Microchip having a plurality of reconfigurable test structures

Abstract

The invention relates to a microchip with a multiplicity of reconfigurable test structures, wherein the microchip has a test input (TDI) and a test output (TDO), wherein the multiplicity of test structures can be connected to the test input (TDI) and the test output (TDO), wherein one intermediate memory is provided for each of the multiplicity of test structures, wherein each of the multiplicity of test structures can be tested separately and concurrently with the aid of the respective intermediate memory and a corresponding individual control.

Claims

1. A microchip comprising a multiplicity of reconfigurable test structures, wherein: the microchip has a test input (TDI) and a test output (TDO); each reconfigurable test structure of the multiplicity of reconfigurable test structures is connected to the test input (TDI) and to the test output (TDO); the microchip comprises a plurality of intermediate blocks including a respective intermediate block provided for each of the reconfigurable test structures; each of the intermediate blocks comprises at least a memory and a control; each of the memories of the intermediate blocks is configured to store a respective test stimulus for the respective reconfigurable test structure; each of the controls of the intermediate blocks is configured to execute the respective test stimulus for the respective reconfigurable test structure; and each of the multiplicity of reconfigurable test structures is configured to be tested separately and concurrently with the aid of the respective intermediate block.

2. The microchip according to claim 1, wherein each of the respective intermediate blocks is configured to decompress the respective test stimulus prior to execution.

3. The microchip according to claim 1, wherein each of the respective intermediate blocks is configured to compress a result of the respective test stimulus prior to forwarding to the test output (TDO).

4. The microchip according to claim 1, wherein each of the reconfigurable test structures provides an in-field test.

5. The microchip according to claim 1, wherein at least a portion of the multiplicity of reconfigurable test structures is configured to be tested simultaneously.

6. The microchip according to claim 1, further comprising a plurality of instruments, wherein a respective instrument of the plurality of instruments is upstream of each of the respective intermediate blocks, wherein the plurality of instruments is configured to accept the respective test stimulus upon detection and provide the respective test stimulus to the respective intermediate block.

7. The microchip according to claim 1, wherein each of the respective intermediate blocks is configured to store a result of the respective test stimulus in the respective memory prior to forwarding to the test output (TDO).

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The invention is described in more detail in the following, with reference to the figures. In the figures:

(2) FIG. 1 shows a sectional overview of test structures according to the prior art,

(3) FIG. 2 shows a sectional overview of test structures according to the prior art,

(4) FIGS. 3a and 3b show schematic overviews of the signal path in a test structure according to the prior art in two successive configuration steps,

(5) FIG. 4 shows a further schematic overview of test structures according to the prior art,

(6) FIG. 5 shows a sectional overview of test structures according to embodiments of the invention,

(7) FIGS. 6 and 7 show an aspect according to embodiments of the invention,

(8) FIG. 8 shows a further aspect according to embodiments of the invention,

(9) FIG. 9 shows another further aspect according to embodiments of the invention,

(10) FIG. 10 shows schematic overviews according to embodiments of the invention, and

(11) FIG. 11 shows schematic overviews according to embodiments of the invention.

DETAILED DESCRIPTION

(12) The invention is described in more detail in the following, with reference to the figure. Here, it is to be noted that different aspects are described, which can be used individually or in combination in each case. That is to say, any aspect can be used with different embodiments of the invention, insofar as it is not explicitly represented as a pure alternative.

(13) Furthermore, in the following, for the sake of simplicity, reference is generally always only made to one entity. Insofar as not explicitly noted, the invention can however also have a plurality of the relevant entities in each case. In this respect, the use of the words “a”, “an” and “one” is only to be understood as an indication that at least one entity is used in a single embodiment.

(14) Embodiments of the invention are illustrated in FIGS. 5-11. In this case, a microchip according to the invention has a multiplicity of reconfigurable test structures DUT1, . . . DUT4. The number of reconfigurable test structures is not limited and only exemplary with 4 test structures in individual figures.

(15) The totality of the test structures are addressed via a common test input TDI and read out from a common test output TDO. That is to say, the microchip has a test input TDI and a test output TDO, wherein the multiplicity of test structures can be connected to the test input TDI and the test output TDO.

(16) An intermediate memory CSU0 . . . CSU3 is provided for each of the multiplicity of test structures. The size of the intermediate memory may be configured differently, depending on the test structure DUT1 . . . DUT4.

(17) Each of the number of test structures DUT1 . . . DUT4 can then be tested separately as well as concurrently, with the aid of the respective intermediate memory CSU0 . . . CSU3.

(18) In this case, concurrently means that different, particularly exclusory, regions of the test infrastructure (e.g. C.sub.1 and C.sub.2 in FIG. 6) can be used independently of one another.

(19) For example, DUT3 should be tested in FIG. 5. DUT3 corresponds to C3 in the following figures. Then, DUT3, just like the other test structures DUT1, DUT2, is connected to a common test bus (from TDI to TDO). However, this connection is produced by means of an instrument—abbreviated INST. A CJTAG unit, which controls the actual test inside a structure DUT1 . . . DUT3 to be tested, is located downstream of the instrument.

(20) That is to say, the tests or the control of the test infrastructure can proceed independently, so that execution of a test in the structure DUT1 does not impair the configuration of a different test in a different test structure DUT2, DUT3, or whilst a test is executing, test results of one or more different structures can be read out. That is to say, in the invention, a logic shift to the structural level takes place, so that test/control data for a plurality of test sequences in the substructure can be loaded in a block.

(21) However, the tests can also be instrumented in parallel. That is to say tests can be loaded in parallel by means of a suitable activation of the instruments.

(22) An exemplary infrastructure is outlined in FIG. 11. Here, test stimuli and/or test results are stored in an intermediate memory CSU0 . . . CSU3. Furthermore, a process counter PC may also additionally be provided for executing the test. In principle, the CIJTAG block (cf. FIG. 5) has the tasks of temporarily storing test data and test results, controlling test execution, (optional) test-data decompression and (optional) test-result compression within the respective test structure. Of course, the CIJTAG block can also take on further functions.

(23) That is to say, if the structure C3 is to be tested in FIG. 6, then it is provided with test and control data. To this end, the instrument in FIG. 7 accepts the test data upon detecting the selection and provides the test data to the CIJTAG block. Received test data in turn contain control data for a test. If such control data are contained, then the CIJTATG block activates the test structure accordingly. Test stimulus or test stimuli, which are contained in the test data, are then executed by the CIJTAG block under control. Test results are collected by the CIJTAG block and, upon renewed activation, provided to the instrument and read out via the output TDO.

(24) CIJTAG control data and test stimuli (what are known as test vectors) are contained in FIG. 8 by way of example. The CIJTAG control data may contain e.g. data relating to the number of test sequences and/or the length of the test sequences.

(25) Without limiting generality, it may also be provided, as shown in FIG. 9, that a multi-bit bus is used, i.e. different tests (in the example one test with test vectors 1 . . . n and a different test with test vectors n+1 . . . m) are carried out.

(26) Without limiting generality, it may be provided, as shown in FIG. 10, that test data are initially read into an intermediate memory/test-data buffer and are decompressed prior to execution. In this case, even only parts of the data can be compressed. For example, the control data may be uncompressed, whilst the test stimuli are compressed or vice versa.

(27) In the same way, it may also be provided, however, that the test results are compressed before they are read out from the test-data buffer via the instrument and read out via the TDO.

(28) Compression allows a reduction of the test-data quantity and thus time advantages during the transport of the data, so that can be configured in an accelerated manner and/or can be read out in an accelerated manner. The reduction is significant here in particular in that reading in and out of data takes place in many cases by means of an only 1-bit wide input TDI/output TDO. That is to say, whilst a test structure (de)compresses data, other test structures can be loaded/unloaded.

(29) It is noted in this case, that the compression/decompression can also optionally be designed to be configurable. For example, whether and, if appropriate, which data are to be (de)compressed can be signalled by means of the control data.

(30) Furthermore, it may be provided, that the test structure provides an in-field test.

(31) In addition, it may readily be provided in embodiments of the invention, that at least a portion of the multiplicity of test structures can be tested simultaneously.

(32) The invention makes it possible that concurrent and reconfigurable test infrastructures are possible for the in-production test. Compared to previous structures, the inventive test structures offer the possibility of testing components with a significantly lower time outlay/data outlay. As a result, in addition to the time saving achieved, the test quality can furthermore also be improved, as omitted tests can now take place within the previously required time.

(33) This advantage is also of utmost importance in the case of structures on microchips, which are becoming more complex and, at the same time, smaller.

(34) For in-field tests in particular, the invention allows the option of fulfilling the requirements of modern standards, such as e.g. ISO26262, which e.g. requires a self test in the range of milliseconds. Here, due to the concurrency, it is possible to control or carry out numerous test operations independently and simultaneously.