which no chip terminal exists on the processing element PE0 is selected, and chip terminals are formed in this layout (step ST2).
Finally, by packaging for mounting the chip on the package, the processing device of the first embodiment is obtained (step ST3).
D. Others
In the first embodiment, by cutting off supply voltage (VDD or VSS) to at least one of defective blocks, the purpose of preventing leak current is achieved. The first embodiment is also applicable in the case of using three or more supply voltages (VDD1, VDD2, . . . VSS).
The first embodiment has an effect of preventing leak current in a defective block of a processing device having plural processing elements.
A second embodiment of the invention relates to a processing device in which presence or absence of cutting of a feeding route of supply voltage is set in each processing element in chip terminals (bumps) of package.
A. Configuration
A chip 10 houses a controller, and plural processing elements PE0, PE1, PE2, PE3 having the same function. In the same manner as in the first embodiment, suppose that, as a result of an operation test, the processing element PE0 is determined to be a defective block NG, out of the plural processing elements PE0, PE1, PE2, PE3.
Chip terminals (bumps) 12 are disposed on the chip 10. The chip terminals 12 disposed on the processing elements PE0, PE1, PE2, PE3 are power source terminals for feeding supply voltage (VDD or VSS), and are provided independently for each of the processing elements PE0, PE1, PE2, PE3.
In the second embodiment, however, the chip terminal 12 is also disposed on the processing element PE0 determined to be a defective block NG.
The chip terminals 12 on the controller are power source terminals for feeding supply voltage to the controller 12, and chip terminals 12 provided on the edge of the chip 10 are I/O terminals for use in input and output of data.
A power line (VDD or VSS) is provided independently in each circuit block disposed in the chip 10 in the same manner as in the first embodiment. That is, the power line is closed within one circuit block, for example, within the processing element PE0, and therefore, supply voltage fed to one circuit block will never flow into other circuit blocks.
On one side of the package 11, PCB side terminals (bumps) 13 are disposed in an array. On the other side of the package 11, a recess for mounting the chip 10 is provided, and chip side terminals (pads) 14 are disposed in an array in the recess corresponding to the chip terminals 12.
However, as shown in
Therefore, supply voltage will never be fed to the processing element PE0.
The package explained herein is merely an example, and the example of the invention is not limited to the type of the package, but can be applied in various forms of package.
According to this configuration, supply voltage to a defective block can be cut off only by independent connection of the power line and modification of layout of the chip side terminals, so that leak current in the defective block can be prevented completely. Besides, since a fuse element is not used in cutting of supply voltage, there is no problem of malfunction of the circuit blocks due to voltage drop.
Further, since selection of layout of a chip electrode is not needed, the chip manufacturing process can be simplified and unified.
B. Modified Examples
FIGS. 15 to 17 show modified examples of the chip of the second embodiment.
Similarly, as shown in
The same effects as in the second embodiment are obtained, when two or more of the processing elements PE0, PE1, PE2, PE3 are defective blocks NG and a power source terminal 14 is not disposed on the defective blocks NG.
C. Manufacturing Method
First, after forming circuit blocks such as a controller and processing elements on the chip, and also forming chip terminals (bumps), the operation of these circuit blocks is tested. This operation test is intended to check the functions of the circuit blocks by bringing a tester probe into contact with the chip terminals (step ST1).
Depending on results of the operation test, layout of chip side terminals (bumps) of the package is selected. For example, when the processing element PE0 is determined to be defective, a layout in which no chip side terminal is disposed on the portion corresponding to the processing element PE0 is selected (step ST2).
Finally, by packaging for mounting the chip on the selected package, the processing device of the second embodiment is obtained (step ST3).
D. Others
Also in the second embodiment, by cutting off supply voltage (VDD or VSS) to at least one of defective blocks, the purpose of preventing leak current is achieved. The second embodiment is also applicable in the case of using three or more supply voltages (VDD1, VDD2, . . . , VSS).
The second embodiment has an effect of preventing leak current in a defective block of a processing device having plural processing elements.
A third embodiment of the invention relates to a processing device in which presence or absence of cutting of a feeding route of supply voltage is set in each processing element in PCB side terminals (bumps) of package.
A. Configuration
FIGS. 19 to 21 show the processing device according to the third embodiment.
The structure of a chip 10 is same as in the second embodiment.
That is, as shown in
On one side of the package 11, PCB side terminals (bumps) 13 are disposed in an array. On the other side of the package 11, a recess for mounting the chip 10 is provided, and chip side terminals (pads) 14 are disposed in an array in the recess corresponding to the chip terminals 12.
In the third embodiment, the package 11 incorporates plural independent power source plates VDD for PE0, VDD for PE1, VDD for PE2, and VDD for PE3 corresponding to the plural processing elements PE0, PE1, PE2, and PE3.
In the power source plate VDD for PE0 corresponding to the processing element PE0 determined to be a defective block NG, the PCB side terminal (bump) 13 of the package 11 is not connected in order to cut off feed of supply voltage to the processing element PE0.
Therefore, supply voltage will never be fed to the processing element PE0.
The package explained herein is only an example, and the example of the invention is not limited to the type of the package, but can be applied in various forms of package.
According to this configuration, supply voltage to a defective block can be cut off only by independent connection of the power line and modification of layout of the PCB side terminals, so that leak current in the defective block can be prevented completely. Besides, since a fuse element is not used in cutting of supply voltage, there is no problem of malfunction of the circuit blocks due to voltage drop.
Further, since selection of layout of a chip electrode is not needed, the chip manufacturing process can be simplified and unified.
B. Manufacturing Method
First, after forming circuit blocks such as a controller and processing elements on the chip, and also forming chip terminals (bumps), the operation of these circuit blocks is tested. This operation test is intended to check the functions of the circuit blocks by bringing a tester probe into contact with the chip terminals (step ST1).
Depending on results of the operation test, layout of the PCB side terminals (bumps) of the package is selected. For example, when the processing element PE0 is determined to be defective, a layout in which no PCB side terminal is connected to the power source plate corresponding to the processing element PE0 is selected (step ST2).
Finally, by packaging for mounting the chip on the selected package, the processing device of the third embodiment is obtained (step ST3).
C. Others
In the third embodiment, in the same manner as in the first and second embodiments, it is applicable to a case in which one of the processing elements PE1, PE2, and PE3 is defective, or to a case in which two or more of the processing elements PE0, PE1, PE2, and PE3 are defective.
Also in the third embodiment, by cutting off supply voltage (VDD or VSS) to at least one of defective blocks, the purpose of preventing leak current is achieved. The third embodiment is also applicable in the case of using three or more supply voltages (VDD1, VDD2, . . . VSS).
The third embodiment has an effect of preventing leak current in a defective block of a processing device having plural processing elements.
3. The examples of the invention can be applied in processing devices such as a microprocessor, a graphic processor, a digital signal processor, and a microcomputer.
The processing device according to the examples of the invention can be used in various applications depending on the number of effective processing elements as shown in
4. The examples of the invention have effects of preventing leak current in a defective block of a processing device having plural processing elements.
With respect to the examples of the invention, plural processing elements may be those having the same function, and in addition thereto, may be duplicate blocks identical in layout.
Duplicate block may be one of a core processor of a multicore processor, and a shader processor of a graphic processor.
Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.
Number | Date | Country | Kind |
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2005-133631 | Apr 2005 | JP | national |