This application claims the benefit of priority to German Application No. 103 55 333.9, which was filed in the German language on Nov. 27, 2003, the contents of which are hereby incorporated by reference.
The invention relates to a device and a method for detecting the overheating of a semiconductor device.
Semiconductor devices, e.g. appropriate, integrated (analog or digital) computing circuits, semiconductor memory devices such as functional memory devices (PLAs, PALs, etc.) and table memory devices (e.g. ROMs or RAMs, in particular SRAMs and DRAMs, e.g. SDRAMs), etc. are subject to comprehensive tests in the course of their manufacturing process as well as subsequent to their manufacturing.
For instance, even before all the desired processing steps have been performed on the wafer (i.e. already in a semifinished state of the semiconductor devices), the (semifinished) devices (that are still being on the wafer) may, at one or a plurality of testing stations, be subject to appropriate testing methods (e.g. so-called kerf measurements at the wafer scrib frame) by means of one or a plurality of testing apparatuses.
After the finishing of the semiconductor devices (i.e. after performing all the wafer processing steps), the semiconductor devices may be subject to further testing methods at one or a plurality of (further) testing stations—for instance, the finished devices—that are still being on the wafer—may, by means of appropriate (further) testing apparatuses, be tested appropriately (“wafer tests”).
After the sawing (or scribing, and breaking, respectively) of the wafer, the devices that are then available as individual devices and are loaded into so-called carriers may be subject to appropriate further testing methods at one or a plurality of (further) testing stations.
Correspondingly, one or a plurality of further tests may (at corresponding further testing stations, and by using corresponding, further testing apparatuses) be performed e.g. after the installation of the semiconductor devices in the corresponding semiconductor device housings, and/or e.g. after the installation of the semiconductor device housing (along with the respectively incorporated semiconductor devices) in appropriate electronic modules (so-called module tests), etc.
Semiconductor devices, e.g. SDRAMs, react sensitively to strong heating.
By being heated beyond particular threshold temperatures, a semiconductor device may be damaged irreversibly or may be destroyed, respectively.
Such damages may e.g. occur in the course of the semiconductor device manufacturing process, but, for instance, also after the manufacturing only, e.g. during the soldering of the corresponding device, or during operation.
It is in particular partial damages that can not or only with relatively high effort be detected by means of the above-mentioned testing methods.
It is an object of the invention to provide a novel device and a novel method for detecting the overheating of a semiconductor device.
This and further objects are achieved by the subject matters of claims 1 and 20.
Advantageous further developments of the invention are indicated in the subclaims.
In accordance with a basic idea of the invention, a device for detecting the overheating of a semiconductor device is provided, said device comprising a temperature measuring means changing its electric conductivity when the temperature of the semiconductor device changes.
Advantageously, the temperature measuring means is designed such that the change in the electric conductivity of the temperature measuring means occurring when the temperature of the semiconductor device changes is irreversible.
Thus, it is relatively easy to determine whether there is the risk that a semiconductor device was—temporarily—overheated and might thus have been damaged irreversibly or destroyed, respectively.
In the following, the invention will be explained by means of several embodiments and the enclosed drawing. The drawing shows:
a a schematic representation of a device provided with a semiconductor device for detecting the overheating of the semiconductor device, in accordance with a first embodiment of the invention, in a state before the semiconductor device has been subject to relatively high temperatures;
b a schematic representation of the device illustrated in
c a top view of the device illustrated in
a a schematic representation of a device provided with a semiconductor device for detecting the overheating of the semiconductor device, in accordance with a second embodiment of the invention, in a state before the semiconductor device has been subject to relatively high temperatures;
b a schematic representation of the device illustrated in
c a top view of the device illustrated in
a a sectional view of a device provided with a semiconductor device for detecting the overheating of the semiconductor device, in accordance with a third embodiment of the invention, in a state before the semiconductor device has been subject to relatively high temperatures;
b a sectional view of the device illustrated in
c a top view of the device illustrated in
d a top view of the device illustrated in
a shows a schematic, lateral sectional view of a device 1 provided with a semiconductor device for detecting the overheating of the semiconductor device, in accordance with a first embodiment of the invention, in a state before the semiconductor device has been subject to relatively high temperatures.
The overheating detection device 1 may, for instance, be arranged directly at the surface of a corresponding semiconductor device, or e.g. in the interior of the semiconductor device.
The semiconductor device may, for instance, be an appropriate, integrated (analog or digital) computing circuit, or e.g. a semiconductor memory device such as a functional memory device (PLA, PAL, etc.), or a table memory device (e.g. a ROM or a RAM, in particular a SRAM or a DRAM, e.g. a SDRAM), and/or a combined computing circuit/memory device, etc.
In accordance with
As is illustrated in
Again referring to
A partial region 3′ of the measuring section 3—positioned substantially in the middle between the contact elements 2a, 2b—is (relatively strongly) doped, e.g. relatively strongly n-doped or relatively strongly p-doped, i.e. is of relatively good conductivity.
As compared to this, the two partial regions 3″ of the measuring section—positioned directly below the contact elements 2a, 2b, or adjacent to or contacting, respectively, the contact elements 2a, 2b—are undoped (or, alternatively: only weakly n- or p-doped), i.e. are of no or only poor conductivity.
With the doped partial region 3′, doping may be largest at or near an imagined plane A passing perpendicularly through the partial region 3′ (i.e. at a central region), and may continue decreasing with the increasing lateral distance from this imagined plane A.
The doped partial region 3′ may, for instance, be generated by a doping being injected locally into the—initially undoped—region 3 (e.g. by means of conventional diffusion methods, (ion) implantation methods, etc.).
As results from
Thus, the—conductive—partial region 3′ is in the initial state (due to the respective non-conductive partial region 3″ positioned, in accordance with
When the semiconductor device is heated, the outer limit or the respective lateral edge region, respectively, of the doped partial region 3′ is shifted—due to corresponding diffusion of the doping atoms contained in the partial region 3′—laterally in the direction of the contact elements 2a, 2b (as is illustrated in
As is illustrated in
Thus—after the overheating of the semiconductor device (exceeding of the threshold temperature T)—the contact element 2a, the partial region 3′, and the contact element 2b are—irreversibly—electrically connected with one another (2nd state).
The above-mentioned threshold temperature T is chosen such that from this temperature onwards there would be the risk of the semiconductor device being damaged irreversibly or destroyed, respectively.
The first and second contact elements 2a, 2b may, for instance, be connected directly by means of appropriate bonding wires, or e.g. indirectly by means of corresponding lines provides in or at the semiconductor device, to corresponding pins of the device housing accommodating the semiconductor device.
The first pin—that is connected with the first contact element 2a—may e.g. be connected to a first terminal of a test device, and the second pin—that is connected with the second contact element 2b—may e.g. be connected to a second test device terminal.
By applying an appropriate voltage between the first and the second test device terminals (and thus between the first and the second contact elements 2a, 2b), and subsequently measuring whether a corresponding current then flows between the contact elements 2a, 2b or not (or whether the intensity of the current flowing exceeds a predetermined threshold value), there may be determined whether no electrical connection exists between the contact elements 2a, 2b (initial state,
a shows a schematic, lateral sectional view of a device 11 provided with a semiconductor device for detecting the overheating of the semiconductor device, in accordance with a second embodiment of the invention, in a state before the semiconductor device has been subject to relatively high temperatures.
The overheating detection device 11 may, for instance, be arranged directly at the surface of a corresponding semiconductor device, or e.g. in the interior of the semiconductor device.
The semiconductor device may e.g. be an appropriate, integrated (analog or digital) computing circuit, or e.g. a semiconductor memory device such as a functional memory device (PLA, PAL, etc.), or a table memory device (e.g. a ROM or a RAM, in particular a SRAM or a DRAM, e.g. a SDRAM), and/or a combined computing circuit/memory device, etc.
The overheating detection device 11 comprises, in accordance with
The contact elements 12a, 12b may e.g. (correspondingly similar as with the embodiment illustrated in
As is illustrated in
During the manufacturing of the overheating detection device 11, the entire region of the measuring section 13 positioned below and between the contact elements 12a, 12b (e.g. the entire measuring section region) is first of all, e.g. by means of conventional diffusion methods, (ion) implantation methods, etc., relatively strongly doped, e.g. relatively strongly n-doped or relatively strongly p-doped, so that the entire measuring section region (or the entire measuring section 13, respectively) is then of—relatively good—conductivity.
Subsequently, a partial region 13′ of the measuring section—positioned substantially in the middle between the contact elements 12a, 12b—is, by means of appropriate, conventional method technologies, treated such that the above-mentioned semiconductor material changes from an initially non-amorphous, crystalline state to an amorphous state.
This may e.g. be effected by the partial region 13′ (e.g. —as illustrated in
The two partial regions 13′ of the measuring section 13—positioned directly below the contact elements 12a, 12 or adjacent to or contacting the contact elements 12a, 12, respectively—remain in the above-mentioned crystalline, i.e. conductive, state.
Since—as is illustrated in
Thus—with the initial state of the overheating detection device 11 illustrated in
If the semiconductor device is heated beyond a predetermined threshold temperature T (wherein the heating e.g. has to prevail for a certain, relatively short period t only, e.g. t<5 sec, or e.g. t<1 sec, or t<0.5 sec), the amorphous structures prevailing in the partial region 13′ again change to corresponding crystalline structures, this rendering the partial region 13′ electroconductive (again).
Thus—after the overheating of the semiconductor device (exceeding of the threshold temperature T)—the contact element 12a and the contact element 12b are—irreversibly—electrically connected with one another (2nd state).
By an appropriate choice of the (semiconductor) materials, the dimensions of the partial region 13′, the duration and/or the intensity of the laser treatment, etc., the above-mentioned threshold temperature T may be modified or adjusted, respectively (on the exceeding of which the partial region 13′ becomes electroconductive (again) (or—for the test method explained in detail further below—becomes correspondingly conductive to such an extent that the test provides a result “not passed”).
The threshold temperature T may advantageously be chosen such that, from this temperature onwards, there would be the risk of the semiconductor device being irreversibly damaged or destroyed, respectively.
The first and second contact elements 12a, 12b may e.g. be connected directly by means of appropriate bonding wires, or e.g. indirectly by means of appropriate lines provided in or at the semiconductor device, to corresponding pins of the device housing accommodating the semiconductor device.
The first pin—that is connected with the first contact element 12a—may e.g. be connected to a first terminal of a test device, and the second pin—that is connected with the second contact element 12b—may e.g. be connected to a second test device terminal.
By applying an appropriate voltage between the first and the second test device terminals (and thus between the first and the second contact elements 12a, 12b), and subsequently measuring whether a corresponding current then flows between the contact elements 12a, 12b or not (or whether the intensity of the current flowing exceeds a predetermined threshold value), there may be determined whether no electrical connection exists between the contact elements 12a, 12b (initial state,
a shows a schematic, lateral sectional view of a device 21 provided with a semiconductor device for detecting the overheating of the semiconductor device, in accordance with a third embodiment of the invention, in a state before the semiconductor device has been subject to relatively high temperatures.
The overheating detection device 21—in particular two contact elements 22a, 22b provided with this device, and a metal layer, in particular a softmetal layer 24 (of relatively good conductivity) positioned therebetween—may e.g. be arranged directly at the surface of the corresponding semiconductor device, or e.g. on a special substrate, or e.g. in the interior of the semiconductor device. The overheating detection device 21 is surrounded by non-conductive material, e.g.—undoped—silicon (e.g. a correspondingly similar or identical—undoped—basic material as with the remaining portion of the semiconductor device).
The semiconductor device may, for instance, be an appropriate, integrated (analog or digital) computing circuit, or e.g. a semiconductor memory device such as a functional memory device (PLA, PAL, etc.), or a table memory device (e.g. a ROM or a RAM, in particular a SRAM or a DRAM, e.g. a SDRAM), and/or a combined computing circuit/memory device, etc.
In the overheating detection device 21—as is, for instance, illustrated in
As is illustrated in
Again referring to
As is illustrated in
In a region positioned roughly in the middle between the contact elements 22a, 22b, the metal layer 24 is—relatively strongly—tapered, so that there the metal layer 24 has only a—relatively small—breadth b2 that may only amount to less than the half, e.g. less than a third, or less than a fourth, of the breadth b1 of the metal layer 24 at or close to the contact elements 22a, 22b.
As results from
As is illustrated in
The above-mentioned threshold temperature T is chosen such that, from this temperature onwards, there would be the risk of the semiconductor device being damaged irreversibly or destroyed, respectively.
For adjusting the threshold temperature T, the material, in particular metal/alloy used for constructing the metal layer 24, in particular may be chosen such that the melting point of the material is approximately identical to the above-mentioned threshold temperature T.
After the melting apart of the metal layer 24—at the above-mentioned tapered region having merely the breadth b2—two separate metal layer parts 24a, 24b—that are separated from each other electrically (by the air therebetween)—have, in accordance with
Thus—after the overheating of the semiconductor device (exceeding of the threshold temperature T)—the contact element 22a and the contact element 22b are—irreversibly—separated from one another electrically (2nd state).
By the above-described design of the metal layer 24 it is prevented that—after the metal layer 24 has been melted apart—the two single metal layer parts 24a, 24b that have been generated may combine with one another again (later).
This becomes possible in particular by the metal structure—here chosen by way of example and explained in detail above—with which the metal or alloy material, respectively, of the metal layer 24 is, in the melted-apart state, contracted—due to correspondingly acting capillary forces—to form the above-mentioned metal layer parts 24a, 24b at the two contact elements 22a, 22b.
This effect can also be supported, for instance, by an appropriate choice of the material and/or the property of the substrate positioned directly below the metal layer 24 (and possibly being selected specifically), in particular by taking into account the wetting characteristics of the material used for the metal layer 24 on the substrate.
The first and second contact elements 22a, 22b may, for instance, be connected directly by means of appropriate bonding wires, or e.g. indirectly by means of appropriate lines provided in or at the semiconductor device, to corresponding pins of the device housing accommodating the semiconductor device.
The first pin—connected with the first contact element 22a—may e.g. be connected to a first terminal of a test device, and the second pin—connected with the second contact element 22b—may e.g. be connected to a second test device terminal.
By applying an appropriate voltage between the first and the second test device terminals (and thus between the first and the second contact elements 22a, 22b), and subsequently measuring whether a corresponding current then flows between the contact elements 22a, 22b or not, there may be determined whether an electrical connection exists—via the metal layer 24—between the contact elements 22a, 22b (initial state,
Instead of every single one of the above-described overheating detection devices 1, 11, 21, a plurality of—e.g. two, three, or more—overheating detection devices 1, 11, 21 (e.g. each constructed correspondingly similar as described above) may also be arranged on the same semiconductor device (each e.g. becoming electroconductive or non-conductive with the same or substantially the same threshold temperature T, or e.g. each with—possibly relatively strongly—different threshold temperatures T1, T2, T3, T4, etc. (so that—depending on the number of the different threshold temperatures T1, T2, T3, T4 used—the temperature range (T1-T2, T2-T3, etc.) including that temperature to which the semiconductor device was maximally subjected may be determined for the semiconductor device)).
List of Reference Signs
Number | Date | Country | Kind |
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103 55 333.9 | Nov 2003 | DE | national |